Efficient perovskite solar cells with body temperature self-repairing

In recent years,the development of wearable devices has a growing demand for flexible solar cells,Among them,improving the efficiency of the cells,enhancing the stability of device perfor-mance during bending and achieving self-repairing are important focuses of researchers,Perovskite materials have been found to be one of the new materials to improve the efficiency of flexible solar cells[1,2].At present,the problem to be solved is the degra-dation of device performance during bending,which due to defects of perovskite films on flexible substrate and grain boundaries cracks-triggered increased series resistance and carrier leakage[3,4].Some researcher reported the self-repairing of flexible per-ovskite solar cells(PSCs)by introduction of self-healing polymers[5].For example,the flexible PSCs using self-healing polyurethane(s-PU)as a scaffold in the perovskite crystallization process can recover more than 90％of the initial PCE,after 1000 times of 20％tensile cycles[6].However,these self-repairing processes usually require high temperature to achieve,which is very inconvenient for the application as wearable devices.Recently,Song's group[7]from the Institute of Chemistry,Chinese Academy of Sciences reported a new type of self-repairing PSC based on shape memory scaffold polyurethane(SMPU).Adding the SMPU brings three advantages to PSC:(1)the device efficiency is as high as 21.33％;(2)slow down the performance degradation during deformation;(3)the device can real-time self-repair at human body tempera-ture.These advantages provide great convenience and possibility for the application of PSC in wearable field.