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Updated: Dec 12, 2025

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids
Published on: August 23, 2012
Spontaneous solar water splitting with decoupling of light absorption and electrocatalysis using silicon back-buried
Hui-Chun Fu1,2,3, Purushothaman Varadhan1,2, Chun-Ho Lin1
1Computer, Electrical, and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology, (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Abstract:
Converting sunlight into a storable form of energy by spontaneous water splitting is of great interest but the difficulty in simultaneous management of optical, electrical, and catalytic properties has limited the efficiency of photoelectrochemical (PEC) devices. Herein, we implemented a decoupling scheme of light harvesting and electrocatalysis by employing a back-buried junction (BBJ) PEC cell design, which enables >95% front side light-harvesting, whereas the electrochemical reaction in conjunction with carrier separation/transport/collection occurs on the back side of the PEC cell. The resultant silicon BBJ-PEC half-cell produces a current density of 40.51 mA cm-2 for hydrogen evolution by minimizing optical, electrical, and catalytic losses (as low as 6.11, 1.76, and 1.67 mA cm-2, respectively). Monolithic fabrication also enables three BBJ-PEC cells to be connected in series as a single module, enabling unassisted solar water-splitting with a solar-to-hydrogen conversion efficiency of 15.62% and a hydrogen generation rate of 240 μg cm-2 h-1.
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