Department of Chemistry, University of Rochester, Rochester, NY 14627.
Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627.
Proc Natl Acad Sci U S A. 2017 Oct 24;114(43):11297-11302. doi: 10.1073/pnas.1712325114. Epub 2017 Oct 9.
The present study reports the fabrication of CdSe quantum dot (QD)-sensitized photocathodes on NiO-coated indium tin oxide (ITO) electrodes and their H-generating ability upon light irradiation. A well-established spin-coating method was used to deposit CdSe QD stock solution onto the surface of NiO/ITO electrodes, thereby leading to the construction of various CdSe QD-sensitized photocathodes. The present report includes the construction of rainbow photocathodes by spin-coating different-sized QDs in a sequentially layered manner, thereby creating an energetically favorable gradient for charge separation. The resulting rainbow photocathodes with forward energetic gradient for charge separation and subsequent electron transfer to a solution-based hydrogen-evolving catalyst (HEC) exhibit good light-harvesting ability and enhanced photoresponses compared with the reverse rainbow photocathodes under white LED light illumination. Under minimally optimized conditions, a photocurrent density of as high as 115 μA⋅cm and a Faradaic efficiency of 99.5% are achieved, which is among the most effective QD-based photocathode water-splitting systems.
本研究报告了在 NiO 涂覆的氧化铟锡（ITO）电极上制备 CdSe 量子点（QD）敏化光阴极及其在光照下产生 H 的能力。采用成熟的旋涂法将 CdSe QD 储备溶液沉积在 NiO/ITO 电极表面，从而构建了各种 CdSe QD 敏化光阴极。本报告包括通过顺序层积不同尺寸的 QD 来构建彩虹光阴极，从而为电荷分离创造了有利的能量梯度。与在白色 LED 光照射下的反向彩虹光阴极相比，具有正向能量梯度的分离电荷和随后向基于溶液的析氢催化剂（HEC）转移电子的彩虹光阴极具有良好的光捕获能力和增强的光响应。在最小优化条件下，实现了高达 115 μA·cm 的光电流密度和 99.5%的法拉第效率，这是最有效的基于 QD 的光解水系统之一。
