A Low-Temperature, Solution Processable Tin Oxide Electron-Transporting Layer Prepared by the Dual-Fuel Combustion Method for Efficient Perovskite Solar Cells

Although tin oxide (SnO2) has been employed recently as an efficient electron-transporter to realize highly efficient organometal halide perovskite solar cells (PVSCs), it is still quite challenging to apply it through facile solution-based synthesis at low enough temperature (<150 degrees C) to be compatible with the roll-to-roll printing on polymer substrates. In this work, a dual-fuel combustion method has been successfully adapted to modulate the exothermic characteristics and processing temperature (140 degrees C) of SnO2 to achieve homogeneous and crystalline thin film as efficient electron-transporting layer for PVSCs. The fabricated SnO2 film not only has high transparency (from 350 nm to near-infrared region) but also possesses good electron extraction ability, as evidenced by the efficient PL quenching in bilayered SnO2/CH3NH3PbI3 film. By passivating SnO2 surface with a C-60-containing self-assembled monolayer (C-60-SAM), a high power conversion efficiency (PCEmax) of >15% with negligible hysteresis can be achieved in PVSC. This demonstrates the great potential of applying this dual-fuel combustion process to improve processability and charge-transporting properties of metal oxides for organic electronics applications.