Hybrid Systems Based on Porous Silicon Photonic Crystals, Liquid Crystals, and Quantum Dots

Abstract

Photonic crystals based on porous silicon (pSi) are of much interest for both basic and applied research. Embedding luminophores into these structures allows controlling their emissive properties, which holds promise for laser and display applications, as well as for investigation of light–matter interaction. At the same time, the development of photonic crystals in which the spectral position of the photonic band gap can be shifted by external factors offers prospects for designing new photonic and optoelectronic materials. In this study, we suggest a technology for the fabrication of hybrid systems based on quantum dots (QDs) and photochromic liquid crystalline nematic mixtures embedded into pSi microcavities (MCs). When QDs are embedded into the MC, their photoluminescence (PL) spectrum narrows due to the Purcell effect and weak coupling between the exciton transitions in the QDs and the eigenmode of the pSi MC. Exposure to UV light causes a long-wavelength shift of the PL spectrum of the hybrid structure, whereas exposure to visible light shifts the spectrum back towards shorter wavelengths. This photo-optical response can be used to control the PL properties of the hybrid systems and design new photonic, optoelectronic, and sensing devices on their basis.