Surface Anchoring SnO2 with Fluorinated PCBM for an Efficient and Hysteresis–free N-I-P Configured Perovskite Solar Cells*

One of the key challenges limiting the power conversion efficiency (PCE) of Perovskite solar cells (PSCs) is the mobility and charge separation mechanism between the electron transport layer (ETL) and perovskite [1]. Herein, we studied the effect of using PCBM in the n-i-p configuration PSC. Passivation of SnO2 ETL with fluorinated (FPCBM, F4PCEE) and non-fluorinated PCBM materials demonstrated the recorded improvement of the PCE up to 24.16%. This improvement in performance was mostly due to a significant increase in open circuit voltage (Voc) of 1.143 volts. Incorporating tetra fluorinated PCBM (F4PCEE), a relatively higher fill factor (83.4%) was recorded due to improved quality of the electron layer and hence better charge extraction capacity. For reference devices, the stable (2D PEAI cation incorporated perovskites) and n-i-p configurated PSCs were studied with 22.35% efficiency. Contact angle of the non-contact device layers was improved upto 60% as compared to reference device (45%). Time-resolved photoluminscene used to explore the dynamic properties of interfacial charge and observed the quicker PL quenching for the F4PCC which also exhibits the efficient electron transportation. Overall, high efficiency, reduced hysteresis loss with increased hydrophobicity and photoluminescence quenching of the device layers demonstrate the promising performance of the device in term of electron transportation.

Reference:[1] Shen, Wenjian, et al., Materials Reports: Energy 1.4 (2021): 100060.