Eco‐Friendly, High‐Loading Luminescent Solar Concentrators with Concurrently Enhanced Optical Density and Quantum Yields While Without Sacrificing Edge‐Emission Efficiency

A luminescent solar concentrator (LSC) consists of loaded luminophores and a waveguide that can concentrate direct and diffuse sunlight, which is a crucial ingredient for developing solar glasses. In general, the loading concentration in LSCs is strongly restricted (typically <1 wt.%) to mitigate concentration‐induced quenching (CIQ), reabsorption losses, and aggregation‐induced scattering (AIS). However, this will induce transmission losses in particular for thin‐film LSCs. To address all aforementioned issues, large‐Stoke‐shift LSCs with different loadings are simply prepared based on thiolated gold nanoclusters (GSH‐AuNCs) dispersed in the polyvinylpyrrolidone (PVP) matrix. In contrast to conventional luminophores with a severe CIQ effect, photoluminescence quantum yields (PL‐QYs) can be significantly enhanced up to ≈25% (from 0.5 to 1%) even under high loading of ≈26 wt.%. Such PL‐QY enhancement is attributed to the synergistic effects of the suppression of non‐radiative relaxation and enhancement of radiative decay processes due to surface ligand‐matrix coordination. In addition, our high‐loading LSCs also exhibit excellent optical quality and film uniformity without introducing noticeable AIS effects. Thanks to those unique properties, eco‐friendly LSCs with high optical density can still hold a high edge‐emission efficiency of ≈70% due to minimal reabsorption and scattering losses, yielding an external quantum efficiency of ≈15% at the wavelength of 400 nm.