...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>ACS applied materials & interfaces >Insight into the Degradation Mechanisms of Atomic Layer Deposited TiO2 as Photoanode Protective Layer
【24h】

Insight into the Degradation Mechanisms of Atomic Layer Deposited TiO2 as Photoanode Protective Layer

机译：深入了解原子层沉积TiO2作为光电潮汐保护层的降解机制

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Around 100 nm thick TiO2 layers deposited by atomic layer deposition (ALD) have been investigated as anticorrosion protective films for silicon-based photoanodes decorated with 5 nm NiFe catalyst in highly alkaline electrolyte. Completely amorphous layers presented high resistivity; meanwhile, the ones synthesized at 300 degrees C, having a fully anatase crystalline TiO2 structure, introduced insignificant resistance, showing direct correlation between crystallization degree and electrical conductivity. The conductivity through crystalline TiO2 layers has been found not to be homogeneous, presenting preferential conduction paths attributed to grain boundaries and defects within the crystalline structure. A correlation between the conductivity atomic force microscopy measurements and grain interstitials can be seen, supported by high-resolution transmission electron microscopy cross-sectional images presenting defective regions in crystalline TiO2 grains. It was found that the conduction mechanism goes through the injection of electrons coming from water oxidation from the electrocatalyst into the TiO2 conduction band. Then, electrons are transported to the Si/SiOx/TiO2 interface where electrons recombine with holes given by the p(+)n-Si junction. No evidences of intra-band-gap states in TiO2 responsible of conductivity have been detected. Stability measurements of fully crystalline samples over 480 h in anodic polarization show a continuous current decay. Electrochemical impedance spectroscopy allows to identify that the main cause of deactivation is associated with the loss of TiO2 electrical conductivity, corresponding to a self-passivation mechanism. This is proposed to reflect the effect of OH- ions diffusing in the TiO2 structure in anodic conditions by the electric field. This fact proves that a modification takes place in the defective zone of the layer, blocking the ability to transfer electrical charge through the layer. According to this mechanism, a regeneration of the degradation process is demonstrated possible based on ultraviolet illumination, which contributes to change the occupancy of TiO2 electronic states and to recover the defective zone's conductivity. These findings confirm the connection between the structural properties of the ALD-deposited polycrystalline layer and the degradation mechanisms and thus highlight main concerns toward fabricating long-lasting metal-oxide protective layers for frontal illuminated photoelectrodes.
机译：已经研究了大约100nm厚的TiO 2层，被原子层沉积（ALD）沉积为硅基光池的防腐保护膜，以高碱性电解质装饰有5nm NiFe催化剂。完全无定形层呈现出高电阻率;同时，在300摄氏度中合成的，具有完全锐钛矿结晶TiO2结构，引入微不足道的抗性，显示结晶度和电导率之间的直接相关性。已经发现通过结晶TiO 2层的电导率不均匀，呈现归因于晶界和结晶结构内的缺陷的优先​​传导路径。可以看到导电原子力显微镜测量和晶粒间质术之间的相关性，通过高分辨率透射电子显微镜横截面图像，其呈现晶体TiO2晶粒的缺陷区域。发现导通机构通过从电催化剂的水氧化出来的电子进入TiO 2导带。然后，电子被传送到Si / SiOx / TiO2接口，其中电子重新组合通过P（+）N-Si结的孔。没有检测到在TiO2负责导电性的TiO2中的带内间隙状态的证据。在阳极偏振中超过480小时的完全结晶样品的稳定性测量显示连续电流衰减。电化学阻抗光谱允许识别失活的主要原因与TiO 2导电率的损失相关，对应于自钝化机制。提出了这一点以反映电场在阳极条件下在TiO2结构中扩散的OH-离子的影响。该事实证明，在层的缺陷区域中进行修改，阻挡通过层传递电荷的能力。根据该机制，基于紫外线照明进行降解过程的再生，这有助于改变TiO2电子国家的占用并恢复缺陷的区域的电导率。这些发现证实了ALD沉积的多晶层的结构特性和降解机制之间的连接，从而强调了对额外照射光电子的长持久金属氧化物保护层的主要问题。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号