Application And Performance Research Of Cu₂ZnSnS₄ Hole Transporting Material In Carbon-based Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cell materials have attracted extensive attention from scholars due to their advantages of high light absorption coefficient and simple preparation process.After ten years of development since 2009,the certification efficiency of single-cell perovskite batteries has reached 25.2%.The laboratory efficiency of perovskite batteries has already reached the standard of commercial production,but its stability and large-scale production problems have always been an obstacle for its commercialization.Among the many structures of perovskite solar cells,the stability of carbon-based perovskite solar cell is particularly excellent.Its non-organic hole transport layer and hydrophobic carbon electrode can greatly improve the stability of the solar cell.The carbon electrode printing process also makes solar cells can be produced commercially in large areas.However,because the carbon-based perovskite solar cell does not contain a hole transport layer,the hole transport capacity of the solar cell is poor,so the solar cell performance is relatively low.In this paper,we introduced the inorganic P-type semiconductor material Cu₂ZnSnS₄（CZTS）into the carbon-based perovskite solar cell as a hole transport layer to improve the photoelectric conversion efficiency of the carbon-based perovskite solar cell.On the premise of its stability,it improves the photoelectric conversion efficiency of the solar cell and provides the possibility of its commercialization.The specific work is as follows:（1）Using CZTS nanocrystals as the hole transport layer to prepare a perovskite solar cell structure of FTO/SnO₂/MAPbI₃/CZTS/Carbon,by optimizing the annealing time and spin coating speed of the CZTS layer.When the annealing time is60min,the spin speed is 4000rpm,the average performance of the carbon-based perovskite solar cell with CZTS as the hole-transporting layer is 12.53%,which is about 50%higher than that of the carbon-based perovskite solar cell without the hole-transporting layer.At the same time,the performance of the carbon-based perovskite solar cell with CZTS as the hole-transporting layer has not deteriorated within 60 days,showing excellent stability.（2）After the ligand exchange treatment of CZTS,as a hole transport layer,the perovskite solar cell with the structure of FTO/TiO₂/MAPbI₃/CZTS/Carbon is prepared.The surface of CZTS synthesized in oleamine contains long-chain oleamine ligands which seriously affects the conductivity of CZTS nanocrystals,making the short circuit current density of carbon-based perovskite solar cells with CZTS as the hole transport layer relatively low.The ligand exchange treatment of CZTS was performed.Compared with the untreated CZTS,the CZTS after ligand exchange treatment had better conductivity and higher hole mobility.The average performance of the perovskite solar cell that using the untreated CZTS as the hole transport layer is14.17%.And the average performance of the perovskite solar cell that using the CZTS after the ligand exchange treatment as the hole transport layer is 16.15%,the best performance is 17.71%,higher than the currently reported best performance of perovskite solar cell using CZTS as the hole transport material.At the same time,the performance of the carbon-based perovskite solar cell with CZTS as the hole-transporting layer was basically not reduced after 30 days,showing excellent stability.