Degradation induced Lattice Anchoring Self-passivation in CsPbI3-xBrx
Research output: Contribution to journal › Article › peer-review
Colleges, School and Institutes
The all-inorganic halide perovskite (CsPbI3) holds promise for photovoltaic applications but suffers from a detrimental phase transformation to a non-perovskite phase δ-CsPbI3 at low-temperature. Of the different perovskite polymorphs, there has been a wide range of studies on γ-CsPbI3 due to its kinetic stability at near room-temperature. However, synthesis routes to this and other all-inorganic halide perovskite are still not ideal, requiring uneconomic elimination of humidity as well as quenching from elevated temperature. Water/moisture is commonly meticulously avoided due the fact that it can accelerate the detrimental degradation of the perovskite. In our synthesis, we took an alternative approach of engineering an in situ degradation process to form an dual-functional PbI(OH) protective coverage, and succeeded in performing the first room-temperature synthesis of γ-CsPbI3 in ambient humidity. The vastly improved stability benefits from both lattice anchoring and physical coverage of γ-CsPbI3 by an ultra-thin PbI(OH) layer. The resultant γ-CsPbI3 is stable for more than 2 months at ambient conditions (25 oC, RH = 30%-60%) and more than 12 hours at 175 oC in air without any degradation. Furthermore, we show that this novel facile method can be successfully applied to mixed halide perovskites such as CsPbI2Br, and this has allowed the first experimental synthesis of the γ-polymorph of CsPbI2Br. Thus, our work provides an efficient degradation-induced lattice-anchoring self-stabilization strategy, and a new avenue to the economic synthesis of all-inorganic perovskite materials at room-temperature under ambient conditions.
|Journal||Journal of Materials Chemistry A|
|Early online date||30 Apr 2020|
|Publication status||Published - 21 May 2020|