表面陷阱态(STSs)的存在是影响量子点(QDs)电子和光学性质的关键因素之一,然而,STS如何影响量子点的确切机制尚不清楚。在这里，我们使用飞秒瞬态吸收光谱法证明了STS对CdSeQD中电子转移和从CdSe到表面受体的三重态-三重态能量转移（TTET）的影响。三种类型的胶体CdSe量子点，每个都含有不同程度的STS，如光致发光和X射线光电子能谱所证明的，被雇用。时间分辨发射和瞬态吸收光谱表明，STS可以有效地抑制带边发射，导致量子点中光电子的寿命从17.1ns显著降低到4.9ns。此外，对TTET过程的研究表明，STS可以抑制三重态激子的产生，有效地抑制带边发射，导致从CdSeQD到表面受体的TTET显着减少。这项工作为STS在塑造量子点光电特性方面的影响提供了证据，使其成为在涉及电子和能量转移的各种基于量子点的光电应用中理解和操纵STS的有价值的参考点。
The presence of surface trap states (STSs) is one of the key factors to affect the electronic and optical properties of quantum dots (QDs), however, the exact mechanism of how STSs influence QDs remains unclear. Herein, we demonstrated the impact of STSs on electron transfer in CdSe QDs and triplet-triplet energy transfer (TTET) from CdSe to surface acceptor using femtosecond transient absorption spectroscopy. Three types of colloidal CdSe QDs, each containing various degrees of STSs as evidenced by photoluminescence and X-ray photoelectron spectroscopy, were employed. Time-resolved emission and transient absorption spectra revealed that STSs can suppress band-edge emission effectively, resulting in a remarkable decrease in the lifetime of photoelectrons in QDs from 17.1 ns to 4.9 ns. Moreover, the investigation of TTET process revealed that STSs can suppress the generation of triplet exciton and effectively inhibit band-edge emission, leading to a significant decrease in TTET from CdSe QDs to the surface acceptor. This work presented evidence for STSs influence in shaping the optoelectronic properties of QDs, making it a valuable point of reference for understanding and manipulating STSs in diverse QDs-based optoelectronic applications involving electron and energy transfer.
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