Analysis of The Efficiency In Sb2Se3 Thin-Film Solar Cells Using Alternative Buffer Layers In n-p and n-i-p Structures By Numerical Simulation.

Antimony Sulfide (Sb2Se3) Solar Cells are considered a promising emerging photovoltaic devices technology. However, the best reported experimental efficiency (9.2%) is well below the theoretical limit of 30%. In this research is demonstrated, by numerical simulation, that using different buffer or electron transport layers (ETL) and device structures (n-p or n-i-p) can significantly increase the solar cell performance. The study is based on two underlying considerations: the use of inorganic materials to facilitate the manufacturing process and the analysis of the simulation parameters that adjust to the experimental conditions in which the cells can be processed. In the n-p structures, the use of single layers and bilayers as ETL was evaluated and the possible mechanism that explain the electrical parameters of the solar cell were discussed. Especial attention was made in the role of interfacial state density and band alignment in the ETL/Sb2Se3 interface. In addition, the n-i-p structure was studied by adding a hole transport layer (HTL). An improvement in open circuit voltage (Voc) is observed compared with n-p structure. Finally, the behavior of Voc and efficiency vs thickness of the ETL and Sb2Se3 layers was analyzed. The results show that using alternative ETLs a significant improve in Voc and efficiency could be achieved for n-p and n-i-p structures. After thickness optimization and taking account a moderate interface defect density, values of Voc and efficiency higher than 600 mV and 15 % were respectively obtained.