Self-Assembly of Hybrid Oxidant POM@Cu-BTC for Enhanced Efficiency and Long-Term Stability of Perovskite Solar Cells

Abstract

The controllable oxidation of spiro-OMeTAD and improving the stability of hole-transport materials (HTMs) layer are crucial for good performance and stability of perovskite solar cells (PSCs). Herein, we report an efficient hybrid polyoxometalate@metal-organic framework (POM@MOF) material, [Cu₂ (BTC)_4/3 (H₂ O)₂ ]₆ [H₃ PMo₁₂ O₄₀ ]₂ or POM@Cu-BTC, for the oxidation of spiro-OMeTAD with Li-TFSI and TBP. When POM@Cu-BTC is introduced to the HTM layer as a dopant, the PSCs achieve a superior fill factor of 0.80 and enhanced power conversion efficiency 21.44 %, as well as improved long-term stability in an ambient atmosphere without encapsulation. The enhanced performance is attributed to the oxidation activity of POM anions and solid-state nanoparticles. Therefore, this research presents a facile way by using hybrid porous materials to accelerate oxidation of spiro-OMeTAD, further improving the efficiency and stability of PSCs.

Keywords: hole-transport materials; metal-organic frameworks (MOFs); perovskites; polyoxometalates; solar cells.