Balog Ádám, Samu Gergely F, Kamat Prashant V, Janáky Csaba
Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre , University of Szeged , Rerrich Square 1 , Szeged H-6720 , Hungary.
ELI-ALPS Research Institute , Dugonics sq. 13 , Szeged 6720 , Hungary.
J Phys Chem Lett. 2019 Jan 17;10(2):259-264. doi: 10.1021/acs.jpclett.8b03242. Epub 2019 Jan 4.
Detailed mechanistic understanding of the optoelectronic features is a key factor in designing efficient and stable photoelectrodes. In situ spectroelectrochemical methods were employed to scrutinize the effect of trap states on the optical and electronic properties of CuI photoelectrodes and to assess their stability against (photo)electrochemical corrosion. The excitonic band in the absorption spectrum and the Raman spectral features were directly influenced by the applied bias potential. These spectral changes exhibit a good correlation with the alterations observed in the charge-transfer resistance. Interestingly, the population and depopulation of the trap states, which are responsible for the changes in both the optical and electronic properties, occur in a different potential/energy regime. Although cathodic photocorrosion of CuI is thermodynamically favored, this process is kinetically hindered, thus providing good stability in photoelectrochemical operation.
对光电特性的详细机理理解是设计高效稳定光电极的关键因素。采用原位光谱电化学方法来研究陷阱态对CuI光电极光学和电子性质的影响，并评估其对（光）电化学腐蚀的稳定性。吸收光谱中的激子带和拉曼光谱特征直接受到施加偏置电位的影响。这些光谱变化与电荷转移电阻中观察到的变化呈现出良好的相关性。有趣的是，负责光学和电子性质变化的陷阱态的填充和去填充发生在不同的电位/能量区域。虽然CuI的阴极光腐蚀在热力学上是有利的，但该过程在动力学上受到阻碍，从而在光电化学操作中提供了良好的稳定性。
