Grega McKenna N, Gan Jianing, Noman Muhammad, Asbury John B
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
J Phys Chem Lett. 2024 Apr 18;15(15):3987-3995. doi: 10.1021/acs.jpclett.4c00529. Epub 2024 Apr 4.
The nanocrystal-ligand boundaries of colloidal quantum dots (QDs) mediate charge and energy transfer processes that underpin photochemical and photocatalytic transformations at their surfaces. We used time-resolved infrared spectroscopy combined with transient electronic spectroscopy to probe vibrational modes of the carboxylate anchoring groups of stearate ligands attached to cadmium selenide (CdSe) QDs that were optically excited in solid nanocrystal films. The vibrational frequencies of surface-bonded carboxylate groups revealed their interactions with surface-localized holes in the excited states of the QDs. We also observed transient and reversible photoinduced ligand detachment from CdSe nanocrystals within their excited state lifetime. By probing both surface charge distributions and ligand dynamics on QDs in their excited states, we open a pathway to explore how the nanocrystal-ligand boundary can be understood and controlled for the design of QD architectures that most effectively drive charge transfer processes in solar energy harvesting and photoredox catalysis applications.
胶体量子点（QDs）的纳米晶体-配体边界介导电荷和能量转移过程，这些过程是其表面光化学和光催化转化的基础。我们使用时间分辨红外光谱结合瞬态电子光谱，来探测附着在硒化镉（CdSe）量子点上的硬脂酸配体的羧酸盐锚定基团的振动模式，这些量子点在固体纳米晶体薄膜中受到光激发。表面键合羧酸盐基团的振动频率揭示了它们在量子点激发态下与表面局域空穴的相互作用。我们还观察到在激发态寿命内，CdSe纳米晶体发生了瞬态且可逆的光诱导配体脱离。通过探测激发态量子点的表面电荷分布和配体动力学，我们开辟了一条途径，以探索如何理解和控制纳米晶体-配体边界，从而设计出在太阳能收集和光氧化还原催化应用中最有效地驱动电荷转移过程的量子点结构。
