摘要
针对常规F?rster共振能量转移(FRET)体系中能量转移效率低的问题,合成了可见光吸收的Ⅰ型CIS@Zn S核-壳量子点作为能量供体,近红外方酸(SQ)染料作为能量受体,采用超声自组装的方式首次制备了光谱匹配、间距可调的高效FRET能量转移体系.超快/时间分辨光谱证明了CIS和SQ之间的FRET能量转移机制:CIS*+SQ→CIS+SQ*.荧光猝灭动力学数据显示,CIS@Zn S与SQ之间的能量转移对量子点的尺寸存在依赖性,由CIS@Zn S尺寸增加引起的荧光量子产率和供体-受体间距的增加使得体系的FRET能量转移效率(ηFRET)先增大后减小,并且在壳层反应时间为20min时体系的ηFRET值达到最佳值62.8%.该研究对于开发新型、高效、全谱响应的太阳能电池将具有一定的理论及实际应用价值.
In order to overcome the low energy transfer efficiency of the conventional FRET（F？rster resonance energy transfer） system, a novel spectra-matching and distance-controllable CIS@Zn S-SQ FRET assembly has been prepared via ultrasonic self-assembly method, by using the synthesized visible CIS@Zn S type I core-shell quantum dots as energy donor and the near infrared SQ dyes as acceptor. Through controllable synthesis of quantum dots, the absorption and fluorescence performance of FRET system were adjusted by the size of CIS@Zn S, while the distance of energy donor-acceptor and the non-valid charge recombination in the FRET system were controlled by the wide-band shell of quantum dots. The excitons transfer and recombination kinetics in CIS@Zn S-SQ assembly were investigated by the pump-probe femtosecond ultrafast transient absorption measurements, with which results in the FRET-type energy transfer mechanism： CIS＊＋SQ→CIS＋SQ＊ has been proven and a high energy transfer rate of about 5.0×1010 s-1 has been gained between CIS@Zn S and SQ. The excitons＇ lifetime and FRET energy transfer efficiency were calculated from the fluorescence decay kinetic curves tested by time-resolved fluorescence measurements. The results show that the energy transfer in CIS@Zn S-SQ depends on the size of CIS@Zn S quantum dots. As the size of CIS@Zn S（mainly refers to the Zn S shell thickness） increases from 2.1±0.4 nm to 2.9±0.4 nm, 4.1±0.3 nm, 5.4±0.5 nm and 7.2±0.5 nm, the fluorescence quantum yield of CIS@Zn S improves from 5.4% to 26%, 33%, 38% and 43.3% as well as the distance between CIS@Zn S and SQ（energy donor and acceptor） increases gradually, which makes the FRET energy transfer efficiency（ηFRET） first rise and then decline. As a result, an optimal ηFRETvalue of 62.8% was gained in the FRET assembly when the reaction time of Zn S shell was 20 min. This research will have a promising theoretical and practical value for the development of the panchromatic and high-efficiency solar cells.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2016年第4期330-334,共5页
Acta Chimica Sinica
基金
国家自然科学基金(No.51502085)
湖北省自然科学基金(No.2013CFB064)资助~~
关键词
Ⅰ型量子点
近红外染料
宽光谱响应
能量转移
激子猝灭
type Ⅰ quantum dots
near-infrared dye
wide spectral response
energy transfer
exciton quenching
