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Surface Coating Strategy: From Improving the Luminescence Stability to Lighting and Display Applications of All-Inorganic Cesium Lead Halide Perovskite Nanocrystals

Zehao Hu , Ting Chen , Yanqiao Xu , Weihui Jiang , Zhixiang Xie

Progress in Chemistry ›› 2021, Vol. 33 ›› Issue (9) : 1614 -1626.

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Progress in Chemistry ›› 2021, Vol. 33 ›› Issue (9) : 1614-1626 DOI: 10.7536/PC200821
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Surface Coating Strategy: From Improving the Luminescence Stability to Lighting and Display Applications of All-Inorganic Cesium Lead Halide Perovskite Nanocrystals
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Abstract

All-inorganic lead halide perovskite nanocrystals have extremely broad application prospects in light emitting diode, solar cell and biomarker fields due to their excellent optoelectronic properties, i.e. high fluorescence quantum yield, high color purity and wide color gamut. However, the unsatisfactory stability caused by the ionic characteristics has seriously hindered their further application. Although many strategies, i.e. metal ions doping, surface passivation and coating, have been developed to improve stability, how to maintain stability when exposed to air, water, and polar solvents is still an urgent issue. In addition, anion exchange in perovskite may limit its application in multicolor luminescence display field. It is an ideal and effective strategy to improve the stability of perovskite nanocrystals by surface coating to maintain the high fluorescence quantum efficiency and avoid anion exchange, which has been receiving considerable attention of researchers. In this review, we summarize the root of instability for lead halide perovskite nanocrystals, and introduce the current research progress of surface coating strategy for all-inorganic lead halide perovskite in detail, as well as its applications in the lighting and display field. Finally, the challenges concerning the development of the lead halide perovskite nanocrystals are outlined and the main future research directions are concluded.

Contents

1 Introduction

2 Properties of all-inorganic cesium lead halide perovskite nanocrystals

2.1 Crystal structure

2.2 Optical property

2.3 Stability

3 Surface coating strategy

3.1 Organic matrix coating

3.2 Inorganic oxide coating

3.3 Inorganic non-oxide coating

4 Applications of all-inorganic cesium lead halide perovskite in WLED

5 Conclusion and outlook

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Keywords

all-inorganic lead halide perovskite / nanocrystals / coating / optical property / lighting and display

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Zehao Hu, Ting Chen, Yanqiao Xu, Weihui Jiang, Zhixiang Xie. Surface Coating Strategy: From Improving the Luminescence Stability to Lighting and Display Applications of All-Inorganic Cesium Lead Halide Perovskite Nanocrystals. Progress in Chemistry, 2021, 33(9): 1614-1626 DOI:10.7536/PC200821

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1 Introduction

Metal halide perovskite materials were reported as early as 1983. According to their optical and electronic properties, researchers have prepared them into light-emitting devices and transistors[1]. Until 2012, metal halide perovskite materials as materials for dye-sensitized solar cells have attracted great interest because they can increase the absorption cross-section of devices and have excellent charge transport characteristics[2,3].
Lead halide perovskite materials can not only separate charge in photovoltaic devices, but also make charge recombination produce fluorescence phenomenon[2,3]. The relatively low non-radiative transition ratio and high color purity make it have good application prospects in the fields of light emitting diodes (LEDs) and lasers[4]. In 2014, researchers first synthesized lead halide perovskite nanocrystals, which have special physical and chemical properties due to quantum confinement effect and quantum size effect when their particle size is smaller than or close to the exciton Bohr radius of bulk materials.Uch as high photoluminescence quantum yield (PLQY), long carrier diffusion length, narrow full width at half maximum (FWHM), high optical absorption coefficient and defect tolerance, tunable emission wavelength over the entire visible range,Therefore, it has attracted wide attention of researchers in many fields, such as light-emitting diodes, backlight displays, fluorescence imaging, lasers, photovoltaics, photodetectors and catalysis[5][5][6][7][8][9][10][11][12]. Although lead halide perovskites have excellent optical properties, their ionic properties lead to poor stability, which has become a major obstacle to their practical application. The main performance is that the lead halide perovskite is very sensitive to the external environmental conditions (oxygen, humidity, heat and light, etc.), which easily leads to the destruction of the nanocrystalline surface, phase transition and agglomeration of nanoparticles. This is especially true in water and polar solvents, where the nanocrystals are typically quenched within seconds of exposure, resulting in the destruction of structural integrity and rapid decay of optical properties. In addition, rapid ion exchange between lead halide perovskites with different chemical compositions hinders their application in the field of multicolor luminescent displays. The thermal decomposition temperatures of organic/inorganic hybrid perovskite MAPbI3 and FAPbI3 are 150 ~ 200 ℃ and 290 ~ 300 ℃, respectively. In contrast, the thermal stability of all-inorganic cesium-lead halide perovskite CsPbX3 is more excellent, and the thermal decomposition temperature reaches 400 ~ 500 ℃, so it has attracted wide attention of researchers[13]. The instability greatly limits the synthesis, storage and application of lead halide perovskite. Therefore, it is an important issue to explore the highly stable all-inorganic cesium lead halide perovskite materials. To solve this problem, researchers have proposed many solutions, including ion doping, surface modification and surface coating. Among them, ion doping can not only effectively regulate the photoelectric properties of nanocrystals, but also improve their stability, but it has also been proved to greatly affect the characteristics of band-edge carriers and enhance the formation energy[14]. Surface modification reduces surface defects and enhances optical properties through the interaction of strong ligands with surface atoms of nanocrystals, but it is still a challenge to prevent surface damage and crystalline phase transition in polar solvents, especially water[15,16]. Surface coating can isolate the environment and greatly reduce the degradation of nanocrystals, thus effectively improving the water resistance and oxygen resistance of nanocrystals, while avoiding the reduction of efficiency caused by agglomeration, so it has gradually become a research hotspot in recent years[17]. At present, most of the review articles on perovskite nanocrystals focus on their preparation methods, optical properties and applications, but there are few reports on the coating approach and the related optical properties control mechanism[18]. In this paper, the structure and related luminescence mechanism of perovskite nanocrystals are systematically reviewed, and the degradation mechanism and instability reasons of nanocrystals under different conditions are pointed out.The related work of improving the stability of perovskite nanocrystals by surface coating is introduced in detail.Finally, the application of perovskite nanocrystals in the field of lighting and display is introduced, and its future development is prospected.

2 Properties of All-Inorganic Caesium-Lead Halide Perovskite Nanocrystals

2.1 Crystal structure

The perovskite material has a ABX3structure as shown in fig. 1. A is an organic or inorganic cation (MA+, Cs+, FA+),B is a metal cation (such as Pb2+,The Mn2+ and the Sn2+),X are halogen anions (such as Cl-, Br- and I-)[19]. Ideally, the perovskite crystal belongs to the cubic system, but because of the Jahn-Teller effect, the center shift effect of the octahedral metal B ion and the small radius of the a ion occupying the octahedral gap,The orthorhombic and orthorhombic crystal structures are formed due to the decrease of lattice symmetry caused by the easy twist of the lead halide octahedron, and the three crystal structures can be transformed into each other at different temperatures[20][21]. Evarestov et al. Calculated the formation energy of all inorganic cesium lead halide perovskite nanocrystals CsPbX3 by density functional theory, and compared the stability of different perovskites from the perspective of energy change, which was CsPbBr3>CsPbI3>CsPbCl3 in turn[22]. It is noteworthy that the CsPbBr3 film transforms from orthorhombic phase to tetragonal phase at 88 ℃ and finally to cubic phase at 130 ℃, and the whole phase transformation process does not cause significant color change[23][24]. While CsPbI3 in aqueous solution will change from orthorhombic phase to cubic phase and cause significant color change when heated to 305-308 ° C[25].

