First principle investigation of red-emitting CsPbI3 QDs with experimental details for solar device applications

A class of semiconducting materials namely inorganic Cesium (Cs)-based halide perovskites has attracted the research society due to their interesting electronic and optical behavior creating the interest of researchers to explore these materials in the domain of optoelectronics. In this context, red-emitting CsPbI₃ quantum dots (QDs) exhibiting unique optical and electronic properties are of great interest to explore. Here, we have investigated the optical and electronic properties of CsPbI₃ QDs by utilizing density functional theory (DFT) study with experimental insight. The morphological investigation of CsPbI₃ QDs provide a lattice parameter (a) value of 6.031 Å (a=b=c) with volume 219.365 ų. The calculated value of the lattice parameter from X-ray diffraction (XRD) is 6.079 Å which is in match with the theoretically calculated lattice parameter value. A sharp luminescence around 1.85 eV can be seen from the photoluminescence (PL) plot indicating the red-emitting behavior of CsPbI₃ QDs. Band structure calculation was carried out to envisage the electronic properties. An energy gap of 1.38 eV has been computed at the middle point of the Brillouin zone having a direct bandgap semiconducting nature. Furthermore, the absorption coefficient has been evaluated to study the optical behavior of CsPbI₃ QDs. The observed spectrum shows its presence in the visible region. Also, the edge of the absorption plot around 1.36 eV indicates the bandgap of CsPbI₃ QDs is in agreement with the energy gap computed from the band structure. These computational results along with experimental insight suggest that this material can be utilized in the domain of optoelectronics and solar cells.