Large-Area Transparent 'Quantum Dot Glass' for Building Integrated Photovoltaics

A concept of transparent “Quantum Dot Glass” (TQDG) is proposed for a combination of quantum dot (QD) based glass luminescent solar concentrator (LSC) and its edge-attached solar cells, as a type of transparent photovoltaics (TPV) for building-integrated photovoltaics (BIPV). Different from conventional LSCs, which typically serve as pure optical devices, TQDGs have to fulfill requirements both as power-generating components and building envelop construction materials. In this work, we demonstrate large-area (400 cm2) TQDGs based on environmentally benign silicon QDs in a triplex glass configuration. Balanced photovoltaic performance and aesthetic quality of the TQDGs were achieved by optimization of Si QDs/polymer interlayer thickness and QD loading in the devices. As a result, an overall electrical power conversion efficiency (PCE) of 1.57% was obtained with back-reflection for a highly transparent TQDG (average visible transmittance of 84%, with color rendering index of 94 and low haze ≤ 3%), contributing to a high light utilization efficiency (LUE) of 1.3%, which is among the top of reported TPVs based on LSC technology with similar size. Most importantly, these TQDGs are shown to have better thermal and sound insulation property compared to normal float glass, as well as improved mechanical performance and safety, which significantly pushes the TPV technology towards practical building integration and construction. TQDGs simultaneously exhibiting favorable photovoltaic, aesthetic and building-envelope characteristics, can serve as a multifunctional material for the realization of nearly zero-energy building concept.