2.2 Photoelectric characteristic

Cubic metal halide perovskites are direct band gap semiconductors[26]. Compared with bulk semiconductor materials, the size of lead halide perovskite nanocrystals is close to the exciton Bohr radius, the carriers are limited in three dimensions, and the energy level structure evolves from a continuous energy band structure to a discontinuous energy level structure. Normally, the electrons in the nanocrystal tend to be arranged at the valence band position with lower energy, and when an electric field or excitation light is applied, the electrons are excited by a pulse to absorb the energy of photons and jump to the conduction band with higher energy,When the pulse is over, the electrons will return to the valence band from the conduction band and emit light with a specific frequency. The emission wavelength is determined by the band gap of the nanocrystal, so the emission wavelength can be adjusted by adjusting the band gap of the nanocrystal to cover the entire visible light band. The impurities and lattice defects of traditional semiconductor materials (such as Si, CdTe and GaAs) can act as doping centers or electron traps, so it is necessary to avoid the generation of defect levels in the process of preparation and application. In contrast, perovskite nanocrystals have higher defect tolerance and higher fluorescence quantum yield even without surface passivation[27]. This is because: (1) There may be three kinds of point defects in nanocrystals, namely, vacancy, interstitial and antisite (Fig. 2 (a)), among which the formation energy of vacancy defect is the lowest, so vacancy is the main defect in its crystal lattice, while interstitial defects and antisite defects in deep trap state are more difficult to form[28⇓⇓~31]. (2) The band gap of conventional semiconductors is formed between the bonding (σ) and antibonding (σ*) orbitals, while the band gap of lead halide perovskite nanocrystals is formed between the two antibonding orbitals. Thus, the defect state will only form shallow traps or will be enclosed in the conduction or valence band and will not strongly affect radiative recombination and other optical properties. (3) The soft and dynamic properties of the perovskite lattice make it both crystalline and liquid-like, protecting its carriers from being trapped and scattered[33,34].
Nanocrystals have huge specific surface area and surface energy due to their extremely small grain size, which results in many uncoordinated atoms (dangling bonds) and defects (including vacancies, dislocations and antisites of surface elements of quantum dots) on their surfaces[13]. After the formation of surface defects, the nanocrystals will produce localized States and defect States, which will increase the probability of non-radiative recombination and reduce the quantum yield of the nanocrystals. In addition, the surface of nanocrystals is prone to oxidation under relatively harsh conditions such as light, heat, water and electromagnetic, which increases the surface defects of nanocrystals and reduces their fluorescence lifetime[35].
The ligand modified on the surface of the nanocrystal can not only limit the growth of particles during the formation of the nanocrystal, but also passivate surface defects and improve the oxidation resistance and chemical stability of quantum dots.Therefore, the high PLQY of lead halide perovskite nanocrystals depends largely on the organic ligands on the surface of the nanocrystals, such as oleic acid (OA), oleylamine (OLA) and trioctylphosphine (TOP). However, long-chain organic ligands (such as OLA) have poor conductivity, which hinders charge injection and transport. Dai et al. Proposed the use of short-chain ligand 1,4-n-butylamine dibromide (BOABr2) as a passivation material. The BOABr2 has a short carbon chain and contains two amino groups at the end of the chain, which can shorten the charge transport pathway and facilitate charge transfer between crystals. Therefore, the charge transport of the prepared CsPbBr3 nanocrystalline film is significantly enhanced[36].

2.3 Stability

Lead halide perovskite nanocrystals are completely ionic crystals, which are unstable in many common solvents, especially in polar solvents, and their optical properties are easily damaged, even the crystal structure will change[37]. de Roo et al. First characterized the surface state of CsPbBr3 by 1H nuclear magnetic resonance spectroscopy (1HNMR)[38]. Due to the surface instability of perovskite nanocrystals, their ligands (such as oleic acid, oleylamine, etc.) Are easily damaged, and the nanocrystals dissolve and recrystallize after contacting with polar solvents, resulting in large particles and a significant decrease in PLQY[39]. At the same time, the amount of polar solvent added has a significant effect on the optical properties of the lead halide perovskite nanocrystals.It was found that the colloidal stability of the nanocrystals was destroyed when the polar solvent was added to remove the residual precursors by centrifugation.With the increase of the amount of polar solvent added, the optical properties of the samples gradually decreased or even disappeared[39].
In addition, perovskite materials exhibit sensitivity to moisture, light, and temperature due to their low formation energies[40]. Perovskite nanocrystals will degrade rapidly when exposed to air, and remain sensitive to residual water and oxygen even after encapsulation with a resin sealant[41]. Diroll et al. studied the relationship between temperature and the stability of lead halide perovskite. Although the lead halide perovskite CsPbX3 nanocrystals formed by different halogens have different resilience to temperature, they all show irreversible degradation at higher temperatures (e.g., over 450 K)[42]. In addition to polar solvents, air and high temperature, harsh environments such as magnetic field and electron flow can affect the stability of lead halide perovskite nanocrystals.

