Performance analysis of WSe2-based bifacial solar cells with different electron transport and hole transport materials by SCAPS-1D

In recent years, solar cells made of tungsten diselenide (WSe2) have received comprehensive consideration because of their good photoelectric properties. The planar WSe2-based heterojunction solar cell with a preliminary device structure of Au/WSe2/electron transport layer (ETL)/FTO/Al was designed and investigated numerically by SCAPS-1D. CdS ETL is widely used in thin film solar cells (TFSCs). Due to environmental issues and the low band gap (2.42 eV) of CdS ETL, an alternative to CdS ETL was being explored for WSe2 solar cells. In this work, the photovoltaic (PV) performance of the WSe2-based TFSCs with different ETLs were simulated, analyzed and compared, in an attempt to track down a suitable substitute for the CdS ETL. In addition to CdS ETL, ZnO, TiO2 and SnO2 ETLs were independently used to simulate the PV performance of WSe2-based TCSCs. In the wake of analyzing the J-V curves of different cell configurations, SnO2 ETL yielded the best results with PCE of 27.14 % for the single-junction WSe2/SnO2 TFSC. Then, our simulation predicted that the PV performance of the WSe2 device can be improved significantly by using N doped Cu2O as a hole transport layer (HTL). The optimized WSe2 device with SnO2 ETL and Cu2O:N HTL showed an improved PCE of 33.84 % with very good performance stability at higher temperature. Furthermore, this article proposes to use the Au/Cu2O:N/WSe2/SnO2/FTO/Al heterojunction solar cell in bifacial mode and PV performance of the proposed bifacial device have been also studied using SCAPS-1D. Bifacial WSe2 device leads to enhanced PV performance with bifaciality factor for PCE is 83.64 %. Bifacial gain of the proposed device under simultaneous irradiation of 1 sun from the front and 20 % of 1 sun from back side is found to be 13.95 %. Our simulation predicts that the proposed WSe2 bifacial solar cell is capable of converting solar energy into electricity with an efficiency of about 38.38 %. Bifacial solar cells; Dual-junction solar cells; WSe2 solar cells; Bifaciality factor; Bifacial gain.