氧化铁光阳极界面内建电场调控强化光生电荷空间分离  

Manipulating interface built-in electric fields for efficient spatial charge separation in hematite-based photoanodes

作　　者：卯连连 邓豪 李明涛 沈少华 Lianlian Mao;Hao Deng;Mingtao Li;Shaohua Shen(International Research Center for Renewable Energy,State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]International Research Center for Renewable Energy,State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Science China Materials》2023年第2期603-613,共11页中国科学（材料科学（英文版）

基　　金：supported by the National Key Research and Development Program of China(2018YFB1502003);the National Natural Science Foundation of China(21875183);the Natural Science Basic Research Program of Shaanxi Province(2019JCW-10);the“Fundamental Research Funds for the Central Universities”;“The Youth Innovation Team of Shaanxi Universities”。

摘　　要：为了缓解氧化铁光阳极内部和表面的电荷复合,本文引入了一种界面电荷调控策略,利用界面内建电场(IEF)促进电荷的空间分离.水热生长的钛掺杂氧化铁(Hem)纳米棒通过简单的两步浸渍涂层过程,以石墨相氮化碳(g-C_(3)N_(4))和小的三氧化钼(MoO_(3))团簇进行修饰.与原始的Hem相比,得到的Hem/C_(3)N_(4)/MoO_(3)表现出显著增强的光电化学分解水性能,相对于可逆氢电极,在1.23 V时,光阳极电流密度从0.3 mA cm^(-2)显著提高到1.6 mA cm^(-2),入射光子-电流转换效率在300 nm时达到18.4%.结果表明,在Hem/C_(3)N_(4)/MoO_(3)异质结中引入IEF是通过调控界面电荷特性实现的,此界面电荷特性是由Hem/C_(3)N_(4)界面的TypeⅡ能带排列和光阳极表面增强的能带弯曲所引起的,IEF能显著促进电荷的空间分离.研究这一界面电荷调控过程能为基于氧化铁的光阳极和其他半导体器件提供一种简单有效的策略,通过缓解载流子传输动力学的瓶颈,促进电荷的空间分离,实现高效的太阳能转换.Herein,a novel strategy of interface charge modulation for manipulating interface built-in electric fields(IEFs)and boosting spatial charge separation is introduced to alleviate charge recombination in the bulk and at the surface of hematite photoanodes.Hydrothermally grown Ti-doped hematite(Hem)nanorods are decorated with graphitic carbon nitride(g-C_(3)N_(4))species and small molybdenum oxide(MoO_(3))clusters using a facile two-step dip-coating process.Compared with the pristine Hem,the obtained Hem/C_(3)N_(4)/MoO_(3)exhibits increased photoelectrochemical water splitting performance with its photoanodic current density remarkably increased from 0.3 to 1.6 mA cm^(-2)at 1.23 V versus reversible hydrogen electrode(RHE)and incident photon-to-current conversion efficiency reaching 18.4%at 1.23 V versus RHE at 300 nm.The IEFs are introduced in the Hem/C_(3)N_(4)/MoO_(3)heterojunction by modulating the interfacial charge property via a typeⅡband alignment at the Hem/C_(3)N_(4)interface and an enhanced band bending at the surface of the photoanode,which substantially promote the spatial charge separation.By relieving the bottleneck of charge carrier transfer dynamics,this work in interfacial charge modulation provides a facile and effective strategy to boost the spatial charge separation in Hem-based photoanodes and other semiconducting devices for efficient solar energy conversion.

关 键 词：太阳能转换 阳极电流密度 半导体器件 能带弯曲 入射光子 石墨相氮化碳 载流子传输 氢电极 

分 类 号：TM914.4[电气工程—电力电子与电力传动]