3 Surface coating strategy

At present, the main ways to improve the stability of perovskite nanocrystals are ion doping, organic ligand modification and surface coating[43⇓~45]. Doping, based on crystal modification and Goldsmith's tolerance factor theory, enhances the stability of nanocrystals to some extent. For example, Huang et al. Substituted K+ with the same valence and similar ionic radius as Cs+, and the prepared K-CsPbBr3 nanocrystals can still maintain 97.9% of the initial strength after 30 hours of storage[46]. Li et al. Proposed a simple and effective supersaturated solution method to dope Na+ into the lattice of CsPbBr3 to improve its stability[47]. The luminescent intensity of the WLED device prepared by the quantum dots is only reduced by 15% after continuously working for 500 hours. Although the doping method can improve the stability of perovskite materials from the structure, the melting point of the doped samples is lower, and the original crystal structure does not change[48]. Organic ligand-modified surfaces usually use coordination compounds to enhance ligand binding or special methods to cross-link organic solvent molecules. For example, Krieg et al. Used long-chain organic molecule N, N-dimethyl-N- (3-sulfopropyl) -1-octadecylammonium inner salt to coordinate the surface of CsPbX3, thus improving the stability of nanocrystals, and the quantum yield remained above 90% after four times of purification[15]. Wu et al. Used trioctylphosphine oxide (TOPO) to modify the surface of CsPbX3 nanocrystals[49]. Due to the strong polarity of TOPO, the capping ability of TOPO is stronger than that of the conventional ligand oleylamine and oleic acid (OA/OAm), so it shows better stability in polar solvents. After ethanol treatment for 2 H, the emission intensity of the nanocrystals synthesized with TOPO and OA/OAm decreases by 5% and 86%, respectively.Pan et al. Used TDPA and TBAI as surface ligands to synthesize nanocrystals with good stability. TDPA can form stable hydrogen bonds with halogen ions to prevent the decomposition of CsPbI3, while TBAI passivates the halogen vacancies on the surface of nanocrystals. The synergistic effect of the two makes nanocrystals show good stability, and they still maintain 90% of the initial emission intensity after 20 days of storage[50]. However, the modified perovskite nanocrystals will still undergo dynamic ligand exchange with the solution, and will still degrade in harsh environments such as high humidity, polar solvents or high temperature. Ionic liquids were introduced into the preparation of perovskite nanocrystals for the first time in our group, which passivated the surface defects, greatly improved the fluorescence properties, and significantly improved the storage and ultraviolet light stability of nanocrystals[51]. Compared with the above two methods to improve the stability of nanocrystals, surface coating is one of the most simple and effective ways, which can directly isolate perovskite materials from the environment by coating organic/inorganic shells without destroying the structural properties of nanocrystals, thus effectively improving the stability of nanocrystal. Coating perovskite nanocrystals usually adds organic or inorganic matrix to the perovskite precursor solution to form a dense network to isolate the nanocrystals from the external environment such as water and oxygen, thus improving the stability of the nanocrystals. At the same time, the surface coating can also isolate the contact between the nanocrystals and prevent the fluorescence quenching caused by the agglomeration of the nanocrystals. Henglein found that the coated nanocrystals had better stability, surface properties and optoelectronic properties than their single crystals[52]. Zhou et al. Synthesized core-shell semiconductor nanocrystals, which greatly improved the photoelectric properties of semiconductor nanocrystals and suppressed the scintillation phenomenon, making them more widely used in areas requiring sustained excitation and emission properties, such as point light sources and single molecule tracking[53][54][55]. Jiang et al. Synthesized CsPbX3@SBS, CsPbX3@PMMA, CsPbX3@PS films and fibers by embedding nanocrystals into poly (styrene-butadiene-styrene) (SBS), poly (methyl methacrylate) (PMMA) and polystyrene (PS), respectively, and the quantum yield and stability were improved to varying degrees[56]. Zhong et al. Solved the problem of single particle coating of CsPbX3 nanocrystals by a simple one-pot method, and the CsPbX3@SiO2 core-shell nanocrystals prepared showed excellent long-term stability in humid air and under the condition of ultrasonic treatment in water[57]. Shi et al. Synthesized two kinds of core-shell structure nanocrystals, CsPbBr3@Cs4PbBr6 and CsPbBr3@CdS, respectively, and made great breakthroughs in stability and photoelectric properties[45]. Compared with polymer matrix, the encapsulation of inorganic matrix has better intrinsic characteristics (such as thermal stability and light stability), so it has received more and more attention in the field of lead halide perovskite nanocrystals. In the following, three aspects of organic, inorganic oxide and inorganic non-oxide matrix coating will be introduced in detail from different matrix materials.

3.1 Organic matrix coating

Organic matrix encapsulation usually uses long-chain polymer molecules (such as organosilane, etc.) To form a compact network to encapsulate the lead halide perovskite to avoid contact with the outside world, so it can usually improve the environmental stability of the lead halide perovskite nanocrystals, passivate the surface state of the nanocrystals and improve the fluorescence properties. Although the polymer matrix shows excellent water resistance, its large oxygen diffusion coefficient, poor thermal stability and hydrophobicity hinder further improvement of its stability. Protesescu et al. Embedded CsPbBr3 nanocrystals into PMMA through photopolymerization to prepare composites with excellent optical transparency and bright luminescence[58]. However, compared with most inorganic matrix materials, PMMA has a higher oxygen diffusion coefficient (3.3×10-9cm2·s-1 at 22 ℃), which can not avoid the influence of photooxidation on nanocrystals, so the stability of nanocrystals under harsh conditions (such as ultraviolet radiation) still needs to be improved[59][60]. Zhang et al. synthesized polyvinylpyrrolidone (PVP) -coated CsPbBr3 nanocrystals by solution self-assembly at room temperature, as shown in Figure 3 (a)[61]. PVP was physically adsorbed on the surface of the CsPbBr3 nanocrystals as an encapsulation ligand to form a protective layer, and also acted as an interface layer to embed the nanocrystals into the polystyrene microspheres. Huang et al. Proposed a method of surface protection of CsPbX3 by polyhedral polysilsesquioxane (POSS), and synthesized lead halide perovskite nanocrystals with good water stability. CsPbBr3@POSS nanocrystals can still emit strong green light after dispersing in water for 10 weeks, and can also prevent anion exchange phenomenon[62].
Coating the surface of nanocrystals with super-hydrophobic organic polymers can reduce the erosion of water on nanocrystals and improve their stability. Xuan et al. Proposed a new method to coat a layer of super-hydrophobic porous organic polymer frameworks (SHFW) on the surface of hydrophobic porous organic polymer frameworks.Due to the special porous structure of SHFW, its contact angle with water is greater than the 150o, so it shows excellent hydrophobic properties as a coating layer. The prepared CsPbBr3@SHFW nanocrystals still have 91% of the initial yield of PLQY after being stored in water for 31 days, and can still emit bright green fluorescence after being stored for 6 months, as shown in Figure 4[63]. Polystyrene (PS) is also an organic polymer with excellent hydrophobic properties, which helps to protect perovskite from moisture erosion. At the same time, polystyrene has a swelling-shrinking phenomenon in different organic solvents, which is easy to wrap perovskite materials. Wei et al. prepared CsPbBr3@PS composite beads by using the swelling-shrinking phenomenon in toluene and n-hexane, and the synthesis process is shown in Figure 3 (B)[64]. The composite bead has excellent water resistance, acid resistance and alkali resistance, still keeps the luminous effect after being immersed in water for 9 months, is not affected in acid/alkali aqueous solution, phosphate buffer solution and culture medium biological buffer solution, and shows excellent stability in the fields of light-emitting diodes and cell labeling.
Metal-organic frameworks (MOFs) coating is also an effective method to protect all-inorganic Cesium lead halide perovskite nanocrystals. Metal organic framework (MOF) is a kind of porous hybrid material, which is composed of inorganic metal centers and organic connecting matrix through coordination bonds. It has the characteristics of diverse structures, large specific surface area and adjustable pore size, and its porosity can be greater than 50% of the crystal volume of MOF[66][67]. Ren et al. prepared CsPbX3@ZJU-28 nanocrystals by embedding all-inorganic cesium-lead-halide perovskite nanocrystals into MOF (ZJU-28), as shown in Figure 5[65]. The CsPbBr3 powder almost has no luminescence effect at 80 ℃, while the CsPbX3@ZJU-28 powder can still maintain 64. 7% of its original PL intensity, and still has good fluorescence effect at 160 ℃, indicating that the thermal stability of the sample has been improved. After 80 H of UV irradiation, 84.5% of the original luminescence intensity was retained, and after 60 d of exposure to air (20 ℃, 15%), 83.5% of the original luminescence intensity was retained, and the anion exchange reaction was significantly inhibited. Li et al. Used MOF to prepare CsPbX3@Cu-BDC,MOF with bright fluorescence effect. The highly uniform microporous structure can effectively prevent the aggregation of nanocrystals in the synthesis process, so the nanocrystals have good dispersion and stability in the air environment, and the luminescence performance does not decay significantly after 60 days[68].
The organic polymer coating has the advantages of high flexibility, low density and strong processability, and the compact polymer chain can passivate the surface defects of the nanocrystal and isolate the external environment, so that the water stability and thermal stability of the all-inorganic cesium lead halide perovskite nanocrystal are remarkably improved.

