Stability Optimization of 0D Cs3Cu2Cl5 Single Crystal with High Green Emission for Optoelectronics

Cs 3 Cu 2 Cl 5 is unstable owing to ionic migration and lattice decomposition in the atmosphere. In addition, obtaining large bulk single crystals of Cs 3 Cu 2 Cl 5 is challenging. Herein, a novel strategy is proposed for synthesizing a Cs 3 Cu 2 Cl 5 single crystal that exhibits excellent crystallinity and photoluminescence (PL) properties using an antisolvent-assisted method. Na + is doped into the Cs 3 Cu 2 Cl 5 lattice to replenish the lattice defects caused by chlorine vacancies, thus leading to stronger chemical interactions between Cu + and Cl − ions. Moreover, Na + doping circumvents ionic migration and lattice decomposition, thereby enhancing the PL intensity and maintaining the long-term stability of Cs 3 Cu 2 Cl 5 in the atmosphere. Incorporating 10% Na + into the Cs 3 Cu 2 Cl 5 lattice enhances the PL intensity by 18%, and the high-stability PL can maintain more than 48.5% of the PL intensity after 90 d in an atmospheric environment. In addition, a white light-emitting device (LED) is fabricated using the 10% Na + -doped Cs 3 Cu 2 Cl 5 crystal powder and it exhibits a high color-rendering index (93.7) and correlated color temperature (7120 K). Additionally, it exhibits superior stability, even at a high temperature of 120 °C. Thus, the excellent high-temperature stability of Cs 3 Cu 2 Cl 5 can promote its practical application in LED.