Room Temperature Processed Transparent Amorphous InGaTiO Cathodes for Semi-Transparent Perovskite Solar Cells

In order to ensure high-performance semitransparent perovskite solar cells (ST-PSCs), the deposition of high-quality scalable transparent cathodes on ST-PSCs at room temperature is necessary. In this study, we designed an amorphous InGaTiO (IGTO) electrode, prepared by linear facing target sputtering (LFTS) as a transparent cathode for ST-PSCs. Even in the room temperature sputtering process, the amorphous IGTO cathode showed a low sheet resistance of 9.895 Ohm/square and a high optical transmittance of 87.53% without the occurrence of in situ or postannealing, unlike Sn-doped In₂O₃ (ITO) electrodes. Due to its complete amorphous structure and low energy sputtering, the amorphous IGTO electrode showed superior mechanical properties, when compared to other typical crystalline ITO films. Additionally, the LFTS process led to a low energy deposition of the amorphous IGTO cathode on ST-PSCs, and did not result in plasma damage on perovskite active layers, which is often typical in conventional situations of direct current sputtering. On the basis of these optimized plasma damage-free sputtering conditions, we examined the feasibility of LFTS-grown IGTO cathodes for ST-PSCs. In our results, we observed that a similar performance of the ST-PSC with an IGTO cathode with the opaque PSC with Ag cathode, indicated that amorphous IGTO cathode is a prospective transparent cathode for ST-PSCs on both rigid or flexible substrates.