3.2 Inorganic oxide matrix coating

Polymer coating can significantly improve the water stability of lead halide perovskite nanocrystals, but the polymer itself is not stable enough in high temperature environment, and the heating process may lead to the shedding of ligands from the surface of nanocrystals and the quenching of fluorescence[69]. In contrast, inorganic coating has obvious advantages in improving the mechanical and thermal properties of lead halide perovskite. The effective coating can protect the bonding ligands on the surface of the nanocrystals, avoid the formation of emission or non-emission traps, and prevent the photoinduced regrowth and fluorescence decay[48]. SiO2 is a commonly used inorganic oxide coating material, which has the characteristics of chemical stability, optical transparency, magnetic transparency and biological compatibility. Therefore, the combination of SiO2 and lead halide perovskite to prepare core-shell structure nanocrystals can have the advantages of both, and has a wide range of applications in catalysis, biomedicine and other fields. Wang et al. Directly mixed CsPbBr3 nanocrystals with mesoporous silica with a pore size of about 12-15 nm to prepare CsPbBr3@SiO2 core-shell structure nanocrystals, and the synthesis process is shown in Figure 6 (a)[70]. The coated sample has excellent thermal stability and light stability: the fluorescence intensity of the sample before and after heat treatment at 100 ℃ is almost unchanged, while that of the uncoated sample is only 60% of the original intensity; After 96 H of continuous UV (365 nm, 6 W) irradiation, the fluorescence intensity was still 80% of that before light treatment, and only 40% of that of the uncoated sample. Dirin et al. infiltrated the perovskite precursor solution into the mesoporous SiO2 and crystallized it to obtain CsPbBr3@SiO2 core-shell structure nanocrystals. It is noteworthy that this method can control the size of the lead halide perovskite nanocrystals by controlling the pore size of the mesoporous SiO2, thus not only improving the stability of the nanocrystals, but also significantly improving their size uniformity[71].
In addition to direct mixing, the slow hydrolysis and polycondensation of organosilane to obtain a SiO2 coating is also an effective method to prepare CsPbBr3@SiO2 core-shell structure nanocrystals. Sun et al. Used 3-aminopropyltriethoxysilane (APTES) as both the ligand and silicon source of the lead halide perovskite nanocrystals. First, the lead halide perovskite nanocrystals were synthesized in an anhydrous system, and then APTES was hydrolyzed with trace water in the air to form a SiO2 coating on the surface of the nanocrystals[72]. This method has the following obvious advantages: (1) APTES is helpful to dissolve the amino group in the precursor PbX2;(2)APTES, which can passivate the surface of the nanocrystal and effectively improve its PLQY; (3) three silyl ethers of APTES can hydrolyze to form a cross-linked SiO2 matrix covering the surface of the nanocrystal, thereby improving the stability of nanocrystals. Guan et al. injected the lead halide perovskite precursor into APTES, and directly synthesized CsPbBr3@SiO2 core-shell structure nanocrystals at room temperature. The hydrolysis of APTES to form the SiO2 shell took only 20 s, and the synthesis process is shown in Figure 6 (C)[73]. The PLQY of the nanocrystal is 75%, and the color temperature (CCT) of the white LEDs is 3689 K, and the luminous efficiency is 40.6 lm·W-1. Hu et al. prepared CsPbBr3@SiO2 core-shell structure nanocrystals by mixing tetraethyl orthosilicate (TEOS) with CsPbBr3 nanocrystals, which have good luminescence intensity, no light flicker and excellent light stability[74]. Park et al. Used perhydropolysilazane (PHPS) as a silicon precursor to grow SiO2 shells on CsPbBr3 nanocrystals in a humid environment, which improved the thermal and chemical stability of the nanocrystals[75]. Compared with large agglomerates, CsPbBr3@SiO2 core-shell nanocrystals with simple preparation and high stability have great potential applications in high-quality thin films, biological imaging and many other fields.
In addition to SiO2, inorganic metal oxides such as TiO2 and Al2O3 have gradually entered the field of scientific researchers because of their excellent stability. Li et al. Wrapped CsPbBr3 nanocrystals with titanium precursor and calcined at high temperature to obtain CsPbBr3@TiO2 core-shell structure nanocrystals, as shown in Figure 7. The stability of the wrapped nanocrystals was greatly improved[76]. Compared with the organic matrix as a coating layer, the TiO2 shell layer not only effectively protects the nanocrystals, but also promotes the transport of charge carriers; Yuan et al. Directly grew CsPbBr3 nanocrystals in TeO2 glass, and the coated nanocrystals could maintain 90% of the original fluorescence intensity after being immersed in water for 120 H. Li et al. Coated lead halide perovskite nanocrystals with Al2O3 formed by hydrolysis of trimethylaluminum (TMA) to improve their photothermal stability, thereby improving the overall performance of QLED devices[77][78]. Loiudice et al. Prepared CsPbBr3@AlOx nanocrystals by atomic layer deposition (ALD). Amorphous alumina directly grew on the surface of lead halide perovskite nanocrystals, which showed excellent stability to air, high-energy light radiation, heat and water[79]. Recently, You et al. Also used ALD to prepare superstable europium perovskite nanocrystals that can be monodispersed in a polar solvent (boiling water), as shown in fig. 8 (a)[80]. The luminescent intensity of the nanocrystals still remained more than 20% after dispersed in water for 90 days. The stability of the mSiO2-ABX3@AlOx dispersed in water is influenced by the thickness of the AlOx shell (fig. 8 (B)), demonstrating that interfacial compatibility plays an important role in the formation of compact protective shells. The combination of SiO2 and AlOx reduces the pinhole defects that often occur with coating alone, resulting in lower water oxygen permeability[81]. Due to the inhibition of ion exchange, a wide color gamut can be easily achieved by mixing lead halide perovskite nanocrystals, which broadens the application of nanocrystals in the field of optoelectronics.

