Composition-Graded ZnxCd1-xSe@ZnO Core-Shell Nanowire Array Electrodes for Photoelectrochemical Hydrogen Generation
Composition-Graded ZnxCd1-xSe@ZnO Core-Shell Nanowire Array Electrodes for Photoelectrochemical Hydrogen Generation
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DOI：
10.1021/jp204747w
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发表时间：
2012-02-09
影响因子：
3.7
通讯作者：
Fan, Hong Jin
中科院分区：
文献类型：
--
作者：
Li, Hongxing;Cheng, Chuanwei;Fan, Hong Jin
一维氧化物纳米结构阵列作为太阳能电池或光电化学（PEC）太阳能制氢应用中的光电极被广泛研究，对于这些应用，高度期望电极具有宽的光吸收和有效的电荷分离。本文采用温度梯度化学气相沉积（CVD）法在ZnO纳米线上沉积ZnxCd1-xSe层，制备了组分渐变的ZnxCd1-xSe@ZnO核壳纳米线阵列。核壳纳米线阵列光电极在样品表面产生从2.7（460 nm）到1.77 eV（700 nm）的连续吸收边。这种核-壳异质结构有利于光生电子-空穴对的分离和电子从ZnCdSe到ZnO的转移。通过使用这种核-壳纳米线阵列作为经由PEC电池的太阳能氢生成的光阳极，在1个太阳光照射下在零偏压下相对于Ag/AgCl实现了类似于5.6mA/cm（2）的光电流密度。这种方法可能是有用的多结纳米结构的半导体光电极的设计朝向更有效的太阳能燃料装置。
One-dimensional oxide nanostructure arrays are widely investigated as photoelectrodes in solar cells or photoelectrochemical (PEC) solar hydrogen generation applications, for which it is highly desirable for the electrode to have a broad light absorption and an efficient charge separation. In this work, a composition-graded ZnxCd1-xSe@ ZnO core-shell nanowire array is prepared through temperature-gradient chemical vapor deposition (CVD) of ZnxCd1-xSe layer onto the pregrown ZnO nanowires. The core shell nanowire array photoelectrodes yield a continuous absorption edge from 2.7 (460 nm) to 1.77 eV (700 nm) across the sample surface. The core-shell heterostructure facilitates the photogenerated electron-hole pair separation and the electron transfer from ZnCdSe to ZnO. By using such core-shell nanowire arrays as photoanodes for solar hydrogen generation via a PEC cell, a photocurrent density of similar to 5.6 mA/cm(2) is achieved under 1 sun solar light illumination at zero bias versus Ag/AgCl. This method may be useful in the design of multijunction nanostructured semiconductor photoelectrodes toward more efficient solar fuel devices.