Enhanced Performance Of Sb₂Se₃ Thin-film Solar Cells By Introducing Small Organic Molecules Buffer Layer

Thin film solar cells are the second generation of solar cells after crystalline silicon cells.Thin films can be deposited on flexible substrates.The device has many attractive properties such as less materials,low cost,light weight and convenient for large-scale production.Hence,thin film solar cell can significantly reduce the cost of photovoltaic power generation.Antimony selenide（Sb₂Se₃）is a rising photovoltaic material.It has many attractive properties such as suitable bandgap,high absorption coefficient,simple binary phase,earth-abundant constituents and low price,which has attracted much attention in the field of thin film solar cells.Though the great improvements have been achieved,the efficiency is much lower than its theoretical limit.It can not be compared with silicon,cadmium telluride,copper indium gallium selenide solar cells.A lot of research is required to improve the performance of antimony selenide solar cells.In this paper,we introduce small organic molecule to the Sb₂Se₃ solar cell as a buffer layer to enhance the device performance.In chapter 3,we introduce an organic metal complex of Ir（ppy）₃ to the Sb₂Se₃ solar cell as a buffer layer.The structure of ITO/Ir（ppy）₃/Sb₂Se₃/C₆₀/Al Q/Al device was prepared.The results show that the crystal quality of antimony selenide thin films was improved by Ir（ppy）₃buffer layer.Shockley-Read-Hall（SRH）recombination occurring in the device was inhibited.The open-circuit voltage was increased from 0.33 V to 0.40 V,the short-circuit current density was raised from 19.8 m A cm^-2 to 21.2 m A cm^-2,and the photoelectric conversion efficiency was improved from 3.3%to 4.8%.In chapter 4,we introduce the small organic molecule Rubrene to the Sb₂Se₃ solar cell as a buffer layer and select Cd S as the electron transport layer.The structure of ITO/Rubrene/Sb₂Se₃/Cd S/Al Q/Al device was prepared.The results show that the interface recombination was inhibited by Rubrene.The open-circuit voltage was increased from 0.28 V to 0.30 V,the short-circuit current density was raised from 11.1 m A cm^-2 to 14.0 m A cm^-2,and the photoelectric conversion efficiency was improved from 1.4%to 2.1%after the introduction of Rubrene.