3.3 Inorganic non-oxide matrix coating

The stability of perovskite nanocrystals can also be improved by coating them with a dense inorganic non-oxide matrix. Guhrenz et al. added CsPbBr3 nanocrystals to KX (X = Cl, Br, I) salt under high pressure (Fig. 9 (a)), and the quantum yield of the prepared CsPbBr3@KX microspheres remained unchanged after 7 days of exposure to air, and remained 50% of the initial quantum yield after 14 days[82]. Lou et al. Prepared CsPbBr3@NH4Br core-shell nanocrystals by ion exchange (Figure 9(b)),NH4Br, which can block the contact between nanocrystals and water in the environment, while [NH4]+ improves the stability of nanocrystals in polar solvents[83]. Yu et al. Used the supersaturation recrystallization method to grow a Pb (OH) Br layer on the surface of low-dimensional halide perovskite (RDP) (Fig. 9 (C)), and the formed RDP @ Pb (OH) Br core-shell nanocrystals have excellent chemical, thermal and optical stability, while effectively avoiding anion exchange[84].
Coating perovskite nanocrystals with semiconductor materials is also one of the effective means to passivate the surface of nanocrystals and improve their optical properties and stability. In this kind of core-shell structure semiconductor nanocrystals, the band gap of the shell material is wider than that of the core material, so electrons and holes are confined in the core, which effectively inhibits non-radiative recombination[85]. In 2019, Tang et al. Grown CdS shell on the surface of CsPbBr3 nanocrystals by thermal injection method, and obtained CsPbBr3@CdS core-shell perovskite nanocrystals[86]. The nanocrystal has good optical performance and stability, and the QLED device prepared by using the nanocrystal has the maximum brightness of 354 cd·m-2, the current efficiency of 0.3 cd·A-1, and the best external quantum efficiency of 5.4 times of that before coating. Quan et al. First embedded CsPbBr3 into stable Cs4PbBr6 nanocrystals, and the smaller lattice matching degree between CsPbBr3 and Cs4PbBr6 is conducive to passivating surface defects.Meanwhile, the CsPbBr3 nanocrystals are dispersed in the Cs4PbBr6 phase to avoid fluorescence quenching caused by agglomeration, thereby realizing the high luminous efficiency of the nanocrystals[87]. Xuan et al. generated the Cs4PbBr6 phase in situ during the synthesis of the CsPbBr3 nanocrystal by the improved supersaturation recrystallization method (Fig. 10), and formed the CsPbBr3@Cs4PbBr6 composite nanocrystal. From Fig. 10 (B), it can be seen that the luminescent performance of the CsPbBr3@Cs4PbBr6 composite nanocrystal is significantly better than that of the pure CsPbBr3 nanocrystalline, and at the same time, it effectively improves the stability of the nanocrystalline and solves the problem of fluorescence quenching of perovskite nanocrystals[88].
In summary, the use of hydrophobic or dense organic/inorganic matrix materials to coat the all-inorganic gadolinium-lead-halide perovskite nanocrystals is an effective means to isolate them from air, water and polar solvents and improve their stability. Among them, organic polymer matrix has the advantages of high flexibility and processability, but its high temperature stability is poor. Metal-organic frameworks (MOFs) are characterized by high porosity and stability, but it is difficult to control the size of composite nanocrystals. Inorganic oxide matrix has strong stability, weak water and oxygen permeability, and has the obvious advantage of crystal transparency, but its preparation process is complex. The inorganic non-oxide matrix has superior thermal stability, compact structure, and stability, but large size and lattice constraints. Table 1 shows the effect of different core-shell materials on the stability of all-inorganic cesium-lead-halide perovskite nanocrystals.

4 Application of All-inorganic Cesium Lead Halogen Perovskite Nanocrystals in WLED Field

Light-emitting diodes (LEDs) are solid-state semiconductor devices that directly convert electrical energy into visible light when driven by a voltage. Compared with xenon, fluorescent and incandescent lamps on the market, LEDs have the advantages of non-toxicity, low power requirements, fast response and long service life[92⇓~94]. Semiconductor nanocrystals can be integrated into LEDs as efficient excitonic radiative recombination centers by solution processing, spin coating, and inkjet printing[95].
Quantum dot light emitting diodes (QLEDs) have attracted wide attention in the field of liquid crystal displays (LCDs), which break through the inherent limitations of traditional LCDs, such as light leakage, low contrast, poor viewing angle and slow response speed. However, at present, QLEDs have the disadvantages of poor thermal stability and being easily affected by humidity. Due to the wide luminescent color gamut of all-inorganic cesium lead halide perovskite nanocrystals and the greatly improved stability after coating, as shown in Table 2, QLEDs with better performance can be obtained.
White light emitting diode (WLED) is a kind of light source with low power, good mechanical strength, high light efficiency, energy saving and environmental protection. As shown in Figure 11, WLED is mainly composed of LED chips and one or more fluorescent materials, and can be used in the field of lighting. At present, most of the fluorescent materials widely used in WLEDs on the market are rare earth doped phosphors with wide emission spectra, which need to be filtered to display the required monochromatic light. However, light filtering will cause energy waste and increase the difficulty of manufacturing[97]. The adoption of the phosphor with the narrow emission spectrum can enlarge the color gamut of the display, improve the color display saturation and improve the energy utilization efficiency[98].
All-inorganic cesium-lead halide perovskite nanocrystals are considered as an ideal substitute for rare earth doped phosphors due to their narrow emission spectra, high PLQY and short fluorescence lifetime[99,100].
Huang et al. Synthesized CsPbX3@POSS using polyhedral oligomeric silsesquioxane (POSS), which improved the stability of nanocrystals[62]. The WLEDs prepared by the coated nanocrystals have good performance, the CIE coordinates are (0.349, 0.383), the CRI value is 81, and the fluorescence efficiency is 14.1 lm·W-1. Di et al. Prepared CsPbBr3@MS nanocrystals by mixing Mesoporous Silica (MS) with CsPbBr3 nanocrystals and stirring in toluene[101]. The thermal stability, light stability and storage stability of the coated nanocrystals are obviously improved. After mixing the CsPbBr3@MS nanocrystals and Sr2Si5N8:Eu2+ red phosphors, a white light emitting diode (WLED) was fabricated on an InGaN blue chip.The CIE coordinates of the device were (0. 3365,0.3390), the luminous efficiency was 47.6 lm·W-1, the color rendering index was 72. 3, and the correlated color temperature was 5318 K. When the driving current is changed, the device still exhibits good color stability.
Park et al. Used perhydropolysilazane (PHPS) as a silicon precursor, and prepared CsPbBr3@SiO2 core-shell nanocrystals by hydrolyzing PHPS to generate SiO2 in a humid environment[75]. The thermal stability and the chemical stability of the nanocrystal are greatly improved. The nanocrystals were mixed with CsPbBr1.2I1.8 and coated on a blue led chip to fabricate a WLED device. The luminescent efficiency of the device is 35.4 lm·W-1, the correlated color temperature is 5623 K, and the anion exchange phenomenon is not observed. When the device was driven by a current of 20 mA, it emitted bright white light, and three distinct emission peaks were observed in the blue, green and red spectral regions, respectively, which indicated that the SiO2 shell formed by the hydrolysis of PHPS effectively prevented the anion exchange between the Br- and the I-. The CIE coordinates of the device are (0.3295, 0.3592), and the device has a wider color gamut (127% NTSC) compared with the WLED device prepared by the CsPbBr3 nanocrystal, showing excellent color reproducibility.
Zhou et al. prepared superhydrophobic CsPbBr3 nanocrystals coated with organosilicon particles by a two-step synthesis method, which effectively isolated the contact between the nanocrystals and the outside world, avoided the degradation of the nanocrystals in a humid environment, and also isolated the direct contact between the nanocrystalline to prevent the fluorescence quenching caused by the agglomeration of the nanocrystalline[91]. The WLEDs prepared by mixing the core-shell structure nanocrystals and the YAG(CaAlSiN3:Eu2+) have good optical performance, the CIE coordinates are (0.33, 0.33), the CRI value is 54.3, and the fluorescence efficiency is 22.6 lm·W-1, so that the WLEDs have good prospects in the field of illumination and display. Hu et al. mixed CsPbBr3@SiO2 core-shell nanocrystals with CdSe @ PMMA and coated them on blue chips to prepare WLED devices[90]. Under the driving current of 2 mA, the device has a CIE coordinate of (0.30, 0.32), a CRI of 63, an EQE of 16.14%, a luminous efficiency of 56 lm·W-1, and a wide color gamut (138% NTSC). Compared with the uncoated nanocrystals, the CsPbBr3@SiO2 nanocrystals have better optical stability, so the prepared WLEDs also show excellent optical stability (Fig. 12), and the color coordinates are still in the white region after 1 H. In contrast, the light stability of the device prepared by the uncoated CsPbBr3 is poor, the green emission peak shown in the CIE coordinate diagram is gradually weakened, and the luminescence of the prepared WLED changes from white to blue.
Zhang et al. encapsulated CsPbX3(X=Br, Br1.2/I1.8) into a Zr-based stabilized metal organic framework (Uio-67), and CsPbX3@Uio-67 nanocrystals have excellent photoluminescence properties and stability[89]. WLEDs fabricated using CsPbX3@Uio-67 and K2SiF6:Mn4+ have a very wide color gamut (138% NTSC) and a wide color gamut (4082 K).
The optical and electrical property of that WLEDs based on the core-shell structure all-inorganic cesium lead halide perovskite nanocrystal are summarized in Table 3.

