Improving the performance and reproducibility of inverted planar perovskite solar cells by using tetraethyl orthosilicate as the anti-solvent.

Anti-solvent assisted crystallization has been extensively used for perovskite solar cells (PSCs). Whereas, this approach has a fatal drawback -- low reproducibility, originating from the extremely harsh operating conditions of the current anti-solvents. As a result, only skilled technicians are qualified to be scheduled to prepare perovskite thin films in order to fabricate high-efficiency devices, which lowers the pace of progress of PSCs. Besides, the most popular anti-solvents of toluene (TL) and chlorobenzene (CB) are highly toxic and carcinogenic. On account of these, we tried to develop a low hazardous anti-solvent that enable achieving high-efficiency and highly reproducible PSCs. Herein, tetraethyl orthosilicate (TEOS) was employed in the inverted NiOX-based planar PSC for engineering efficient perovskite layer, achieving a power conversion efficiency of 17.02% on glass substrates and 14.49% on flexible polymer substrates with negligible hysteresis, which was even outperforming TL and CB. More importantly, TEOS PSCs exhibited much higher reproducibility than their counterparts. These desirable features should be ascribed to the higher-quality perovskite films with larger grain size, reduced density of defects and thus smoother carrier transportation and slower carrier recombination. This work drives PSCs another step toward industrial scale commercialization and also pave the way for environmental rollable photovoltaic applications.