Photoluminescence enhancement in wide spectral range excitation in CsPbBr3 nanocrystal/Ag nanostructure via surface plasmon coupling

This work demonstrates the surface plasmon (SP)-exciton coupling effect on the photoluminescence (PL) enhancement in CsPbBr3 nanocrystal (NC) at PMMA/Ag nanostructure (NS) in wide spectral range excitation. The spectra dependent time resolved PL measurement reveals that the emission photons are from the recombination of localized excitons and the PL enhancement can be attributed to the near-field effect, which is also supported by evidence that the enhancements are nearly the same in the whole excitation wavelength from 200 nm to 900 nm. The non-spectral dependence of the enhancement factor suggests that there is the same dynamic process of hot electrons in CsPbBr3 NC in multiphoton excitation. The hot electrons will relax into localized exciton states, and the electric field generated by SPs will enhance the radiative recombination of excitons. This work will have benefits for revealing dynamics of hot electron relaxing and interactions in multi-photon absorption, as well as the inner mechanism of SP coupling effects.