Zhu Kaijian, Frehan Sean K, Jaros Anna M, O'Neill Devin B, Korterik Jeroen P, Wenderich Kasper, Mul Guido, Huijser Annemarie
PhotoCatalytic Synthesis Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Optical Sciences Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2021 Jul 29;125(29):16049-16058. doi: 10.1021/acs.jpcc.1c03553. Epub 2021 Jul 16.
Dye-sensitized photoelectrochemical (DSPEC) water splitting is an attractive approach to convert and store solar energy into chemical bonds. However, the solar conversion efficiency of a DSPEC cell is typically low due to a poor performance of the photocathode. Here, we demonstrate that Cu-doping improves the performance of a functionalized NiO-based photocathode significantly. Femtosecond transient absorption experiments show longer-lived photoinduced charge separation for the Cu:NiO-based photocathode relative to the undoped analogue. We present a photophysical model that distinguishes between surface and bulk charge recombination, with the first process (∼10 ps) occurring more than 1 order of magnitude faster than the latter. The longer-lived photoinduced charge separation in the Cu:NiO-based photocathode likely originates from less dominant surface recombination and an increased probability for holes to escape into the bulk and to be transported to the electrical contact of the photocathode. Cu-doping of NiO shows promise to suppress detrimental surface charge recombination and to realize more efficient photocathodes.
染料敏化光电化学（DSPEC）水分解是一种将太阳能转化并存储为化学键的有吸引力的方法。然而，由于光阴极性能不佳，DSPEC电池的太阳能转换效率通常较低。在此，我们证明铜掺杂显著提高了功能化氧化镍基光阴极的性能。飞秒瞬态吸收实验表明，相对于未掺杂的类似物，铜掺杂氧化镍基光阴极的光生电荷分离寿命更长。我们提出了一个光物理模型，该模型区分了表面和体相电荷复合，其中第一个过程（约10皮秒）比第二个过程快1个多数量级。铜掺杂氧化镍基光阴极中光生电荷分离寿命更长，可能源于表面复合不那么占主导地位，以及空穴逃逸到体相并传输到光阴极电接触的概率增加。氧化镍的铜掺杂有望抑制有害的表面电荷复合，并实现更高效的光阴极。
