Bilayered graded phase homojunction FA0.15MA0.85PbI3-based organic-inorganic hybrid perovskite solar cells crossing 22 % efficiency

Making highly efficient and stable perovskite solar cells (PSCs) are often based on the processing techniques, band gap of the material and effective interface charge separation. The efficiency of PSCs can be enhanced through several methods including the utilization of a solar-friendly absorber, interface passivation and the implementation of multi-junction spectrally matched absorbers or bilayered phase homojunction (BPHJ) consisting of identical absorbers. Here, we demonstrated BPHJ concept by stacking identical compositions of highly efficient and stable FA0.15MA0.85PbI3 perovskite absorbers adopting solution process (SP) and thermal evaporation (TEV) techniques. We successfully achieved FA0.15MA0.85PbI3 (SP)/FA0.15MA0.85PbI3-(TEV) based BPHJ normal n-i-p devices, which significantly crossing 22. % PCE. These improvement stems from effective deposition method for achieving high-quality FA0.15MA0.85PbI3-based BPHJ enabling smooth charge transfer at the interfaces. The resulting BPHJ-based champion device achieve a 22.13 % PCE and retain >95 % its original efficiency over 1000 hours.