Dataset of "An Alternative Chlorine-Assisted Optimization of CdS/Sb2Se3 Solar Cells: Towards a Unified Understanding Mechanism"

The current strategies in the development of Sb2Se3 thin film solar cells involvefabrication and optimization of superstrate and substrate device architectures, with thepreferable choice for TiO2 and CdS heterojunction layers. For CdS-based superstratecells, several studies reported the necessity to apply CdCl2 or other metal halidebasedpost-deposition treatment (PDT), highlighting improvement of CdS/Sb2Se3device efficiency. However, the need, effect, and mechanism of such PDT are veryoften not described. Additionally, the fact that many groups have not succeeded indemonstrating its benefits suggests that this strategy is not straightforward, requiring adeeper understanding towards a more unified concept. The present study proposes analternative approach to the challenging CdCl2 PDT of CdS in CdS/Sb2Se3 device,involving controllable Cl incorporation in CdS films by systematically varying theconcentration of NH4Cl in the CBD precursor solution from 1 to 8 mM. Structural andelectrical characterizations are correlated with advanced measurements of ScanningKelvin Probe, surface photovoltage, and atomic force microscopy to understand theimpact of Cl incorporation on the properties of CdS films and CdS/Sb2Se3 devices.The validity of Cl incorporation in the CdS lattice and interdiffusion processes at theCdS-Sb2Se3 interface is confirmed by secondary ion mass spectrometry analysis. It isdemonstrated that incorporation of 1 mM of NH4Cl, as a Cl source in CBD CdS, canboost the PCE of CdS/Sb2Se3 by ~20%. With this approach, we offer newperspectives on the optimization methodology for Cl-based CdS/Sb2Se3 deviceprocessing and complementary understanding of the physiochemistry behind theseprocesses.