Room-Temperature Cross-Linking Enabled Perovskite Quantum Dots for Long Lifespan Blue Light-Emitting Diodes

Ultrasmall perovskite CsPbBr₃ quantum dots (QDs) with blue emission are promising materials for light-emitting diodes (LEDs). However, achieving room-temperature synthesis of blue-emitting CsPbBr₃ QDs with long-term stability remains a major challenge, hampering their real-world applications. Herein, we report a novel room-temperature strategy for synthesizing highly stable, blue-emitting CsPbBr₃ QDs, achieved with cross-linked network structures—marking a significant advancement over conventional approaches. Polymer (dimethyl siloxane dimethyl vinyl terminated (PDMS)) cross-linked by curing agent (dimethyl methyl hydrogen siloxane) offers networks that control the size of CsPbBr₃ QDs around 5 nm. The networks inhibit the fall-off of ligands from the QD surface, which restrains the agglomeration of QDs and mitigates thermal quenching of light emission. The CsPbBr₃ QDs with a photoluminescence quantum yield (PLQY) of 93% remain monodispersed in solution over 30 days. The QD-based films retain 95% of their initial PLQY after thermal treatment at 120°C. Blue-emitting CsPbBr₃ LEDs with an emission of 472 nm and a full-width at half-maximum (FWHM) of 23 nm exhibit a peak luminance of 4096 cd m⁻² and an excellent operational half-lifetime (T₅₀) over 38 h at 100 cd cm⁻², the longest-lifespan perovskite blue-quantum-dot LEDs reported to date.