Enhancement of the photoconversion efficiency of Sb2S3 based solar cell by overall optimization of electron transport, light harvesting and hole transport layers

In thin-film photovoltaic, Sb2S3 is a leading absorber material due to its broad-band optical response and excellent electrical properties, with the highest reported efficiency in the planar Sb2S3 configuration being 8 %. By simulations, optimized parameters for each component of the n-i-p FTO/ETL/Sb2S3/HTL/Au planar heterojunction device, as well as a photoconversion efficiency (PCE-η) of 28.64 % under an AM 1.5G spectral irradiance, have been predicted. In this report, we systematically optimized the electron transport layer (ETL), light harvesting layer (Sb2S3), and hole transport layer (HTL) separately based on theoretically predicted values in order to understand the effect of each component and optimize solar cell performance. The optimized results showed that simply optimizing the ETL, Sb2S3 layer, and HTL resulted in achieving the efficiency ∼4.11 % and to achieve the theoretically predicted device performance, a precise control of intrinsically formed traps, the presence of surface defect states, and lattice dislocations in Sb2S3, are important as these factors are found to be the main factors that enhance charge carrier recombination, slow charge transfer across the interface, and charge carrier mobility.