Performance enhancement of Sb2(S,Se)3 solar cells through neodymium ion flow doping

Doping the light absorber layer of antimony chalcogenides with extrinsic ions is an effective approach for improving their photovoltaic quality. These dopant ions generally reside at positions other than the crystal lattice or form an alloy (e.g., AgSb(S,Se)3) with a poor device performance. Therefore, incorporating such ions into an antimony chalcogenide lattice such that there is a positive influence on device quality would be highly useful. Herein, doping of Nd3+ for Sb2(S,Se)3 is carried out via a modified hydrothermal deposition process. Notably, these ions are incorporated into the crystal lattice and migrate to the CdS/Sb2(S,Se)3 interface after doping, which are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. Nd3+ doping produces benign effects on the crystal orientation, film morphology, optoelectronic properties, and defect passivation of the Sb2(S,Se)3 films. Consequently, all the photoelectrical parameters of Sb2(S,Se)3 solar cells doped with Nd3+ are enhanced, delivering a remarkable efficiency of 8.24 %. Furthermore, the best device stored in air only shows a slight decrease in efficiency in the 2400-h aging test. Overall, this study provides an effective doping strategy to improve the photovoltaic quality of Sb2(S,Se)3 films.