Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification.
Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification.
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DOI：
10.1038/ncomms15257
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发表时间：
2017-05-16
影响因子：
16.6
通讯作者：
Beard MC
中科院分区：
文献类型：
--
作者：
Kroupa DM;Vörös M;Brawand NP;McNichols BW;Miller EM;Gu J;Nozik AJ;Sellinger A;Galli G;Beard MC
半导体的带边位置在许多光电应用（如光伏、光电化学电池和发光二极管）中决定了它们的功能。在此我们表明，硫化铅（PbS）胶体半导体纳米晶体（特别是量子点）的带边位置可通过表面化学修饰在2.0电子伏特的范围内进行调节。我们通过开发简单、稳健且可扩展的溶液相配体交换方法实现了这种显著的调控，该方法用官能化的肉桂酸酯配体完全取代了原生配体，从而实现了定义明确、高度可调节的化学体系。通过结合实验和从头算模拟，我们确定了量子点表面化学与配体/量子点杂化体系带边位置之间的明确关系。我们发现，除了配体偶极子外，量子点间配体壳的相互交叉也对带边移动有贡献。我们期望我们所确定的关系和原理能够有助于指导未来针对多种光电应用的功能性有机/无机杂化纳米结构的优化。
半导体的带边位置决定了它们的光电性质。在此，作者建立了一种简单的配体交换策略来调节胶体硫化铅半导体量子点的带边位置，揭示了表面化学与带边位置之间的明确关系。
Band edge positions of semiconductors determine their functionality in many optoelectronic applications such as photovoltaics, photoelectrochemical cells and light emitting diodes. Here we show that band edge positions of lead sulfide (PbS) colloidal semiconductor nanocrystals, specifically quantum dots (QDs), can be tuned over 2.0 eV through surface chemistry modification. We achieved this remarkable control through the development of simple, robust and scalable solution-phase ligand exchange methods, which completely replace native ligands with functionalized cinnamate ligands, allowing for well-defined, highly tunable chemical systems. By combining experiments and ab initio simulations, we establish clear relationships between QD surface chemistry and the band edge positions of ligand/QD hybrid systems. We find that in addition to ligand dipole, inter-QD ligand shell inter-digitization contributes to the band edge shifts. We expect that our established relationships and principles can help guide future optimization of functional organic/inorganic hybrid nanostructures for diverse optoelectronic applications. The band edge positions of semiconductors decide their optoelectronic properties. Here, the authors establish a simple ligand exchange strategy to tune the band edge positions of colloidal PbS semiconductor quantum dots, revealing clear relationships between surface chemistry and band edge position.