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

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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 PO43− ion in dibasic sodium phosphate (Na2HPO4, DSP). The PO43− 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 PO43− inhibits horizontal growth of (Sb4S(e)6)n ribbons due to size effects, thus achieving desirable [hk1] orientation. Moreover, the introduction PO43− 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%.