# Boosting fluorescence efficiency via filling technique prepared photonic crystal composites

## TL;DR

A new method boosts fluorescence in optical devices by using a composite structure with gold-doped crystals and silica, significantly enhancing light signals.

## Contribution

A filling technique is introduced to create a composite that enhances fluorescence by 242-fold through precise control of particle distances.

## Key findings

- The filling technique prevents fluorescence quenching by separating Au NPs and quantum dots.
- The IOPC-OPC composite boosts fluorescence intensity 242-fold compared to existing methods.
- The composite leverages plasmon resonance and photonic band gaps for efficient light modulation.

## Abstract

Au-doped photonic crystals offer considerable potential for boosting optical signals, however, precisely controlling the distance between luminescent particles and Au nanoparticles (NPs) faces severe challenges. We proposed a “filling” technique to prepare porous Au-doped inverse-opal PC (IOPC) with encapsulated Au NPs uniformly dispersing in insulating silica. The effective separation between Au NPs and infiltrated luminescent quantum dots successfully addresses the issue of fluorescence quenching, enhancing the photoluminescence intensity by 106-fold. Additionally, the double-layer IOPC-OPC composite, integrating an Au-doped IOPC and an opal photonic crystal (OPC) completely reflecting excitation or emission light, significantly improves the fluorescence intensity to 242-fold, far superior to the published counterparts. This synergy of localized surface plasmon resonance, high density of state, and photonic band gap in the IOPC-OPC composite offers an effective and low-loss approach for the precise modulation and amplification of photoluminescence. This strategy is crucial for the development of next-generation optical devices with improved sensitivity and stability.