| 초록 |
This is the first report on ternary diagram of phase, optical bandgap, and photoluminescence intensity of CsPbX3 perovskite with three vertices of CsPbI3, CsPbBr3, CsPbCl3. To obtain the exact designed composition, all the compositions were synthesized using mechanochemical reaction. At room temperature CsPbI3 have stable δ phase (non-perovskite, orthorhombic) , and it attains metastable γ phase (orthorhombic) on heat treatment above ~350℃. Phase maps for each composition were separately derived before and after heat treatment. In the ternary phase maps, single or multi-phase regions were assigned to each composition. For single γ phase, c-axis lattice constant linearly decreased with the decrease in average radius of X-site ions. In contrast, decrease in the radius of X-site, linearly increased the bandgap from 1.73 to 2.96 eV. The ternary diagram’s estimated lattice constants and bandgap values obeyed Vegard’s law with negligible deviation. Hence, the bandgap and lattice constant for a certain CsPbX3 composition with varied ratios of X-site (X: Cl, Br, and I), can be easily defined using the CsPbX3 ternary diagram. Furthermore, photoluminescence intensity maps show desirable compositions for red, green, and blue-light emission. These ternary maps are important and useful for designing of a target perovskite composition for various optoelectronic applications.
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