5 Conclusion and prospect

All-inorganic cesium lead halide perovskite semiconductor nanocrystals have the advantages of continuously tunable emission wavelength in the visible light range, high color saturation, high fluorescence quantum yield and batch preparation, and have wide application prospects in the fields of light-emitting diodes, solar cells and biological imaging. With the in-depth study of the luminescence mechanism, doping mechanism, preparation methods and optoelectronic applications of nanocrystals, a large number of nanocrystals with high efficiency have been reported, but due to their high ionic characteristics, the optical and thermal stability of nanocrystalline still needs to be improved. At present, the stability of all-inorganic perovskite materials can be effectively improved by various strategies such as ion doping, surface modification and surface coating. Among them, the surface coating method can not only directly isolate the nanocrystals from the environment, but also avoid the anion exchange process, so it has great application prospects in the field of WLED. However, there are still some problems to be solved in the coating process, for example, the growth of the coating matrix on the surface of the nanocrystals will damage the original ligands[77]; How to realize the uniform coating of nanocrystals without damaging the optical properties; When applied in the field of WLEDs, the light transmittance, the light efficiency, the color rendering index and the like of the wrapping layer are improved. In a word, the study of all-inorganic Cesium Lead Halogen Perovskite semiconductor nanocrystals with high performance and stability will have a profound impact on the scientific research and commercial applications of fluorescent materials.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]

Peña M A, Fierro J L G. Chem. Rev., 2001, 101(7): 1981.
[2]

Kim H S, Lee C R, Im J H, Lee K B, Moehl T, Marchioro A, Moon S J, Humphry-Baker R, Yum J H, Moser J E, Grätzel M, Park N G. Sci. Rep., 2012, 2(1): 1.
[3]

Lee M M, Teuscher J, Miyasaka T, Murakami T N, Snaith H J. Science, 2012, 338(6107): 643.
[4]

Stranks S D, Snaith H J. Nat. Nanotechnol., 2015, 10(5): 391.
[5]

Schmidt L C, Pertegás A, González-Carrero S, Malinkiewicz O, Agouram S, Mínguez Espallargas G, Bolink H J, Galian R E, Pérez-Prieto J. J. Am. Chem. Soc., 2014, 136(3): 850.
[6]

Dave K, Bao Z, Nakahara S, Ohara K, Masada S, Tahara H, Kanemitsu Y, Liu R S. Nanoscale, 2020, 12(6): 3820.
[7]

Xu Y, Lou S Q, Xia C, Xuan T T, Li H L. J. Lumin., 2020, 222: 117132.
[8]

Li Q, Wang H B, Yue X F, Du J X. Talanta, 2020, 211: 120705.
[9]

Zhang H L, Yuan L, Chen Y, Zhang Y Q, Yu Y X, Liang X J, Xiang W D, Wang T. Chem. Commun., 2020, 56(19): 2853.
[10]

Liu X Y, Liu Z Y, Li J J, Tan X H, Sun B, Fang H, Xi S, Shi T L, Tang Z R, Liao G L. J. Mater. Chem. C, 2020, 8(10): 3337.
[11]

Zhu W D, Deng M Y, Chen D D, Chen D Z, Xi H, Chang J J, Zhang J C, Zhang C F, Hao Y. J. Mater. Chem. C, 2020, 8(1): 209.
[12]

Chen Y X, Xu Y F, Wang X D, Chen H Y, Kuang D B. Sustain. Energy Fuels, 2020, 4(5): 2249.
[13]

Huang H, Bodnarchuk M I, Kershaw S V, Kovalenko M V, Rogach A L. ACS Energy Lett., 2017, 2(9): 2071.
[14]

Zou S H, Liu Y S, Li J H, Liu C P, Feng R, Jiang F L, Li Y X, Song J Z, Zeng H B, Hong M C, Chen X Y. J. Am. Chem. Soc., 2017, 139(33): 11443.
[15]

Krieg F, Ochsenbein S T, Yakunin S ten Brinck S, Aellen P, Süess A, Clerc B, Guggisberg D, Nazarenko O, Shynkarenko Y, Kumar S, Shih C J, Infante I, Kovalenko M V. ACS Energy Lett., 2018, 3(3): 641.
[16]

Bodnarchuk M I, Boehme S C, ten Brinck S, Bernasconi C, Shynkarenko Y, Krieg F, Widmer R, Aeschlimann B, Günther D, Kovalenko M V, Infante I. ACS Energy Lett., 2019, 4(1): 63.
[17]

Ding N, Zhou D L, Sun X K, Xu W, Xu H W, Pan G C, Li D Y, Zhang S, Dong B, Song H W. Nanotechnology, 2018, 29(34): 345703.
[18]

Ma T Q, Wang S W, Zhang Y W, Zhang K X, Yi L X. J. Mater. Sci., 2020, 55(2): 464.
[19]

Kojima A, Teshima K, Shirai Y, Miyasaka T. J. Am. Chem. Soc., 2009, 131(17): 6050.
[20]

Stoumpos C C, Kanatzidis M G. Acc. Chem. Res., 2015, 48(10): 2791.
[21]

Knop O, Wasylishen R E, White M A, Cameron T S, Oort M J M V. Can. J. Chem., 1990, 68(3): 412.
[22]

Evarestov R A, Kotomin E A, Senocrate A, Kremer R K, Maier J. Phys. Chem. Chem. Phys., 2020, 22(7): 3914.
[23]

