Design of imidazole diiodate pretreatment for interfacial modification in perovskite solar cells

Suboptimal interfacial stabilities and mismatched energies between the electron transport layer (ETL) and perovskites have limited the performance and stability of perovskite solar cells. Herein, we synthesize 1-(3-aminopropyl)-imidazole diiodate (AIDI) and employ it as a pretreatment additive at the indium tin oxide (ITO)/SnO2 interface. This approach facilitates a bottom-up infiltration process, enabling modification of the ITO/SnO2, SnO2 ETL, and SnO2/perovskite interfaces. The AIDI pretreatment serves a multifaceted role: it enhances the mobility of the SnO2 ETL, passivates defects at the surface of SnO2, and facilitates ultrafast electron extraction at the interfaces, thereby improving carrier transport and fortifying resistance against oxygen-induced photodegradation. Consequently, devices incorporating the AIDI/SnO2 ETL configuration demonstrate an efficiency of 24.17%. This outcome not only showcases the potential of AIDI as a transformative additive but also provides a trajectory for further refining the buried interface to enhance the overall performance of perovskite solar cells.