Plasmon-Enhanced Blue Photoluminescence Efficiency from CsPb(Br/Cl)₃Perovskite Nanocrystals by Silver Nanoparticles

Cesium lead mixed-halide perovskite nanocrystals (NCs) incorporated with Ag nanoparticles (NPs) (Ag@CsPb(Br/Cl)3 NCs) were synthesized from starting solutions in the presence of Ag NPs. PL spectra showed that the incorporation of the Ag NPs in CsPb(Br/Cl)3 NCs had significantly increased the blue emission intensities and enhanced the PLQYs from 43 to 77%. The incorporation of the Ag NPs in CsPb(Br/Cl)3 NCs modified the radiative rate, increased effective energy transfer, and then enhanced the quantum yields of blue-emitting CsPb(Br/Cl)3 NCs. Numerical simulations based on the optical constants determined by ellipsometric measurements for bare and Ag@CsPb(Br/Cl)3 NCs revealed that the electric field maximums increase with increasing the size and the number of Ag NPs. However, excessive Ag NPs can reduce the quantum yields of blue emission. The changes in electric field strength correspond to the emission properties of CsPb(Br/Cl)3 NCs. Ag NPs can enhance the plasmon coupling and show a strong field enhancement effect. The improvement in blue emission from CsPb(Br/Cl)3 NCs is attributed to more effective energy transfer and the localized surface plasmon effect of the Ag NPs. These results indicate that this type of Ag@CsPb(Br/Cl)3 NC has great potential for the development of highly efficient blue-emitting devices.