Abstract
Perovskite solar cells (PSCs) have been developed significantly in recent years, the latest record power conversion efficiency (PCE) of PSCs has surged to 25.7% in 2022 from 3.8% in 2009. However, the poor operating stability has become the main obstacles for commercialization. In order to obtain both high efficiency and good stability at the same time, we did a series of jobs as followed.
Firstly, we selected the inverted p-i-n perovskite solar cell as baseline devices, with architecture of ITO/NiOx/CsFAMAPbI3-xBrx/PCBM/BCP/Ag and optimized each layer by adjusting the spin speeds, surface treatments (UVO zone or oxygen plasma), concentrations as well as annealing temperature of NiOx, perovskite, PCBM and BCP. The optimized control device obtained an PCE over 18%.
Then, we firstly modified the perovskite/ETL interface with PEAI to form 2D/3D structure perovskites and observed that PCE will increase after exposing the device in ambient for certain period of time. In order to unleash the potential performance, exposure in various humidity for different time periods were conducted and obtained a 20.24% PCE at optimal conditions.
Then, we introduced 2PACz as the interfacial passivator and achieved a champion PCE of 22.45% after moisture exposure treatment. Comprehensive characterizations were conducted to investigate the moisture treatment effect.
Thereafter, the hole transport layer was transferred from NiOx to 2PACz SAM for its improved PCE and stability. And four interface modifiers (PEAI, 4-FPEAI, PEABF4, FABF4) were selected into the pero/PCBM interface and investigated the modification effect in PSC devices. After modification, the operating stability were improved for all cases, while PCE fluctuates, this phenomenon was investigated with a series of characterizations.
Keywords: Perovskite solar cells, interface engineering, SAM, PEAI, 3D/2D.
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