Plasma damage control via adjusting the target to substrate distance used to prepare semi-transparent perovskite solar cells

To realize semi-transparent perovskite solar cells (ST-PSCs), a high-quality amorphous transparent cathode must be deposited on the perovskite active layer without plasma damage at room temperature. In this study, we have investigated the effect of the target-to-substrate distance (TSD) on the performance of ST-PSCs during linear facing target sputtering (LFTS) to achieve the plasma damage-free sputtering of Ga and Ti co-doped In2O3 (IGTO) upper cathodes on planar ST-PSCs. We comprehensively compare the electrical, optical, structural, and morphological properties of IGTO cathodes grown using different TSDs and correlate them to performances of the ST-PSCs to determine the optimal TSD. We demonstrate the importance of optimal TSD and deposition mechanism at different TSDs based on the properties of the resulting IGTO films and ST-PSC performance. At an optimal TSD of 6 cm, the amorphous IGTO film demonstrate a sheet resistance of 9.22 Ω/sq. and optical transmittance of 87.74%. The ST-PSC constructed using the optimized IGTO upper cathode exhibit an open-circuit voltage of 1.12 V, short circuit current of 20.23 mA/cm2, fill factor of 83.73%, power conversion efficiency of 18.91%, and average transmittance of 19.31%. Consequently, the choice of the TSD is crucial in LFTS process for the fabrication of high-performance ST-PSCs without plasma damage.