Anisotropic Luminophore Emission for Enhanced Light Trapping in Luminescent Solar Concentrator Waveguides

Control over the concentration of light is of great importance for many optical systems. Light-emitting diodes (LEDs), lasers, and optical amplifiers necessitate control over the emission of light inside and out of the system. Optical sensors, detectors, and photovoltaic systems typically benefit from light trapping. To achieve enhanced light trapping in an optical waveguide, we demonstrate anisotropic luminophore emission in a luminescent solar concentrator (LSC) waveguide geometry. By embedding CdSe-CdZnS nanoplatelet emitters into high-index TiO2 nanocylinders, we alter their angular emission profile to increase emission into total internal reflection (TIR) angles. The emission direction can be controlled by optimizing Mie-like multipolar resonances in the individual nanocylinders and the interaction with the lattice. Angle-resolved photoluminescence measurements on the fabricated nanocylinder arrays corroborate this understanding. By optimizing the cylinder shape and lattice spacing, we show an increase in emission into TIR angles from 75% (isotropic emission) to 83.5%. This novel approach to the integration of nanoscale photonic structures and emitters paves the way for enhanced emission control in photovoltaic systems, as well as in solid-state lighting and smart displays.