Low-Temperature Processed TiO/ZnCdS Nanocomposite for Efficient MAPbICl Perovskite and PCDTBT:PCBM Polymer Solar Cells.

The majority of high-performance perovskite and polymer solar cells consist of a TiO electron transport layer (ETL) processed at a high temperature (>450 °C). Here, we demonstrate that low-temperature (80 °C) ETL thin film of TiO:ZnCdS can be used as an effective ETL and its band energy can be tuned by varying the TiO:ZnCdS ratio. At the optimal ratio of 50:50 (vol%), the MAPbICl perovskite and PCBTBT:PCBM polymer solar cells achieved 9.79% and 4.95%, respectively. Morphological and optoelectronic analyses showed that tailoring band edges and homogeneous distribution of the local surface charges could improve the solar cells efficiency by more than 2%. We proposed a plausible mechanism to rationalize the variation in morphology and band energy of the ETL.