物理学报Issue(10)：1-8,8.DOI:10.7498/aps.64.108201
CdTe量子点与罗丹明B水溶液体系下的双光子激发荧光共振能量转移∗
Fluorescence resonance energy transfer in a aqueous system of CdTe quantum dots and Rho damine B with two-photon excitation
摘要
Abstract
Fluorescence resonance energy transfer (FRET) is non-radiation energy transfer that occurs between a donor (D) molecule in an excited state and an acceptor (A) molecule in a ground state by dipole-dipole interactions. The efficiency of FRET is dependent on the extent of spectral overlap between the donor photoluminescence peak and the absorption spectrum of acceptor, the quantum yield of the donor, and the distance between the donor and acceptor molecules. Cur-rently, FRET is commonly used for determining the metal ion, analyzing the protein, biological molecular fluorescence probe, etc. In this study, the FRET between CdTe quantum dots (QDs) with different sizes and Rhodamine B (RhB) in aqueous solution is investigated by using the time-resolved fluorescence test system under two-photon excitation. In this two-photon FRET aqueous system, QD is used as donor while RhB as acceptor. The time resolved two-photon photo-luminescence and fluorescence lifetime measurements are performed for analyzing the two-photon-excited luminescence by using a titanium sapphire femtosecond laser with a wavelength of 800 nm, pulse width of 130 fs, repetition frequency of 76 MHz, with the power fixed at 500 mW. The fluorescence spectrum is measured by fluorescence spectrometer and the fluorescence decay curves are recorded by single photon counter. Besides, the steady state photoluminescence is also studied with a JASCO FP-6500 Fluorescence Spectrometer. The result shows that with the increase of spectral overlap of the CdTe emission spectrum and the Rhodamine B absorption spectrum, the FRET efficiency of the QDs-RhB system becomes higher. Specifically, the fluorescence intensity of QDs decreases and the lifetime of QDs becomes shorter while RhB shows the opposite tendency. By means of the Förster theory of energy transfer, the spectral overlap integral J (λ), Foster radius R0 and the FRET efficiency E are calculated and the FRET characteristics of QD-RhB system is charac-terized. Theoretical analysis reveals that the physical source is the increase of the sample’s Forster radius. Moreover, the relationship between the ratio of acceptor/donor concentration and the FRET efficiency is investigated experimentally. When the ratio of acceptor/donor concentration increases, the lifetime of QDs turns shorter, and the FRET efficiency of the QDs-RhB system becomes higher. The two-photon excited FRET efficiency can reach 40.1%when the concentration of RhB is 3.0 × 10−5 mol·L−1. This study shows a brighter future in biological and optoelectronic applications.关键词
能量转移/多光子过程/光学材料/光学特性Key words
energy transfer/multiphoton processes/optical materials/optical properties引用本文复制引用
李牧野,李芳,魏来,何志聪,张俊佩,韩俊波,陆培祥..CdTe量子点与罗丹明B水溶液体系下的双光子激发荧光共振能量转移∗[J].物理学报,2015,(10):1-8,8.基金项目
国家自然科学基金(批准号:11204222)、湖北省自然科学基金(批准号:2013CFB316,2014CFB793)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant No.11204222), the Natural Science Foundation of Hubei Province, China (Grant Nos.2013CFB316,2014CFB793) （批准号:11204222）
