Mesoporous silica-coated CsPbBr3:ZnBr2:NaBr nanocrystals with high photoluminescence and tunable wavelengths for micro light-emitting diodes†

For future displays and artificial light sources, coupling micro light-emitting diodes (μ-LEDs) with color conversion phosphors is among the most promising approaches; it calls for the emission wavelength of green emitters to be kept at 525–535 nm, and for them to have a narrow full width at half maximum (FWHM < 25 nm) with high stability, nanoscale size, and a high photoluminescence quantum yield (PLQY). However, current emitters struggle to match all the above criteria. Herein, we first synthesized a series of uniform mesoporous silica nanoparticles (MSNs), following a modified method, which were then employed as nano-templates for the confined growth of highly stable CsPbBr₃ nanocrystals (NCs) with precise green emission and a high PLQY. Using a dual-additive-assisted strategy, both ZnBr₂ and NaBr additives are introduced to synergistically tune green emission (≈525–535 nm), with a narrowest FWHM of as low as 21 nm and a highest PLQY of up to 99%. We have used the nanocomposites to prepare a uniform color conversion pattern with pixels of 100 μm, demonstrating their potential for μ-LED applications.