Burwig T, Fränzel W, Pistor P. J. Phys. Chem. Lett., 2018, 9(16): 4808.
[24]

Yi C Y, Luo J S, Meloni S, Boziki A, Ashari-Astani N, Grätzel C, Zakeeruddin S M, Röthlisberger U, Grätzel M. Energy Environ. Sci., 2016, 9(2): 656.
[25]

Møller C K. Nature, 1958, 182(4647): 1436.
[26]

Brivio F, Walker A B, Walsh A. APL Mater., 2013, 1(4): 042111.
[27]

Kovalenko M V, Protesescu L, Bodnarchuk M I. Science, 2017, 358(6364): 745.
[28]

Brandt R E, Stevanović V, Ginley D S, Buonassisi T. MRS Commun., 2015, 5(2): 265.
[29]

Kang J, Wang L W. J. Phys. Chem. Lett., 2017, 8(2): 489.
[30]

Palazon F, Akkerman Q A, Prato M, Manna L. ACS Nano, 2016, 10(1): 1224.
[31]

Palazon F di Stasio F, Akkerman Q A, Krahne R, Prato M, Manna L. Chem. Mater., 2016, 28(9): 2902.
[32]

Kothandaraman R K, Jiang Y, Feurer T, Tiwari A N, Fu F. Small Methods, 2020, 4(10): 2000395.
[33]

Zhu H, Miyata K, Fu Y, Wang J, Joshi P P, Niesner D, Williams K W, Jin S, Zhu X Y. Science, 2016, 353(6306): 1409.
[34]

Bakulin A A, Selig O, Bakker H J, Rezus Y L A, Müller C, Glaser T, Lovrincic R, Sun Z H, Chen Z Y, Walsh A, Frost J M, Jansen T L C. J. Phys. Chem. Lett., 2015, 6(18): 3663.
[35]

Huang S Q, Li Z C, Wang B, Zhu N W, Zhang C Y, Kong L, Zhang Q, Shan A D, Li L. ACS Appl. Mater. Interfaces, 2017, 9(8): 7249.
[36]

Dai J F, Xi J, Zu Y Q, Li L, Xu J, Shi Y F, Liu X Y, Fan Q H, Zhang J J, Wang S P, Yuan F, Dong H, Jiao B, Hou X, Wu Z X. Nano Energy, 2020, 70: 104467.
[37]

Kim Y, Yassitepe E, Voznyy O, Comin R, Walters G, Gong X W, Kanjanaboos P, Nogueira A F, Sargent E H. ACS Appl. Mater. Interfaces, 2015, 7(45): 25007.
[38]

de Roo J, Ibáñez M, Geiregat P, Nedelcu G, Walravens W, Maes J, Martins J C, van Driessche I, Kovalenko M V, Hens Z. ACS Nano, 2016, 10(2): 2071.
[39]

Creutz S E, Crites E N, de Siena M C, Gamelin D R. Nano Lett., 2018, 18(2): 1118.
[40]

Roesch R, Faber T, von Hauff E, Brown T M, Lira-Cantu M, Hoppe H. Adv. Energy Mater., 2015, 5(20): 1501407.
[41]

Ren J J, Dong X, Zhang G Y, Li T R, Wang Y H. New J. Chem., 2017, 41(22): 13961.
[42]

Diroll B T, Nedelcu G, Kovalenko M V, Schaller R D. Adv. Funct. Mater., 2017, 27(21): 1606750.
[43]

Amgar D, Binyamin T, Uvarov V, Etgar L. Nanoscale, 2018, 10(13): 6060.
[44]

Rao L S, Tang Y, Yan C M, Li J S, Zhong G S, Tang K R, Yu B H, Li Z T, Zhang J Z. J. Mater. Chem. C, 2018, 6(20): 5375.
[45]

Shi J D, Ge W Y, Zhu J F, Saruyama M, Teranishi T. ACS Appl. Nano Mater., 2020, 3(8): 7563.
[46]

Huang S Q, Wang B, Zhang Q, Li Z C, Shan A D, Li L. Adv. Opt. Mater., 2018, 6(6): 1701106.
[47]

Li S, Shi Z F, Zhang F, Wang L T, Ma Z Z, Yang D W, Yao Z Q, Wu D, Xu T T, Tian Y T, Zhang Y T, Shan C X, Li X J. Chem. Mater., 2019, 31(11): 3917.
[48]

Lv W, Li L, Xu M C, Hong J X, Tang X X, Xu L G, Wu Y H, Zhu R, Chen R F, Huang W. Adv. Mater., 2019, 31(28): 1900682.
[49]

Wu L Z, Zhong Q X, Yang D, Chen M, Hu H C, Pan Q, Liu H Y, Cao M H, Xu Y, Sun B Q, Zhang Q. Langmuir, 2017, 33(44): 12689.
[50]

Pan L, Zhang L, Qi Y F, Conkle K, Han F X, Zhu X C, Box D, Shahbazyan T V, Dai Q L. ACS Appl. Nano Mater., 2020, 3(9): 9260.
[51]

Chen T, Xu Y Q, Xie Z X, Jiang W H, Wang L J, Jiang W. Nanoscale, 2020, 12(17): 9569.
[52]

Henglein A. Chem. Rev., 1989, 89(8): 1861.
[53]

Zhou H S, Sasahara H, Honma I, Komiyama H, Haus J W. Chem. Mater., 1994, 6(9): 1534.
[54]

Brokmann X, Messin G, Desbiolles P, Giacobino E, Dahan M, Hermier J P. New J. Phys., 2004, 6: 99.
[55]

Marchuk K, Guo Y J, Sun W, Vela J, Fang N. J. Am. Chem. Soc., 2012, 134(14): 6108.
[56]

Jiang D H, Tsai Y H, Veeramuthu L, Liang F C, Chen L C, Lin C C, Satoh T, Tung S H, Kuo C C. APL Mater., 2019, 7(11): 111105.
[57]

Zhong Q X, Cao M H, Hu H C, Yang D, Chen M, Li P L, Wu L Z, Zhang Q. ACS Nano, 2018, 12(8): 8579.
[58]

Protesescu L, Yakunin S, Bodnarchuk M I, Krieg F, Caputo R, Hendon C H, Yang R X, Walsh A, Kovalenko M V. Nano Lett., 2015, 15(6): 3692.
[59]

Hormats E I, Unterleitner F C. J. Phys. Chem., 1965, 69(11): 3677.
[60]

Müller M, Kaiser M, Stachowski G M, Resch-Genger U, Gaponik N, Eychmüller A. Chem. Mater., 2014, 26(10): 3231.
[61]

Zhang H H, Wang X, Liao Q, Xu Z Z, Li H Y, Zheng L M, Fu H B. Adv. Funct. Mater., 2017, 27(7): 1604382.
[62]

Huang H, Chen B K, Wang Z G, Hung T F, Susha A S, Zhong H Z, Rogach A L. Chem. Sci., 2016, 7(9): 5699.
[63]

Xuan T T, Huang J J, Liu H, Lou S Q, Cao L Y, Gan W J, Liu R S, Wang J. Chem. Mater., 2019, 31(3): 1042.
[64]

