PO43− Tetrahedron Assisted Chelate Engineering for 10.67%‐Efficient Antimony Selenosulfide Solar Cells

Anisotropic carrier transport and deep-level defect of antimony selenosulfide (Sb2(S,Se)3) absorber are two vital auses restraining the photovoltaic performance of this emerging thin-film solar cell. Herein, chelate engineering is proposed to prepare high-quality Sb2(S,Se)3 film based on hydrothermal deposition approach, which realizes desirable carrier transport and passivated defects by using tetrahedral PO4 3- ion in dibasic sodium phosphate (Na2HPO4, DSP). The PO4 3- Lewis structure, on one hand in the form of [(SbO)3(PO4)] chelate, can adsorb on the polar planes of cadmium sulfide (CdS) layer, promoting the heterogeneous nucleation, and on the other hand, the tetrahedral PO4 3- inhibits horizontal growth of (Sb4S(e)6)n ribbons due to size effects, thus achieving desirable [hk1] orientation. Moreover, the introduction PO4 3- effectively passivates the antisite defect SbS1. These synergistic effects have effectively improved carrier transport and reduced non-radiative recombination of the Sb2(S,Se)3 absorber. Consequently, the DSP-modified Sb2(S,Se)3 device efficiency increases from 8.59% to 10.67%.