Tuning anchoring groups of “Y-Type” self-assembled hole transport materials for interface passivation in inverted perovskite solar cells

Self-assembled molecules (SAM) as hole transport materials play an important role in performance of inverted perovskite solar cells (PSCs). Common anchoring groups like 2-cyanoacrylic acid and phosphonic acid provide strong anchoring at the bottom interface and excellent passivation during inverted PSC fabrication. In this study, two Y-type hole transport materials (HTMs), MPA-TB-CA and MPA-TB-CPA, are designed. They have the advantages of good interfacial effects after introducing different anchoring groups into the D-A structure, simple synthesis process and low cost. Therefore, the organic transition between ITO and perovskite layer was established, the frontier molecular orbital energy level was modulated, and the transmittance based on ITO reached 97.1 %. Finally, we find that the inverted PSCs with MPA-TB-CA HTM have an excellent power conversion efficiency (PCE) of 19.18 % and negligible hysteresis. In addition, it has a strong binding force with Pb²⁺ ions, and the passivated burial interface shows good performance. We believe this design strategy will provide new insights into the commercialization of efficient HTM for PSCs with environmental and outstanding performance advantages.