For the whole solution-processed efficient and stable organic photovoltaic devices at low temperature, reasonably selecting the method of interface modification material preparation is very crucial. It has become one of the most focuses in research community of organic photovoltaics in recent years. By choosing suitable interfacial materials, the energetic barrier height at the interface could be reduced to form an ohmic contact with less series resistance, inducing high charge collection efficiency of the corresponding electrodes for holes or electrons. Solution-prepared molybdenum oxide (MoO₃) as anode buffer layer can effectively improve the efficiency of interface collection and carrier transmission, improving the energy conversion efficiency and stability of organic solar cells. This article reviews the research progress of anode buffer layer MoO₃ of organic solar cells in recent years, introduces the some preparation methods and principles of MoO₃ as anode interface layers, elaborated the current situation and existing problems of MoO₃ film based on the prepared solution of interfacial modification, which provides valuable references for the fabrication of the efficient and stable organic solar cells. We believe that solution-processed MoO₃ will play a key role as buffer layers in the future fabrication of large area and flexible organic photovoltaic devices with high performance and long term stability.

Contents
1 Introduction
2 The effect of solution-prepared of MoO₃ anode interface modification
3 The energy level structure and change of MoO₃
4 The application of solution-prepared MoO₃ in organic solar cell
4.1 MoO₃ based on the preparation of ammonium molybdate
4.2 MoO₃ based on organic molybdenum sources
4.3 MoO₃ prepared by chemical synthesis
4.4 MoO₃ prepared by nanoparticle dispersion method
4.5 MoO₃ prepared by other solutions
5 Conclusion