Zero-Dimensional Cadmium Halide with Broad Band Yellow Light Emission for White Light-Emitting Diodes

Recently, low-dimensional organic-inorganic metal halide perovskites acting as white light emitting materials have been widely studied in the field of optoelectronics and solid-state lighting due to their facile preparation and excellent optical characteristics. However, the luminescence efficiency and light stability of white Light-emitting diodes (WLEDs) were hindered by the re-absorption of mixing phosphors due to the difference of light decay. Herein, we reported a new zero-dimensional (0D) cadmium halide of (BAPPz)Cd2Br8·2H2O with [CdX4]2- as optically active center which emits broadband yellow light for the first time and whose PLQY is 13.78%. Significantly, (BAPPz)Cd2Br8·2H2O can be used as a new phosphor for white light-emitting diode doped with a trace of blue commercial phosphor, which achieves a high color rendering index (CRI) of 93.7 and has the correlated color temperature (CCT) close to the domestic standard light source D65 (6500 K). With the driving current of the WLEDs device is increasing from 20 mA to 120 mA, the CRI values consistently maintain a high standard (> 90). This work not only demonstrates a new orientation to fabricate light-emitting diodes with high CRI values but also highlights its potential application in the development of energy-efficient white light-emitting diodes.