周期性极化铌酸锂上ZnO异质结构的光化学反应模式,ACS Applied Materials & Interfaces

当前位置： X-MOL 学术 › ACS Appl. Mater. Interfaces › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

周期性极化铌酸锂上ZnO异质结构的光化学反应模式
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2016-09-22 00:00:00 , DOI: 10.1021/acsami.6b06060
Manpuneet Kaur ₁ , Qianlang Liu ₁ , Peter A. Crozier ₁ , Robert J. Nemanich ₂

Affiliation

LiNbO _3中的内部电场为异质光催化反应提供了驱动力，其中光激发的空穴或电子可以参与正（+ c）和负（-c）畴表面以及畴边界处的氧化还原反应。表征表面化学反应性的一种方法是通过将LiNbO ₃浸入AgNO ₃水溶液中并用上述带隙光照射来测量光诱导的Ag沉积。Ag ⁺离子的还原导致在表面形成Ag纳米颗粒，并且高密度的Ag纳米颗粒表明表面光化学反应增强。在这项研究中，n型半导体ZnO层沉积在周期性极化的LiNbO _3上（PPLN）来调节表面电子特性并影响表面氧化还原反应。在PPLN基板上进行1、2、4和10 nm ZnO薄膜的等离子增强原子层沉积（PEALD）之后，将基板浸入AgNO ₃水溶液中并用带隙以上的紫外线照明。对于1和2 nm的ZnO / PPLN异质结构，Ag纳米粒子的密度增加，表明ZnO / PPLN表面的电子密度增加。但是，增加ZnO的厚度超过2 nm会导致Ag纳米颗粒密度的降低。纳米粒子密度的增加与ZnO / PPLN界面处的光激发电荷密度以及ZnO表面存在弱吸附的Stern层有关。对于较厚的ZnO，纳米颗粒密度的降低归因于ZnO层中的光激发电子筛选，从而抑制了电子从LiNbO ₃到ZnO表面的流动。

"点击查看英文标题和摘要"

Photochemical Reaction Patterns on Heterostructures of ZnO on Periodically Poled Lithium Niobate

The internal electric field in LiNbO₃ provides a driving force for heterogeneous photocatalytic reactions, where photoexcited holes or electrons can participate in redox reactions on positive (+c) and negative (−c) domain surfaces and at the domain boundaries. One method to characterize the surface chemical reactivity is to measure photoinduced Ag deposition by immersing the LiNbO₃ in an aqueous AgNO₃ solution and illuminating with above bandgap light. Reduction of Ag⁺ ions leads to the formation of Ag nanoparticles at the surface, and a high density of Ag nanoparticles indicates enhanced surface photochemical reactions. In this study, an n-type semiconducting ZnO layer is deposited on periodically poled LiNbO₃ (PPLN) to modulate the surface electronic properties and impact the surface redox reactions. After plasma enhanced atomic layer deposition (PEALD) of 1, 2, 4, and 10 nm ZnO thin films on PPLN substrates, the substrates were immersed in aqueous AgNO₃ and illuminated with above band gap UV light. The Ag nanoparticle density increased for 1 and 2 nm ZnO/PPLN heterostructures, indicating an enhanced electron density at the ZnO/PPLN surface. However, increasing the ZnO thickness beyond 2 nm resulted in a decrease in the Ag nanoparticle density. The increase in nanoparticle density is related to the photoexcited charge density at the ZnO/PPLN interface and the presence of a weakly adsorbed Stern layer at the ZnO surface. The decrease in the nanoparticle density for thicker ZnO is attributed to photoexcited electron screening in the ZnO layer that suppresses electron flow from the LiNbO₃ to ZnO surface.

更新日期：2016-09-22

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南