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A Photoelectrochemical Device with Dynamic Interface Energetics: Understanding of Structural and Physical Specificities and Improvement of Performance and Stability
Author(s) -
Jung JinYoung,
Yu JinYoung,
Yoon Sanghwa,
Yoo Bongyoung,
Lee JungHo
Publication year - 2018
Publication title -
advanced sustainable systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.499
H-Index - 24
ISSN - 2366-7486
DOI - 10.1002/adsu.201800083
Subject(s) - non blocking i/o , electrolyte , materials science , photocurrent , nanocrystal , oxide , porosity , chemical engineering , electrochemistry , nanotechnology , electrode , chemistry , optoelectronics , composite material , metallurgy , engineering , biochemistry , catalysis
The basic configuration of a photoelectrochemical (PEC) water splitting device contains a semiconductor junction, which separates charge carriers by developing interface energetics. Recently, porous metal oxide/semiconductor junctions have shown that flat‐band potentials ( V fb ), representing interface energetics, could be dynamically changed with PEC reactions. However, it remains unclear as to what structural and physical specificities of the porous metal oxide induce the dynamic V fb . Herein, it is demonstrated that the electrolyte permeability and nanocrystal structure of porous NiO x are crucial for the dynamic V fb in porous NiO x integrated Si photocathodes. A comparison of the dense and porous NiO x with electrolyte impermeable and permeable features, respectively, shows that V fb changes only in the porous NiO x . The porous NiO x also exhibits a nanocrystal structure and increased V fb values with a decrease in nanocrystal size. As a result of the increased V fb , the porous NiO x achieves much higher PEC performance compared to that of the dense NiO x . However, electrolyte permeability causes electrochemical decomposition of the Si component. Thus, a cointegration of the porous and dense NiO x bilayers, which ensures stable PEC operation for 10 h while achieving high potentials of 0.2 V versus reversible hydrogen electrode at a photocurrent of 10 mA cm −2 , is proposed.