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

Abstract 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.