Efficient and Stable Inverted Perovskite Solar Cells Using Donor–Acceptor–Donor Small Molecules to Tuning NiO_x/Perovskite Interfacial Microstructure

Nickel oxide (NiO x ) is one of the most widely used inorganic hole transport materials for inverted perovskite solar cells (PSCs), which has the advantages of low cost, easy preparation, and good stability. However, the energy‐level mismatch and interfacial redox reactions at the NiO x /perovskite interface limit the performance of NiO x ‐based PSCs. Herein, triphenylamine‐2,1,3‐benzothiadiazole‐triphenylamine (TBT) small‐molecule material is first used as an interfacial modification layer between NiO x and perovskite. The deposition of TBT on NiO x helps to hinder the contact between NiO x and perovskite, improves the electrical conductivity, passivates interfacial defects, and inhibits the recombination of interfacial carriers. TBT makes the valance band top energy level of NiO x better match that of perovskite and promotes the hole transfer at NiO x /perovskite interface, and the hole transfer rate increases from 2.19 × 10 10 to 4.12 × 10 10 s −1 . The TBT‐based device obtains a champion power conversion efficiency (PCE) of 21.84%, much higher than the control device (18.62%). Furthermore, the optimized device which is conserved in 30 ± 5% relative humidity and 25 °C environments more than 1000 h retains 90% of the initial efficiency. A effective strategy to improve the PCE and stability of NiO x ‐based PSCs is provided.