Brightened Bicomponent Perovskite Nanocomposite Based on Förster Resonance Energy Transfer for Micro‐LED Displays

Lead halide perovskite quantum dots (PQDs) are making their way toward next-generation display applications, such as serving as color conversion layers in micro-light-emitting-diode (micro-LED) arrays. Red PQDs containing iodine exhibit weaker brightness compared with their green counterpart when employed as color conversion layers. Therefore, PQDs with enhanced brightness are highly favorable for micro/mini-LED displays. A universal strategy of bicomponent perovskite nanocomposite (BPNC) with significantly enhanced photoluminescence (PL) intensity is proposed through the built-in Förster resonance energy transfer (FRET) from the core CsPbBr3 to the shell γ-CsPbI3 , and it is confirmed that it is through a pair of combined quasi-degenerate energy levels in the blue spectra region that the FRET is conducted, resulting in a high excitation wavelength selectivity. Owing to the highly efficient energy transition route from blue excitation to red emission established by the FRET, the BPNC exhibits the brightest single-peak red photoluminescence with near 100% quantum yield. The BPNC with FRET is further proven to be adaptable to a wide range of emission wavelengths. The BPNCs in a blue micro-LED array are employed as color downconversion layers, and excellent color conversion properties and high color gamut are demonstrated. This strategy of BPNC paves a road to the full-color micro-LED displays.