Surface stabilized cubic phase of CsPbI3 and
CsPbBr3 at room temperature
Feng Yang;Cong Wang;Yuhao Pan;Xieyu Zhou;Xianghua Kong;Wei Ji
【期刊名称】《中国物理：英文版》 【年(卷),期】2019(028)005
【摘要】Inorganic halide perovskites CsPbX3 (X=I, Br) have attracted tremendous attention in solar cell applications. How-ever, the bulk form of the cubic phase CsPbX3, which offers moderate direct bandgaps, is metastable at room temperature and tends to transform into a tetragonal or orthorhombic phase. Here, our density functional theory calculation results found that the surface energies of the cubic phase are smaller than those of the orthorhombic phase, although the bulk counterpart of the cubic phase is less stable than that of the orthorhombic phase. These results suggest a surface stabilization strategy to maintain the stability of the cubic phase at room temperature that an enlarged portion of surfaces shall change the relative stability of the two phases in nanostructured CsPbX3. This strategy, which may potentially solve the long-standing stability issue of cubic CsPbX3, was demonstrated to be feasible by our calculations in zero-, one-, and two-dimensional nanos-tructures. In particular, confined sizes from few to tens of nanometers could keep the cubic phase as the most thermally favored form at room temperature. Our
Surface stabilized cubic phase of CsPbI3 and CsPbBr3 at room temperature
