| 초록 |
We study the parameters that can influence the electron extraction in planar perovskite solar cells (P-PSCs) using spin-coated SnO2 and TiO2, anodized-TiO2, and bilayered electron transport layers (ETL) composed of SnO2 and TiO2 or SnO2 on a-TiO2 (SnO2@a-TiO2). These varied free energy difference (∆G) values between the ETL and perovskites, electron mobility (μe) of the ETL, and quality of physical contact between the ETL and fluorine-doped tin oxide (FTO). The bilayered ETL (SnO2@a-TiO2) gives a large ∆G as well as defect-free physical contact. The resulting P-PSC exhibits a PCE of 21.1% and stabilized efficiency of 20.2% with reduced hysteresis. This result emphasizes that a large free energy difference (∆G) value plays an important role in electron extraction. More importantly, the defect-free physical contact is also crucial for achieving improved electron extraction. |