Wei Y, Deng X R, Xie Z X, Cai X C, Liang S S, Ma P A, Hou Z Y, Cheng Z Y, Lin J. Adv. Funct. Mater., 2017, 27(39): 1703535.
[65]

Ren J J, Zhou X P, Wang Y H. Chem. Eng. J., 2020, 391: 123622.
[66]

Furukawa H, Cordova K E, O'Keeffe M, Yaghi O M. Science, 2013, 341(6149): 1230444.
[67]

James S L. Chem. Soc. Rev., 2003, 32(5): 276.
[68]

Li Z X, Yu C C, Wen Y Y, Wei Z T, Chu J M, Xing X F, Zhang X, Hu M L, He M. Nanomaterials, 2019, 9(8): 1147.
[69]

Li Z C, Kong L, Huang S Q, Li L. Angew. Chem. Int. Ed., 2017, 56(28): 8134.
[70]

Wang H C, Lin S Y, Tang A C, Singh B P, Tong H C, Chen C Y, Lee Y C, Tsai T L, Liu R S. Angew. Chem. Int. Ed., 2016, 55(28): 7924.
[71]

Dirin D N, Protesescu L, Trummer D, Kochetygov I V, Yakunin S, Krumeich F, Stadie N P, Kovalenko M V. Nano Lett., 2016, 16(9): 5866.
[72]

Sun C, Zhang Y, Ruan C, Yin C Y, Wang X Y, Wang Y D, Yu W W. Adv. Mater., 2016, 28(45): 10088.
[73]

Guan H L, Zhao S Y, Wang H X, Yan D D, Wang M, Zang Z G. Nano Energy, 2020, 67: 104279.
[74]

Hu Z P, Liu Z Z, Bian Y, Li S Q, Tang X S, Du J, Zang Z G, Zhou M, Hu W, Tian Y X, Leng Y X. Adv. Opt. Mater., 2018, 6(3): 1700997.
[75]

Park D H, Han J S, Kim W, Jang H S. Dyes Pigments, 2018, 149: 246.
[76]

Li Z J, Hofman E, Li J, Davis A H, Tung C H, Wu L Z, Zheng W W. Adv. Funct. Mater., 2018, 28(1): 1704288.
[77]

Yuan S, Chen D Q, Li X Y, Zhong J S, Xu X H. ACS Appl. Mater. Interfaces, 2018, 10(22): 18918.
[78]

Li G R, Rivarola F W R, Davis N J L K, Bai S, Jellicoe T C, de la Peña F, Hou S C, Ducati C, Gao F, Friend R H, Greenham N C, Tan Z K. Adv. Mater., 2016, 28(18): 3528.
[79]

Loiudice A, Saris S, Oveisi E, Alexander D T L, Buonsanti R. Angew. Chem. Int. Ed., 2017, 56(36): 10696.
[80]

You C Y, Li F M, Lin L H, Lin J S, Chen Q Q, Radjenovic P M, Tian Z Q, Li J F. Nano Energy, 2020, 71: 104554.
[81]

Dameron A A, Davidson S D, Burton B B, Carcia P F, McLean R S, George S M. J. Phys. Chem. C, 2008, 112(12): 4573.
[82]

Guhrenz C, Benad A, Ziegler C, Haubold D, Gaponik N, Eychmüller A. Chem. Mater., 2016, 28(24): 9033.
[83]

Lou S Q, Xuan T T, Yu C Y, Cao M M, Xia C, Wang J, Li H L. J. Mater. Chem. C, 2017, 5(30): 7431.
[84]

Yu Y C, Hou J H, Zhang L H, Sun Q S, Attique S, Wang W J, Xu X X, Xu F, Ci Z P, Cao B Q, Qiao X, Xiao X H, Yang S K. Nano Lett., 2020, 20(4): 2316.
[85]

García-Santamaría F, Brovelli S, Viswanatha R, Hollingsworth J A, Htoon H, Crooker S A, Klimov V I. Nano Lett., 2011, 11(2): 687.
[86]

Tang X S, Yang J, Li S Q, Chen W W, Hu Z P, Qiu J. Front. Chem., 2019, 7: 499.
[87]

Quan L N, Quintero-Bermudez R, Voznyy O, Walters G, Jain A, Fan J Z, Zheng X L, Yang Z Y, Sargent E H. Adv. Mater., 2017, 29(21): 1605945.
[88]

Xuan T T, Lou S Q, Huang J J, Cao L Y, Yang X F, Li H L, Wang J. Nanoscale, 2018, 10(21): 9840.
[89]

Zhang D W, Zhao J, Liu Q L, Xia Z G. Inorg. Chem., 2019, 58(2): 1690.
[90]

Hu H C, Wu L Z, Tan Y S, Zhong Q X, Chen M, Qiu Y H, Yang D, Sun B Q, Zhang Q, Yin Y D. J. Am. Chem. Soc., 2018, 140(1): 406.
[91]

Zhou Y J, Pan A Z, Shi C Y, Ma X Q, Jia M J, Huang H, Ren D Z, He L. Appl. Surf. Sci., 2020, 515: 146004.
[92]

Narukawa Y, Ichikawa M, Sanga D, Sano M, Mukai T. J. Phys. D: Appl. Phys., 2010, 43(35): 354002.
[93]

Mishra K C, Zachau M, Levin R E. Phys. Rev. Lett., 2009, 103(26): 269401.
[94]

Narendran N, Gu Y. J. Display Technol., 2005, 1(1): 167.
[95]

Maier-Flaig F, Rinck J, Stephan M, Bocksrocker T, Bruns M, Kübel C, Powell A K, Ozin G A, Lemmer U. Nano Lett., 2013, 13(2): 475.
[96]

Jiang G C, Guhrenz C, Kirch A, Sonntag L, Bauer C, Fan X L, Wang J, Reineke S, Gaponik N, Eychmüller A. ACS Nano, 2019, 13(9): 10386.
[97]

Hao W, Xinmin Z, Chongfeng G, Jian X, Mingmei W, Qiang S. IEEE Photonics Technol. Lett., 2005, 17(6): 1160.
[98]

Shirasaki Y, Supran G J, Bawendi M G, Bulović V. Nat. Photonics, 2013, 7(1): 13.
[99]

Li X M, Wu Y, Zhang S L, Cai B, Gu Y, Song J Z, Zeng H B. Adv. Funct. Mater., 2016, 26(15): 2435.
[100]

Filippetti A, Mattoni A. Phys. Rev. B, 2014, 89(12): 125203.
[101]

Di X X, Shen L D, Jiang J T, He M L, Cheng Y Z, Zhou L, Liang X J, Xiang W D. J. Alloys Compd., 2017, 729: 526.
[102]

Li G G, Tian Y, Zhao Y, Lin J. Chem. Soc. Rev., 2015, 44(23): 8688.

Funding

National Natural Science Foundation of China(52062019)

Qinglan Praject of Jiangsu Province, and the Project of Jingdezhen Science and Technology Bureau(20192GYZD008-15)

Qinglan Praject of Jiangsu Province, and the Project of Jingdezhen Science and Technology Bureau(20192GYZD008-18)

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