Low-Temperature Processed TiO_x/Zn_1−xCd_xS Nanocomposite for Efficient MAPbI_xCl_1−x Perovskite and PCDTBT:PC₇₀BM Polymer Solar Cells

Abstract

The majority of high-performance perovskite and polymer solar cells consist of a TiO2 electron transport layer (ETL) processed at a high temperature (>450 °C). Here, we demonstrate that low-temperature (80 °C) ETL thin film of TiOx:Zn1−xCdxS can be used as an effective ETL and its band energy can be tuned by varying the TiOx:Zn1−xCdxS ratio. At the optimal ratio of 50:50 (vol%), the MAPbIxCl1−x perovskite and PCBTBT:PC70BM 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.

Keywords

• electron transport layer
• TiO_x
• ZnCdS
• solar cells
• perovskite
• polymer
• scanning Kelvin probe microscopy