Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
ACS Appl Mater Interfaces. 2017 Dec 20;9(50):43614-43622. doi: 10.1021/acsami.7b12564. Epub 2017 Dec 11.
Protective overlayers for light absorbers in photoelectrochemical water-splitting devices have gained considerable attention in recent years. They stabilize light absorbers which would normally be prone to chemical side reactions leading to degradation of the absorber. Atomic layer deposition (ALD) enables conformal and reproducible ultrathin protective layer growth even on highly structured substrates. One of the most widely investigated protective layers is amorphous TiO, deposited by ALD at a relatively low temperature (120-150 °C). We have deposited protective layers from tetrakis(dimethylamido)titanium(IV) at two different temperatures and investigated their chemical composition as well as optical and electrochemical properties. Our main findings reveal a change in the flat band potential with thickness, reaching a stable value of about -50 to -100 mV versus reversible hydrogen electrode for films >30 nm, with doping densities of ∼10 cm. Practical thicknesses to achieve pinhole-free films are evaluated and discussed.
近年来，用于光电化学水分解器件中光吸收体的保护层受到了相当多的关注。它们可以稳定光吸收体，否则光吸收体很容易发生导致吸收体降解的化学副反应。原子层沉积（ALD）能够在即使是高度结构化的衬底上进行保形和可重复的超薄保护层生长。研究最广泛的保护层之一是通过 ALD 在相对较低的温度（120-150°C）下沉积的非晶态 TiO。我们已经在两种不同的温度下沉积了来自四（二甲基氨基）钛（IV）的保护层，并研究了它们的化学组成以及光学和电化学性质。我们的主要发现表明，随着厚度的增加，平带电位发生了变化，对于 >30nm 的薄膜，其稳定值约为相对于可逆氢电极的-50 至-100mV，掺杂密度约为 10cm。评估和讨论了实现无针孔薄膜的实际厚度。
