Enhanced efficiency and thermal stability of perovskite solar cells using poly(9-vinylcarbazole) modified perovskite/PCBM interface

Poly(9-vinylcarbazole) (PVK) was introduced to modify the interface of perovskite/PCBM. The modified PVK material can induce the formation of the quasi-continuous sheet-shaped perovskite film at the surface of 3D perovskite layer, which may reduce the exposed grain boundaries. Besides, the PVK modified perovskite layer can reduce carrier recombination and accumulation at the interface of perovskite/PCBM and improve the crystallinity of perovskite layer and the interface contact properties. The PVK modification can greatly improve the PCEs and thermal and moisture stability and suppress the J-V hysteresis of perovskite solar cells (PSCs). PSCs with PVK modification achieved champion PCE of 19.03% (average PCE of 18.40%), maintained 80% of the original PCE value aging for 50 days under ambient conduction without encapsulation. Furthermore, PSCs with PVK modification can maintain 87% of the origin PCEs aging for 3 h under 85 °C thermal stress, which are greatly higher than that (26%) of PSCs without PVK modification.