Investigation of Fluorescence Emission from CdSe Nanorods in PMMA and P3HT/PMMA Films
Investigation of Fluorescence Emission from CdSe Nanorods in PMMA and P3HT/PMMA Films
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PMMA 和 P3HT/PMMA 薄膜中 CdSe 纳米棒的荧光发射研究
DOI：
10.1021/jp404585j
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Chikan, Viktor
中科院分区：
文献类型：
--
作者：
Sarkany, Lorinc;Wasylenko, Jenna M.;Roy, Santanu;Higgins, Daniel A.;Elles, Christopher G.;Chikan, Viktor
互补荧光显微镜和超快瞬态吸收光谱测量跨越从秒到飞秒的时间尺度范围，探测CdSe纳米棒/聚合物混合物中电荷载流子的界面动力学。总之，这些非常不同的技术提供了新的信息的起源和动力学的带边以下的发射从CdSe纳米棒在CdSe/PMMA和CdSe/P3 HT/PMMA膜[PMMA =聚（甲基丙烯酸甲酯）; P3 HT =聚（3-己基噻吩）]。低于CdSe纳米棒的能带边缘的发射与纳米颗粒/聚合物界面处的表面缺陷（陷阱）相关联，其中导带电子辐射地弛豫到带内缺陷位点。荧光显微镜实验同时监测单个纳米颗粒的陷阱发射和带边发射，并揭示这两个发射通道是不同的。两种发射状态之间的转换发生在超过200 ms的时间尺度上，并且总是涉及一个中间的黑暗状态，其中没有观察到发射。P3 HT的存在增加了相对带边发射强度，并降低了两种发射状态的荧光闪烁性（闪烁）。的超快瞬态吸收实验监测的受激发射带的演化低于CdSe带边以下的P3 HT激发。测量结果表明，超快的电子转移从光激发的P3 HT的CdSe纳米棒的仪器响应时间约为140 fs内，并确认，在这些稀释的共混物中的纳米棒和P3 HT之间有很强的耦合。对单独的CdSe纳米棒蚀刻实验的分析表明，陷阱态是通过在氯仿存在下从纳米棒的末端去除原子而形成的。在纳米粒子/聚合物界面的电荷捕获机制进行了讨论。
Complementary fluorescence microscopy and ultrafast transient absorption spectroscopy measurements spanning a range of time scales from seconds to femtoseconds probe the interfacial dynamics of charge carriers in CdSe nanorod/polymer blends. Together, these very different techniques provide new information about the origin and dynamics of below-band-edge emission from CdSe nanorods in CdSe/PMMA and CdSe/P3HT/PMMA films [PMMA = poly(methyl methacrylate); P3HT = poly(3-hexylthiophene)]. Emission below the band edge of the CdSe nanorods is associated with surface defects (traps) at the nanoparticle/polymer interface, where conduction band electrons radiatively relax to the intraband defect sites. The fluorescence microscopy experiments simultaneously monitor both the trap emission and the band edge emission from single nanoparticles, and reveal that the two emission channels are distinct. Transitions between the two emissive states occur on time scales longer than ∼20 ms, and always involve an intermediate dark state in which no emission is observed. The presence of P3HT increases the relative band edge emission intensity and reduces the fluorescence intermittency (blinking) of both emissive states. The ultrafast transient absorption experiments monitor the evolution of a stimulated emission band below the CdSe band edge following excitation of P3HT. The measurements reveal ultrafast electron transfer from photoexcited P3HT to the CdSe nanorods within the instrument response time of approximately 140 fs, and confirm that there is strong coupling between the nanorods and P3HT in these dilute blends. Analysis of separate CdSe nanorod etching experiments suggests that the trap states are formed by the removal of atoms from the ends of the nanorods in the presence of chloroform. Mechanisms for charge trapping at the nanoparticle/polymer interface are discussed.
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染料掺杂硅酸盐和聚合物薄膜中的微观不均匀性
DOI：
--
发表时间：
1998
期刊：
影响因子：
--
作者：
Hanming Wang;Angela M. Bardo;M. Collinson;D. Higgins
通讯作者：
D. Higgins
影响因子：
17.1
作者：
K. Knappenberger;Daryl B. Wong;W. Xu;A. Schwartzberg;A. Wolcott;J. Zhang;S. Leone
通讯作者：
K. Knappenberger;Daryl B. Wong;W. Xu;A. Schwartzberg;A. Wolcott;J. Zhang;S. Leone
影响因子：
3.3
作者：
Khanh Hoa Tran Ba;Everett, Thomas A.;Higgins, Daniel A.
通讯作者：
Higgins, Daniel A.
影响因子：
4.4
作者：
Kuno, M;Fromm, DP;Nesbitt, DJ
通讯作者：
Nesbitt, DJ
通过光学显微镜研究 CdSe 纳米棒 P3HT/PMMA 混合物中的电荷转移相互作用
影响因子：
3.7
作者：
Santanu Roy;A. Aguirre;D. Higgins;V. Chikán
通讯作者：
V. Chikán