<br>研究量子点/TiO2 复合材料的界面特性和物理吸附机制，实现高效、可持续的光诱导界面电子转移,ACS Applied Materials & Interfaces

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研究量子点/TiO2 复合材料的界面特性和物理吸附机制，实现高效、可持续的光诱导界面电子转移
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2024-02-09 , DOI: 10.1021/acsami.3c16086
Bumsoo Chon ₁ , Hyung Joo Lee ₁ , Yun Kang ₂ , Hyun Woo Kim ₂ , Chul Hoon Kim ₁ , Ho-Jin Son ₁

Affiliation

与传统分子染料相比，量子点（QD）/TiO ₂复合材料具有优异的稳定性，以及高紫外-可见光吸收能力（可通过尺寸调整覆盖大部分太阳光谱）作为各种太阳能转换系统的光敏成分正在被积极研究。然而，基于QD/TiO ₂的太阳能电池和光催化系统的转换效率和耐久性仍然不如采用有机/无机组分作为光敏剂的传统系统。这是因为量子点在TiO ₂表面上的吸附较差，导致两者之间的界面相互作用不足。 TiO ₂表面QD吸附的机制及其与光敏化过程的关系仍不清楚。在本研究中，我们确定TiO ₂半导体和QD的表面特性（即金属氧化物的表面缺陷和QD核的表面结构）直接影响TiO ₂的QD吸附能力以及之间的界面相互作用。 QDs和TiO ₂ ，涉及从光激发QDs到TiO _{2 的}光敏化过程(QD* → TiO ₂ )。当形状/厚度调制的三角形QD与富含缺陷的锐钛矿TiO ₂复合时，QD和TiO ₂之间的界面相互作用最大化。通过光动力分析和使用 X 射线光电子能谱 (XPS)、透射电子显微镜 (TEM) 和光催化实验的表面评估进行的综合研究共同验证了调节 QD 的表面性质和调节 TiO ₂缺陷浓度可以协同放大界面相互作用介于量子点和TiO ₂之间。这种增强显着提高了从光激发QD到TiO ₂的光诱导电子转移效率，从而显着提高了QD/TiO ₂复合材料的光催化活性。这项研究首次深入表征了分散在异质金属氧化物表面上的量子点的物理粘附力。此外，所制备的QD/TiO ₂复合材料表现出优异的吸附稳定性，在水性介质以及非水溶剂中的两个月浸泡期间，在宽pH范围（pH = 2–12）内可抵抗QD从TiO ₂表面脱离。这些发现可以帮助开发需要光敏单元长期稳定性的实用量子点敏化太阳能转换系统。

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Investigation of Interface Characteristics and Physisorption Mechanism in Quantum Dots/TiO2 Composite for Efficient and Sustainable Photoinduced Interfacial Electron Transfer

Owing to their superior stability compared to those of conventional molecular dyes, as well as their high UV–visible absorption capacity, which can be tuned to cover the majority of the solar spectrum through size adjustment, quantum dot (QD)/TiO₂ composites are being actively investigated as photosensitizing components for diverse solar energy conversion systems. However, the conversion efficiencies and durabilities of QD/TiO₂-based solar cells and photocatalytic systems are still inferior to those of conventional systems that employ organic/inorganic components as photosensitizers. This is because of the poor adsorption of QDs onto the TiO₂ surface, resulting in insufficient interfacial interactions between the two. The mechanism underlying QD adsorption on the TiO₂ surface and its relationship to the photosensitization process remain unclear. In this study, we established that the surface characteristics of the TiO₂ semiconductor and the QDs (i.e., surface defects of the metal oxide and the surface structure of the QD core) directly affect the QD adsorption capacity by TiO₂ and the interfacial interactions between the QDs and TiO₂, which relates to the photosensitization process from the photoexcited QDs to TiO₂ (QD* → TiO₂). The interfacial interaction between the QDs and TiO₂ is maximized when the shape/thickness-modulated triangular QDs are composited with defect-rich anatase TiO₂. Comprehensive investigations through photodynamic analyses and surface evaluation using X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and photocatalysis experiments collectively validate that tuning the surface properties of QDs and modulating the TiO₂ defect concentration can synergistically amplify the interfacial interaction between the QDs and TiO₂. This augmentation markedly improved the efficiency of photoinduced electron transfer from the photoexcited QDs to TiO₂, resulting in significantly increased photocatalytic activity of the QD/TiO₂ composite. This study provides the first in-depth characterization of the physical adhesion of QDs dispersed on a heterogeneous metal-oxide surface. Furthermore, the prepared QD/TiO₂ composite exhibits exceptional adsorption stability, resisting QD detachment from the TiO₂ surface over a wide pH range (pH = 2–12) in aqueous media as well as in nonaqueous solvents during two months of immersion. These findings can aid the development of practical QD-sensitized solar energy conversion systems that require the long-term stability of the photosensitizing unit.

更新日期：2024-02-09

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