Terbium chloride post-treatment for highly efficient and stable Sb2(S,Se)3 solar cells

An anion-cation synergistic strategy is adopted by TbCl 3 post-treatment in Sb 2 (S,Se) 3 solar cells. • This strategy induces the further growth of Sb 2 (S,Se) 3 with favorable crystal orientation. • TbCl 3 -treatment suppresses deep-level defects and adjusts band alignment of Sb 2 (S,Se) 3 films. • The champion device achieves a PCE of 10.11% with excellent stability. Antimony selenosulfide (Sb 2 (S,Se) 3 ) is a promising quasi-one-dimensional photovoltaic material in the application of solar cell field because of its outstanding optoelectronic properties. It is extremely difficult to achieve the Shockley-Queisser limit due to the presence of various defects and the less favorable (hk0) crystal orientation in Sb 2 (S,Se) 3 films. Here, we report an anion-cation synergistic strategy to enhance the quality of Sb 2 (S,Se) 3 films by terbium chloride post-treated process. Both Tb 3+ and Cl − ions are incorporated into the crystal lattice of Sb 2 (S,Se) 3 after post-treatment, which is confirmed by X-ray photoelectron spectroscopy and X-ray diffraction. This anion-cation synergistic effect promotes the Sb 2 (S,Se) 3 films to have a preferred (hk1) crystal orientation, larger grain size, suppressed deep-level defects and more favorable energy band alignment to facilitate charge carrier transport. Consequently, terbium chloride post-treatment enhances the performance of Sb 2 (S,Se) 3 solar cells, achieving a remarkable of 10.11%. Furthermore, the champion devices exhibit an excellent storage, humidity and thermal stability over 800 h aging test. This work provides a valuable strategy for fabricating high-quality of Sb 2 (S,Se) 3 films and high-efficiency inorganic horizontal and vertical PN heterostructure solar cells.