Stability improvement of perovskite solar cell using photoswitchable and moisture resistant dual-function interfacial layer

Although the power conversion efficiency of organo-halide perovskite solar cells (PSCs) has reached up to 25.5%, they face challenges to their commercialization due to the lack of stability against moisture, light, and heat. In this work, the durability of the PSC is improved using an efficient interfacial layer that simultaneously protects the perovskite layer against moisture and UV light/heat. The interfacial layer consists of hydrophobic two-dimensional perovskite (2D-PEA2PbI4) and azobenzene phase change material (PCM). The PCM acts as the UV light protector that can efficiently absorb UV light through its isomerization from cis to trans isomer. Remarkably, adding this dual-function interfacial layer prolongs the lifetime of the devices, particularly under one sun illumination and humid atmosphere (65–80% relative humidity). Also, the solid-solid PCM enhances the PCE of devices with 2D-perovskite by the specific orientation of 2D-perovskite between the 3D-perovskite grains. The stability of the modified device has been enhanced almost ten times as compared with the reference device.