Enhanced comprehensive performance of carbon-based hole-transport-layer-free CsPbI2Br solar cells by a low-cost and stable long chain polymer†
Abstract
Hole-transport-layer (HTL)-free CsPbI2Br solar cells based on a carbon electrode have attracted widespread interest because they have a simple device configuration and good light and thermal stability, and moreover are independent of high-cost HTLs and precious metal electrodes. However, the device performance including the power conversion efficiency (PCE) and operation stability is limited by the poor crystallinity of CsPbI2Br, the mismatched energy levels and poor contact between the carbon electrode and the perovskite layer. Herein, a simple but effective additive strategy is reported to efficiently improve the crystallinity and reduce the surface roughness of the CsPbI2Br layer, thus remarkably boosting the PCE and meanwhile enhancing the working stability by adding a low-cost and stable long chain polymer, i.e., acrylonitrile butadiene styrene (ABS) into CsPbI2Br. The corresponding device delivers a boosted PCE of 14.27% from 11.80% for the control device without ABS addition.