Simultaneous improving luminescence intensity and stability of CsPbBr₃:SCN⁻@Eu/Zr-Uio-66-NH₂ with tunable emissions from blue to green and applications in indoor photovoltaics

The construction of stable and efficient materials that emit blue and green light remains a challenge. Among the blue light materials reported, metal-organic framework (MOF) materials are rarely reported as blue phosphors due to their weak luminescence intensity. Based on the construction of CsPbBr₃@MOF (CPB@MOF), an innovative idea was proposed to simultaneously enhance the green luminescence of CPB and the blue luminescence of MOF through the interaction between CPB and MOF for the first time. As expected, the blue luminescence from CPB:7%SCN⁻@0.5%MOF:Eu as well as the green luminescence from 5%CPB:7%SCN⁻@MOF:Eu was sufficient to construct high-performance light-emitting diode (LED) devices and further excite solar cells to generate stable photoelectric signals. The white LED (WLED) device with excellent color quality (color rendering index (CRI) = 96.2) and correlated color temperature (CCT = 9688 K) can be constructed by using the obtained blue-emitting CPB:7%SCN^-@0.5%MOF:Eu, green-emitting 5%CPB:7%SCN⁻@MOF:Eu, and red-emitting PPB:30%Mn²⁺. The density functional theory (DFT) theoretical calculation results indicate that the p orbital of Pb plays the major role in the conduction band, and the p orbital of Br plays the major role in the valance band of CPB and CPB:SCN⁻. While the p orbital of O plays the major role in both the conduction band and valance band of MOF. The heat capacity of CPB and CPB:SCN⁻ separately reaches the Dulong–Petit limit at 200 and 400 K, indicating that the thermal stability of CsPbBr₃ increases after SCN⁻ doping.