Stable and efficient full-printable solar cells using inorganic metal oxide framework and inorganic perovskites

Abstract Inorganic perovskites such as CsPbI2Br have attracted much attention owing to their intrinsic merits of thermal stability. However, the phase instability of CsPbI2Br in real‐world operating conditions remains a major impediment to its prospective applications. Herein we report a method on enhancing the phase stabilization of inorganic perovskite CsPbI2Br and device performance in corresponding device engaged by Mg2+ ion substitution. Owing to small ionic radius and superior electron donating ability of Mg2+, a well-match in crystalline lattices between Cs+ and cubooctahedral void of Mg-substituted perovskite compounds and the reduced interaction between water molecules and perovskite all can offer stable perovskite phase of CsPbxMg1−xI2Br in ambient atmosphere. Moreover, we observed the enlarged charge diffusion lengths and more faster charge transportation rate for Mg-substituted perovskite-based device. Consequently, the resultant perovskite solar cell using CsPbxMg1−xI2Br with a full printable framework of FTO/c‐TiO2/m‐TiO2/Al2O3/NiO/carbon achieves a power conversion efficiency of 10.8%. We further noticed that a common phenomenon of energy loss in mesoporous perovskite solar cells can be significantly reduced in the case of CsPb0.98Mg0.02I2Br.