Perovskite surface management by thiol and amine copper porphyrin for stable and clean solar cells

Abstract

The leakage of noxious lead and the instability of perovskite film induced by interfacial defects have impeded the practical application of perovskite solar cells (PSCs). Here, we develop a perovskite surface management strategy by the post-treatment with a copper porphyrin containing thiol and secondary amine group (Cu-Por). The thiol-terminal in Cu-Por can coordinate with the Pb defects on the perovskite surface. The central Cu2+ ions in Cu-Por tune the electron distribution within porphyrin ring, thereby effectively binding the I− and I2 on the perovskite surface by π-I interaction and the hydrogen-bonds between the side chain N–H group with I− and I2. Finally, the Cu-Por-treated PSCs gave the best efficiency of 21.24%. More importantly, the modified device maintained over 90% of its initial efficiency under AM 1.5G illumination or heated at 85 °C in N2 atmosphere after 2000 h. Especially, the Cu-Por treated PSCs can prevent the leakage of lead. This finding provides a new perovskite surface management strategy to fabricate the stable and clean PSCs.