Synergistic effect of manganese stearate encapsulating CsPbI3 perovskite quantum dots with high phase stability

Inorganic cesium lead halide perovskite quantum dots (CsPbX3 PQDs, X = Cl, Br or I) have drawn great attention because of their superb optoelectronic properties. However, the phase transition from cubic to orthorhombic accelerates the degradation of CsPbI3 PQDs, resulting in poor stability. Here, we proposed a facile method to encapsulate CsPbI3 PQDs in manganese stearate (MnSt2, C36H70MnO4) powder, in which Mn2+ is introduced into CsPbI3 crystal to increase the tolerance factor, leading to suppress phase transition. The presence of MnSt2 not only serves as a hydrophobic matrix to protect CsPbI3 PQDs from the surrounding environment but also passivates the surface of PQDs. Benefiting from the synergistic effect of MnSt2, the as-synthesized CsPbI3-MnSt2 nanocomposites exhibit enhanced phase stability in ambient conditions for more than 180 days. Furthermore, a white light-emitting diode (WLED) with excellent performance was constructed, demonstrating that encapsulation of PQDs with MnSt2 represents a valid strategy to stabilize CsPbI3 PQDs toward optoelectronic application.