Full‐Spectrum Liquid‐Junction Quantum Dot–Sensitized Solar Cells by Integrating Surface Plasmon–Enhanced Electrocatalysis

Full-spectrum solar energy utilization is the ultimate goal of high-performance photovoltaic devices. However, the present approaches to enhance sunlight harvesting in the cost-effective quantum dot-sensitized solar cells mainly focus on the use of high-frequency photons with the long-wavelength sunlight being left behind. Here, a full-spectrum solar cell architecture is proposed and the near-infrared light-enhanced cell performance is demonstrated with a plasmonic and electrocatalytic dual-function CuS nanostructure electrode. In the CdS/CdSe quantum dot-sensitized solar cells, an enhancement factor as high as 15% in power conversion efficiency is obtained for the device with near-infrared part of 1-sun light irradiating from the counter electrode side and ultraviolet-visible part incidence from the photoanode side. Electrochemical characterizations show that the enhanced electrocatalytic activity toward polysulfide reduction is attributed to the better device performance. This may be due to the plasmon-induced photothermal effect and interfacial energy transfer from the counter electrode under the near-infrared light, which accelerate the preceding chemical reactions for polysulfide reduction and improve the charge transfer at the electrode-electrolyte interface. This strategy provides an alternative way to achieve a full-spectrum liquid-junction solar cell via the integration of plasmon-enhanced electrocatalysis into photovoltaics.