Perovskite CsPbBr<sub>3</sub> Quantum Dots on Aminated\nSilica with Enhanced Stability for Blue Light-Emitting Diode and Anti-Counterfeiting\nApplications

Inorganic perovskite quantum dots (PQDs), specifically\nCsPbX<sub>3</sub> (X = Cl, Br, or I), have attracted considerable\ninterest\nfor their exceptional optoelectronic properties. However, their development\nis constrained by instability arising from particle mobility. The\ntendency of small-sized PQDs to aggregate into larger green-emitting\nPQDs presents a significant challenge to the widespread application\nof blue-emitting CsPbBr<sub>3</sub> PQDs, particularly in scenarios\ndemanding pure blue light emission. To tackle this challenge, we utilized\na straightforward yet efficient synthesis approach to immobilize and\nencapsulate blue-emitting CsPbBr<sub>3</sub> PQDs onto APTES-capped\nsilica microspheres. In contrast to CsPbBr<sub>3</sub> PQDs, CsPbBr<sub>3</sub>-A-SiO<sub>2</sub> composites display outstanding stability\nunder UV exposure, heat, and aqueous conditions, consistently maintaining\na single blue emission peak in the photoluminescence spectrum, accompanied\nby an extended fluorescence lifetime. Transmission electron microscope\nanalysis revealed the transformation of CsPbBr<sub>3</sub> from dispersed\nquantum dots to aggregated nanostructures or nanorods with time, while\nencapsulated quantum dots maintained uniform dispersion. By encapsulating\nCsPbBr<sub>3</sub>-A-SiO<sub>2</sub> composites on a 310 nm UV chip,\nstable blue light-emitting diodes with color coordinates approximately\nat (0.148, 0.05) can be fabricated. The synergistic application of\nunstable CsPbBr<sub>3</sub> PQDs and stable CsPbBr<sub>3</sub>-A-SiO<sub>2</sub> composites effectively enhance anticounterfeiting measures,\ninformation encryption, and digital display technologies. Integrating\nstable and unstable materials is anticipated to show promise in information\nencryption, security, and various other domains.