Abstract
•The main presented design is a p-n homojunction configuration of Sb2Se3 solar cells (SCs)•In contrast to the heterostructure design, the presented design has crucial benefits in terms of electronic and optoelectronic characteristics.•The work utilizes calibration and extraction of material parameters based on experimental studies.•The optimization of different key parameters is performed based on technological constraints.•After optimization, a PCE of 7.75%, 10.08% and 8.79% is obtained for CdS-based, ZnOS-based and homojunction SCs, respectively.
Antimony selenide (Sb2Se3) is considered a promising candidate utilized as an absorber in thin film solar cell (TFSC) technology thanks to its non-toxic and earth-abundant nature besides its reported high absorption coefficient. To enhance the power conversion efficiency (PCE) of Sb2Se3 solar cells, we report some design suggestions by applying device simulation. The numerical model is firstly validated by calibration of simulation results vs those from an experimental Sb2Se3 solar cell structure composed of FTO/CdS/Sb2Se3/Au where CdS serves as an electron transport layer (ETL). Then, the cell is modified to include an embedded p-n homojunction. In contrast to the conventional heterostructure design, a homojunction structure has crucial benefits in terms of both electronic and optoelectronic characteristics such as the extra produced built-in electric field which can increase the transport of photogenerated carriers. Three device configurations are presented and compared. The first and the second cases are when using CdS and ZnOS as ETLs. Utilizing ZnOS ternary compound is found to be more beneficial as its conduction band offset with the absorber layer could be tuned to attain a proper cliff-like band alignment. The third case is when considering homojunction design free from all carrier transport layers. Possible paths for device optimization are investigated to boost the efficiency in a try to overcome the efficiency bottleneck encountered in the Sb2Se3-based quasi homojunction solar cells. All simulations, performed in this study, are done by SCAPS device simulation software under standard AM1.5G one Sun illumination.