Pure Tunable Emissions from Cesium Manganese Bromide by Monitoring the Crystal Fields Through a Sustainable Approach

Research on manganese (Mn) halide perovskite derivatives with tunable emissions and high color purity have gathered a significant amount of attention for display technology. Despite of mesmerizing optical properties, the synthesis of these all-inorganic Mn halide compounds is followed by complex and toxic processes. Second, a precise control over the synthesis parameters is mandatory to achieve their pure emissions. Therefore, an ecologically sustainable water-based solution approach is adapted here to tailor the phases and emissions of cesium manganese bromide (Cs-Mn-Br) perovskite derivatives. It is observed that a controlled injection of solution stabilizer plays a pivotal role in engineering the intrinsic properties of Mn halide perovskites. This solution stabilizer interacts with the Mn-ions of those perovskite derivatives influencing their surrounding coordination environment and pure emission from then. A pure green emission with PLQY of 82% is achieved from as prepared Cs₃MnBr₅, whereas CsMnBr₃ showed a red emission with PLQY of ≈20%. Encouraged by these properties phosphor-driven light emitting diodes (LED) are designed that show a steady electroluminescence intensity. The CIE coordinates of the Cs₃MnBr₅ and CsMnBr₃ LED prototypes are at (0.224, 0.659) and (0.688, 0.316). This study showcases simple, eco-friendly tactics for developing green and red LED prototypes contributing toward sustainable device design.