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

CsMnX 3 (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 (MnX 2 ). Addressing this challenge, a novel strategy for synthesizing large bulk of CsMnCl 3 ·2H 2 O 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 CsMnCl 3 ·2H 2 O 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 CsMnCl 3 ·2H 2 O can promote its practical application in optoelectronics .