Evaluating the Film Orientation and Grain Boundary of Vacuum- and Solution-Processed Sb<sub>2</sub>S<sub>3</sub> Films toward Efficient Solar Cells
Zihao Chen, Xiao Chen, Jiacheng Zhou, Bo Tang, Yuan Li, Xi Yang, Ru Zhou
Abstract
The quasi-one-dimensional environment-friendly light-harvesting material Sb 2 S 3 attracts tremendous attention for photovoltaic applications due to its superior materials and optoelectronic properties. The film orientation and grain boundary are two crucial concerns that greatly influence the device performance of Sb 2 S 3 solar cells. In this work, the film orientation and grain boundary of Sb 2 S 3 thin films processed by vacuum-based close-spaced sublimation (CSS) and solution-based chemical bath deposition (CBD) and hydrothermal deposition (HD) methods were evaluated. Careful characterization reveals that the vacuum-based method typically affords compact Sb 2 S 3 films with pronounced [ hk 1] orientations, while solution-based methods deliver large-grained Sb 2 S 3 films with ultralow grain boundary density. The CBD- and HD-processed devices yielded power conversion efficiencies of 6.43 and 6.51%, respectively, higher than 5.81% for the CSS-processed device. This should be closely associated with the balance of the favorable [ hk 1] orientations for efficient charge transport and the reduced grain boundary density for suppressed carrier recombination. This work provides insight information for further enhancing the performance of Sb 2 S 3 solar cells by devoting more attention to the film orientation and grain boundary.