SrCl₂ Derived Perovskite Facilitating a High Efficiency of 16% in Hole‐Conductor‐Free Fully Printable Mesoscopic Perovskite Solar Cells

Despite the breakthrough of over 22% power conversion efficiency demonstrated in organic–inorganic hybrid perovskite solar cells (PVSCs), critical concerns pertaining to the instability and toxicity still remain that may potentially hinder their commercialization. In this study, a new chemical approach using environmentally friendly strontium chloride (SrCl 2 ) as a precursor for perovskite preparation is demonstrated to result in enhanced device performance and stability of the derived hole‐conductor‐free printable mesoscopic PVSCs. The CH 3 NH 3 PbI 3 perovskite is chemically modified by introducing SrCl 2 in the precursor solution. The results from structural, elemental, and morphological analyses show that the incorporation of SrCl 2 affords the formation of CH 3 NH 3 PbI 3 (SrCl 2 ) x perovskites endowed with lower defect concentration and better pore filling in the derived mesoscopic PVSCs. The optimized compositional CH 3 NH 3 PbI 3 (SrCl 2 ) 0.1 perovskite can substantially enhance the photovoltaic performance of the derived hole‐conductor‐free device to 15.9%, outperforming the value (13.0%) of the pristine CH 3 NH 3 PbI 3 device. More importantly, the stability of the device in ambient air under illumination is also improved.