Effect of B-site doping on the phase and thermal stability of CsPbI3 perovskite

B-site doping has been regarded as an effective strategy to stabilize the desired perovskite phase of CsPbI3. However, on the basis of first-principles study, we demonstrate that only Sn2+ doping could enhance both the phase and thermal stability of CsPbI3 perovskite while doping with other cations such as Mn2+, Zn2+, Sr2+, Ca2+, Mg2+, Bi3+ and Sb3+ either decreases the phase or thermal stability of CsPbI3 host or has little influence. The experimentally observed improvement of stability should be ascribed to nanocrystallization or the use of dimethylformamide (DMF) solvent rather than B-site doping.