Control of perovskite photoluminescence via the dipolar resonances induced by TiO2 nanocylinder arrays
Yu-Tsung Lin1*, Yen-Cheng Lu1, Pin Chieh Wu1
1Department of Photonics, National Cheng Kung University, Tainan, Taiwan
* Presenter:Yu-Tsung Lin,
Photoluminescent (PL) spectra provide a feasible channel to probe the mechanisms in perovskite films, which are critically important in solar cell and light-emitting diodes, such as efficiency of charge extraction, ion migration and transport, and light-emission properties. In order to control PL properties, most of prior studies focused on metallic nanostructures and nanoparticles with various sizes and featured geometries which are conducive for inducing surface plasmons. In this work, we proposed an alternative method to manipulate the PL emission from perovskite films by utilizing the specific resonances in TiO2 dielectric metasurface arrays, separately dominated by electrical, magnetic and toroidal dipoles. The optical spectra and Purcell effects of these resonances where possess different levels of electromagnetic field enhancements around the TiO2 nanostructures have been investigated by employing the numerical simulation as well as experimental measurements. Comparing with conventional Mie resonances, our results show that the PL intensity can be significantly enhanced when the emission wavelength spectrally overlapped with the toroidal dipolar resonance. Our findings remarkably expand present knowledge on resonant modes in high-index metasurfaces, revealing crucial conditions for highly efficient photon emission control.

Keywords: PL emission control, TiO2 metasurface, perovskite film