All Room-Temperature-Processed Carbon-Based Flexible Perovskite Solar Cells with TiO2 Electron Collection Layer

Herein, low-cost, solution-based, all room-temperature-processed carbon-based triple-cation perovskite solar cells (C-PSC) with TiO2 electron transport layer (ETL) are reported. The hydrothermally synthesized anatase TiO2 nanoparticles with titanium diisopropoxide bis(acetylacetonate) doping results in high-quality and uniform ETL with improved interparticle connectivity. The room-temperature crystallization of pure photoactive alpha-phase perovskite absorber layer MA(0.14)FA(0.77)Cs(0.09)PbI(2.5)Br(0.5) is achieved with the combination of diethyl ether anti-solvent treatment and nitrogen gas-assisted drying. The resultant film is dense and smooth with pinhole-free uniform grain distribution. The C-PSCs with TiO2 processed at 500 degrees C give 12.07% efficiency, whereas the room-temperature-processed TiO2 (RT TiO2) ETL-based device shows 10.57% efficiency. Furthermore, this RT TiO2 and room-temperature crystallized perovskite layer are employed in all room-temperature-processed flexible C-PSC with approximate to 8% efficiency. The fabricated C-PSCs exhibit significant stability for more than 1 month, with a T-80 of 335 h.

Automated summary

In this study, low-cost, solution-based, all room-temperature-processed carbon-based triple-cation perovskite solar cells with TiO2 electron transport layer (ETL) were reported. The combination of improved interparticle connectivity of TiO2 ETL and room-temperature crystallization method led to high-efficiency and stable solar cells.