title: High-Performance a-Si/c-Si Heterojunction Photoelectrodes for Photoelectrochemical Oxygen and Hydrogen Evolution.
abstract: Amorphous Si (a-Si)/crystalline Si (c-Si) heterojunction (SiHJ) can serve as highly efficient and robust photoelectrodes for solar fuel generation. Low carrier recombination in the photoelectrodes leads to high photocurrents and photovoltages. The SiHJ was designed and fabricated into both photoanode and photocathode with high oxygen and hydrogen evolution efficiency, respectively, by simply coating of a thin layer of catalytic materials. The SiHJ photoanode with sol-gel NiOx as the catalyst shows a current density of 21.48 mA/cm(2) at the equilibrium water oxidation potential. The SiHJ photocathode with 2 nm sputter-coated Pt catalyst displays excellent hydrogen evolution performance with an onset potential of 0.640 V and a solar to hydrogen conversion efficiency of 13.26%, which is the highest ever reported for Si-based photocathodes.
authors: ‡Department of Electrical and Computer Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.|▽Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors: Hsin-Ping
authors: HP
authors: Wang
authors: ‡Department of Electrical and Computer Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.
authors: Ke
authors: K
authors: Sun
authors: ∥Materials Science and Engineering Program, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.
authors: Sun Young
authors: SY
authors: Noh
authors: ‡Department of Electrical and Computer Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.
authors: Alireza
authors: A
authors: Kargar
authors: Meng-Lin
authors: ML
authors: Tsai
authors: §Advanced Technology Department, AU Optronic Corporation, Taichung, Taiwan, Republic of China.
authors: Ming-Yi
authors: MY
authors: Huang
authors: ‡Department of Electrical and Computer Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.|∥Materials Science and Engineering Program, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.|⊥Qualcomm Institute, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.
authors: Deli
authors: D
authors: Wang
authors: ‡Department of Electrical and Computer Engineering, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States of America.
authors: Jr-Hau
authors: JH
authors: He
keywords: Si heterojunction photoelectrodes; hydrogen evolution; oxygen evolution; solar to hydrogen conversion efficiency; solar to oxygen conversion efficiency