Analysis of charge trapping and long lived hole generation in SrTiO 3 photoanodes
Analysis of charge trapping and long lived hole generation in SrTiO 3 photoanodes
复制标题
SrTiO 3 光阳极中的电荷捕获和长寿命空穴生成分析
DOI：
10.1039/d3se00886j
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发表时间：
2023
影响因子：
5.6
通讯作者：
Wilson A
中科院分区：
文献类型：
--
作者：
Wilson A
在施加偏压下对 SrTiO3 的电荷载流子动力学研究提供了获得独特见解的机会，了解支撑其最先进的光催化水分解活性的因素。在此，采用时间分辨光谱测量来研究施加偏压对 SrTiO3 在 μs-s 时间尺度上的瞬态和稳态载流子动力学的影响，并同时测量电荷提取动力学。 SrTiO3 光阳极中存在高密度的 Ti3+ 缺陷态，这与普遍的电子俘获到深态有关，这与电子提取竞争并限制了光电流。尽管被捕获的电子密度很高，但即使在没有施加偏压的情况下，使用瞬态吸收光谱观察到 SrTiO3 光阳极中光生空穴本质上具有较长的寿命。这对于克服与水氧化反应相关的缓慢动力学和空穴积累以及在无法施加偏压的光催化系统中实现良好性能非常重要。
Charge carrier dynamics studies of SrTiO3 under applied bias offer the opportunity to gain unique insights into what underpins its state-of-the-art photocatalytic water splitting activity. Herein, time resolved spectroscopic measurements are employed, to investigate the impact of applied bias on the transient and steady state charge carrier dynamics of SrTiO3 across μs–s timescales, and simultaneously measure charge extraction kinetics. A high density of Ti3+ defect states in SrTiO3 photoanodes are identified and associated with prevalent electron trapping into deep states, which is in competition with electron extraction and limits the photocurrent. Despite the high density of trapped electrons, an intrinsically long lifetime for photogenerated holes in SrTiO3 photoanodes is observed using transient absorption spectroscopy, even in the absence of applied bias. This is important for overcoming the slow kinetics and hole accumulation associated with the water oxidation reaction, and for enabling good performance in photocatalytic systems where bias cannot be applied.