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首页> 外文期刊>Chemistry: A European journal >Tuning Hole and Electron Transfer from Photoexcited CdSe Quantum Dots to Phenol Derivatives: Effect of Electron-Donating and -Withdrawing Moieties
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Tuning Hole and Electron Transfer from Photoexcited CdSe Quantum Dots to Phenol Derivatives: Effect of Electron-Donating and -Withdrawing Moieties

机译：从光屏蔽CDSE量子点到苯酚衍生物的调谐孔和电子转移：电子捐赠和绘制部分的影响

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摘要

Charge-transfer processes from photoexcited CdSe quantum dots (QDs) to phenol derivatives with electrondonating (4-methoxy) and -withdrawing (4-nitro) moieties have been demonstrated by using steady-state and timeresolved emission and femtosecond transient absorption spectroscopy. Steady-state and time-resolved emission studies suggest that in the presence of both 4-nitrophenol (4NP) and 4-methoxyphenol (4MP) CdSe QDs luminescence is quenched. Stern–Volmer analysis suggests both static and dynamic mechanisms are active for both the QD/phenol composites. Cyclic voltammetric analysis recommends that photoexcited CdSe QDs can donate electrons to 4NP and holes to 4MP. To reconfirm both electron- and hole-transfer mechanisms, CdSe/CdS quasi-type II and CdSe/CdTe type II core–shell nanocrystals were synthesized and photoluminescence quenching was monitored in the absence and presence of both 4NP and 4MP, for which hole and electron transfer were systematically restricted. Results suggest that indeed electron and hole transfer take place from photoexcited CdSe to 4NP and 4MP, respectively. To monitor the charge-transfer dynamics in both systems on an early timescale, femtosecond transient absorption spectroscopic techniques have been employed. Electron and hole transfer and charge-recombination dynamics are discussed and the effect of electron-donating and -withdrawing groups has been demonstrated.
机译：通过使用稳态和间歇发射和飞秒瞬态吸收光谱，已经证明了通过使用稳态和分子溶解的发射和飞秒和飞秒（4-甲氧基）和-WithDrawing（4-硝基）部分的苯酚衍生物的电荷转移过程。稳态和时间分辨的排放研究表明，在4-硝基苯酚（4NP）和4-甲氧基苯酚（4MP）CdSe QDS发光的情况下，淬火。 Stern-Volmer分析表明静态和动态机制对于QD /酚复合材料都是有效的。循环伏安分析建议光透明的Cdse QDS可以将电子捐赠给4NP和孔至4MP。为了再次测试电子和空穴转移机制，合成CDSE / CDS准型II和CDSE / CDTE II核 - 壳纳米晶体，在没有和存在4NP和4MP的情况下监测光致发光猝灭，其中孔和电子转移系统地限制。结果表明，实际上是电子和空穴传递分别从光屏蔽CDSE到4NP和4MP发生。为了在早期时间尺度上监控两个系统中的电荷传递动力学，采用了飞秒瞬态吸收光谱技术。讨论了电子和空穴传递和电荷重组动力学，并证明了电子捐赠和绘制组的效果。

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