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Atomically Altered Hematite for Highly Efficient Perovskite Tandem Water‐Splitting Devices
Author(s) -
John Rohit Abraham,
Boix Pablo P.,
Yi Chenyi,
Shi Chen,
Scott M. C.,
Veldhuis Sjoerd A.,
Minor Andrew M.,
Zakeeruddin Shaik M.,
Wong Lydia Helena,
Grätzel Michael,
Mathews Nripan
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201700159
Subject(s) - photocurrent , water splitting , hematite , atomic layer deposition , materials science , energy conversion efficiency , tandem , perovskite (structure) , chemical engineering , hydrothermal circulation , perovskite solar cell , chemical bath deposition , nanotechnology , band gap , chemistry , optoelectronics , catalysis , layer (electronics) , photocatalysis , metallurgy , biochemistry , engineering , composite material
Photoelectrochemical (PEC) cells are attractive for storing solar energy in chemical bonds through cleaving of water into oxygen and hydrogen. Although hematite (α‐Fe 2 O 3 ) is a promising photoanode material owing to its chemical stability, suitable band gap, low cost, and environmental friendliness, its performance is limited by short carrier lifetimes, poor conductivity, and sluggish kinetics leading to low (solar‐to‐hydrogen) STH efficiency. Herein, we combine solution‐based hydrothermal growth and a post‐growth surface exposure through atomic layer deposition (ALD) to show a dramatic enhancement of the efficiency for water photolysis. These modified photoanodes show a high photocurrent of 3.12 mA cm −2 at 1.23 V versus RHE, (>5 times higher than Fe 2 O 3 ) and a plateau photocurrent of 4.5 mA cm −2 at 1.5 V versus RHE. We demonstrate that these photoanodes in tandem with a CH 3 NH 3 PbI 3 perovskite solar cell achieves overall unassisted water splitting with an STH conversion efficiency of 3.4 %, constituting a new benchmark for hematite‐based tandem systems.