Photoelectrochemical Properties of Heterojunction CdTe/TiO2 Electrodes Constructed Using Highly Ordered TiO2 Nanotube Arrays
Photoelectrochemical Properties of Heterojunction CdTe/TiO2 Electrodes Constructed Using Highly Ordered TiO2 Nanotube Arrays
复制标题
DOI：
10.1021/cm8010666
复制
发表时间：
2008-08-26
影响因子：
8.6
通讯作者：
Choi, Kyoung-Shin
中科院分区：
文献类型：
--
作者：
Seabold, Jason A.;Shankar, Karthik;Choi, Kyoung-Shin
采用电化学方法在二氧化钛纳米管阵列的管子和管间空隙中填充CdTe，制备了异质结CdTe/TiO2光电极。本文所用的二氧化钛纳米管阵列是通过氧化钛膜制备的，得到了紧密排列的n型二氧化钛管，其平均内径为50 nm，壁厚约为13 nm。长度为250-300 nm。以二氧化钛纳米管为工作电极，在85℃(~3H(+)+Cd~(2+)+HTeO_2+6E(-)->；Cd~(2+)+2H(2)O)下，在E=-0.4V vs Ag/AgCl条件下进行了阴极沉积。得到的电极包含三维有序的CdTe/TiO2结结构，结面积显著增强。与直接沉积在导电衬底(即掺氟氧化锡)上的二维CdTe层相比，形成的CdTe/TiO2结改善了CdTe层的光电流产生和光稳定性。通过本研究开发的一种新的沉积技术，形成了更紧密和共形的CdTe/TiO2结，该技术促进了仅在TiO2管中沉积CdTe，同时最大限度地减少了管入口处的沉积，从而防止了孔堵塞。用这种新工艺制备的CdTe/TiO2光电极在CdTe层中产生了更长的光路长度，同时增加了CdTe/TiO2层和CdTe/电解液结区。这导致了增强的光子吸收和光电流产生，使用最少量的镉来实现。
A heterojunction CdTe/TiO2 photoelectrode was prepared by electrochemically filling the tubes and tube-to-tube voids of a TiO2 nanotube array with CdTe. The TiO2 nanotube arrays used in this study were prepared by anodizing titanium films, which resulted in closely packed n-type TiO2 tubes with an average inner pore diameter of 50 nm, wall thickness of approximately 13 nm. and length of 250-300 nm. CdTe was cathodically deposited using TiO2 nanotubes as the working electrode at E = -0.4 V vs Ag/AgCl at 85 degrees C (3H(+) + Cd2+ + HTeO2+ + 6e(-) -> CdTe + 2H(2)O). The resulting electrodes contained three-dimensionally organized CdTe/TiO2 junction structures with significantly enhanced junction areas. Formation of the CdTe/TiO2 junction improved the photocurrent generation and photostability of the CdTe layer when compared with a two-dimensional CdTe layer deposited directly on a conducting substrate (i.e., fluorine-doped tin oxide). A more intimate and conformal CdTe/TiO2 junction was formed via a new deposition technique developed in this study that promotes deposition of CdTe only in the TiO2 tubes while minimizing deposition at the tube entrances, thus preventing pore clogging. The CdTe/TiO2 electrodes prepared by the new technique created a longer path length for light in the CdTe layer as well as increased CdTe/TiO2 and CdTe/electrolyte junction areas. This resulted in enhanced photon absorption and photocurrent generation, achieved using a minimal amount of CdTe.