Optically tunable quantum dots (QDs) have drawn significant attention for optoelectronic applications such as light-emitting diodes, photovoltaics, and photodetectors. However, when QDs are assembled as films, the quantum yield decreases significantly, known as the “self-quenching” effect. In this study, we develop a general method for suppressing this self-quenching effect and enhancing energy conversion efficiency using shell-isolated nanoparticles (SHINs), which efficiently promote spontaneous emission of diverse QD films to picosecond timescale. We discover that Ag SHINs with controllable thickness shells exhibit different enhancement factors due to the competition between radiative and non-radiative decay, and localized surface plasmon resonance (LSPR) in nanocavities enhances the fluorescence of QD monolayer films up to nearly 1000 times by SHINs with 6 nm shell. In addition, acting as nanoantennas and amplifying the local photon density, SHINs also effectively enhance excitons excitation and improve the H₂ evolution performance of QD-PEC to nearly 12 µmol/h in neutral solution without “hot” electrons effect.

光学可调量子点（QD）在光电应用中引起了极大的关注，例如发光二极管，光伏和光电探测器。但是，当量子点组装成薄膜时，量子产率会显着降低，这就是所谓的“自猝灭”效应。在这项研究中，我们开发了一种通用的方法，该方法使用壳隔离的纳米粒子（SHIN）抑制这种自猝灭效果并提高能量转换效率，该方法可有效地将各种QD薄膜的自发发射提高到皮秒级。我们发现，由于辐射衰减和非辐射衰减之间的竞争，具有可控制厚度的壳的Ag SHINs表现出不同的增强因子，纳米腔中的局部表面等离子体激元共振（LSPR）通过6 nm壳层SHIN将QD单层膜的荧光增强了近1000倍。此外，SHINs作为纳米天线并放大局部光子密度，还可以有效地增强激子的激发并改善H₂ QD-PEC在中性溶液中的演化性能接近12 µmol / h，没有“热”电子效应。