Ultra-high quality red-emission lead-free single-crystal for optoelectronics

CsMnX3 (X = Cl, Br, I) metal halide materials are prone to dissociation in the atmosphere due to the hygroscopic nature of cesium halide (CsX) and manganese halide (MnX2). Addressing this challenge, a novel strategy for synthesizing large bulk of CsMnCl3·2H2O single crystals (SCs) using an anti-solvent-assisted method was presented. Importantly, the SCs have a sheet shape with dimensions of 22 mm × 9 mm × 2 mm, and demonstrate superior crystallinity and strong red emission at 630 nm. Furthermore, the electron localization function (ELF) diagram demonstrates that the robust electronegativity of O element, enhancing the thermal stability of the octahedral structure. Meanwhile, the crystals retained 85 % of their original value even after 90 days in an atmospheric environment. In addition, red light-emitting devices (LEDs) were fabricated using the CsMnCl3·2H2O single crystals, which shows the voltage, and Commission Internationale de lEclairage (CIE) color coordinates remained superior stable when the current changed from 100 to 200 mA. Thus, the excellent stability of CsMnCl3·2H2O can promote its practical application in optoelectronics. •A novel strategy for synthesizing a large bulk CsMnCl3·2H2O single crystal using an anti-solvent-assisted method, the single crystal have a sheet shape with dimensions of 22 mm × 9 mm × 2 mm, and demonstrate superior crystallinity and red emission at 630 nm.•The electron local function (ELF) diagram shows that the introduction of oxygen element enhances the thermal stability of the octahedral structure and orbital coupling.•The CsMnCl3·2H2O single crystal is used to manufacture red light-emitting devices (LEDs). When the current changes from 100 mA to 200 mA, the voltage and color coordinates maintain excellent stability.