High efficiency and stability of perovskite solar cells using MD-697 doped poly (9-vinyl carbazole) modified interface of PCBM/perovskite layers

Using interface modification is an effective method to improve the crystallinity and stability of perovskite solar cells (PSCs). P-type poly(9-vinylcarbazole) (PVK) inserted the interface of perovskite and electron transport layer (ETL), which can improve the crystallinity and stability of PSCs. However, pure PVK-modified interface of perovskite/ETL is sensitive to the modified thickness and UV exposure, which can only improve limited PCE and anti-UV durability compared to the reference PSCs. The anti-oxidant (1,2-dioxoethylene)bis(iminoethylene) bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (MD-697) doped into poly (9-vinyl carbazole) (PVK) was firstly introduced to modify the interface of perovskite and phenyl-C-61-butyric acid methyl (PCBM). MD-697:PVK-modified PSCs got the champion PCEs of 20.75% with less hysteresis effect, which is far higher than PCE (19.03%) of PVK-modified PSCs, (17.58%) MD-687-modified PSCs and (17.1%) of reference PSCs. MD-697:PVK-modified PSCs remained 89% of the original PCEs aged for 2800 h at room temperature and RH 85% under encapsulating condition and still remained 94% of the original PCE value aged for 6 h UV irradiation, which show best moisture resistance and UV durability. The joint coordination of C=O, NH and OH groups of MD-697 and carbazole groups of PVK can contribute to best crystallization of the perovskite layer, improving passivation effect and superior interface contact at perovskite/PCBM layers. The quasi-continuous two-dimension layer was formed on the surface of 3D perovskite film, which can further inhibit moisture invasion along grain boundaries. Therefore, MD-697:PVK jointly modified the perovskite film is an effective method to obtain efficient and stable PSCs.

Automated summary

Using interface modification is an effective method to improve the crystallinity and stability of perovskite solar cells. P-type poly(9-vinylcarbazole) (PVK) inserted at the interface of perovskite and electron transport layer (ETL) can enhance the crystallinity and stability of the cells. However, pure PVK modification is sensitive to thickness and UV exposure, resulting in limited improvement compared to reference cells.