Three-dimensional macroporous photonic crystal enhanced photon collection for quantum dot-based luminescent solar concentrator

A luminescent solar concentrator (LSC) is a photon managing device that can harvest, direct and concentrate solar light to small areas, enabling subsequent coupling to photovoltaic devices (PVs) for enhanced solar energy conversion. However, the intrinsic photon loss through the so-called escape cone of the LSCs significantly limits their light harvesting and concentrating performance. In this work, we introduce a facile and low-cost approach for the fabrication of a three-dimensional (3D) macroporous photonic crystal (PC) filter as an efficient photon reflector, which can be coated onto quantum dot (QD) based LSC devices. We demonstrate that by controlling the PC reflection band to match the emission profile of the QD emitters, the light trapping efficiency of the PC coated LSC (PC-LSC) can be significantly improved from 73.3% to 95.1% as compared to the conventional PC-free LSC due to the reduced escape cone photon loss. In addition, we have developed a simulation model that considers the PC reflector effect. Both experimental and simulation results show that the enhancement in LSC device performance induced by the PC reflector increases with increasing dimension. In fact, simulation data predicts a maximum of 13.3-fold enhancement in external quantum efficiency (EQE) and concentration factor (C factor) of the PC-LSC under more ideal conditions. Moreover, the simulation result offers insight into the relationship between photon output efficiencies and the geometric design of the PC-LSC. Our study sheds light on future design and fabrication of LSC devices with enhanced photon collection and concentrating efficiencies through novel and wavelength-selective photon reflectors.