https://www.selleckchem.com/products/syrosingopine-su-3118.html Inorganic cesium lead halide (CsPbI3) is a promising candidate for next-generation photovoltaic devices, but photoactive α-phase CsPbI3 can rapidly transform to non-photoactive yellow δ-CsPbI3 in a humid atmosphere. Here, we report that partial substitution of cesium by the potassium or rubidium element can effectively improve the phase stability against moisture by forming a water-repelling surface layer with Rb/K segregation. Using density functional theory, we found that the water-induced polarization, which triggers the PbI62- octahedron distortion and accelerates the phase transition, can be effectively alleviated by incorporating Rb/K elements. Further exploration of transition states suggests that Rb/K doped surface layers result in a higher activation barrier for water penetration. The electronic structure analysis further reveals that the barrier enhancement originates from the absence of the participation of inner 5p electrons in Rb/K-H2O binding, which induces a much lower energy barrier in pristine CsPbI3. Based on these improvements, the doped perovskites remained in the major α-phase after direct exposure to ambient air (RH ∼ 30%) for 5 hours, while pristine CsPbI3 showed an irreversible degradation. With the clarified mechanism of enhanced phase stability of Rb/K incorporation, we suggest such a doping method as a promising strategy to be widely applied in the field of photovoltaic devices.Because of their excellent capacity to significantly improve the bioavailability and solubility of chemotherapy drugs, block copolymer micelles are widely utilized for chemotherapy drug delivery. In order to further improve the anti-tumor ability and reduce unwanted side effects of drugs, tumor-targeting peptides were used to functionalize the surface of polymer micelles so that the micelles can target tumor tissues. Herein, we synthesized a kind of PEG-PLA that is maleimide-terminated and then conjugat