Enhanced efficiency and stability of perovskite solar cells achieved by incorporating potassium cation-18-crown ether-6 complexes

A facilitated approach for improving the efficiency and stability of perovskite solar cells is explored by introducing the potassium cation-18-crown ether-6 (18C6) complexes at the interface of the electron transport layer and perovskite absorber layer. The results indicated that the 18C6 molecular can capture the potassium cation (K+) owing to the matched size of the K+ and crown ether cavity, which eventually suppresses the migration of K+ and then improving the stability of perovskite solar cells while retaining its excellent passivation effect. Furthermore, 18C6 also plays a crucial role in trap density reduction by mitigating the grain boundaries, passivating the uncoordinated Pb2+in the crystals, as witnessed by the SEM images, absorption spectra, carrier lifetime, and chemical bonding information. Ultimately, the short circuit current, open circuit voltage, fill factor, and conversion efficiency are enhanced accompanied with the improved long-term stability and eliminated hysteresis. The champion efficiency of 21.57% is delivered for the 18C6–K+ incorporated solar cells, much-leading the control cell without the 18C6–K+ incorporation with an efficiency of 20.25%.