Entropically Driven Photochemical Upconversion

被引：86

作者：

Cheng, Yuen Yap ^{[1
]}

Fueckel, Burkhard ^{[1
]}

Khoury, Tony ^{[1
]}

Clady, Raphael G. C. R. ^{[1
]}

Ekins-Daukes, N. J. ^{[2
,3
]}

Crossley, Maxwell J. ^{[1
]}

Schmidt, Timothy W. ^{[1
]}

机构：

[1] Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia

[2] Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2AZ, England

[3] Univ London Imperial Coll Sci Technol & Med, Grantham Inst Climate Change, London SW7 2AZ, England

来源：

JOURNAL OF PHYSICAL CHEMISTRY A | 2011年 / 115卷 / 06期

基金：

澳大利亚研究理事会;

关键词：

TRIPLET-TRIPLET ANNIHILATION; STOKES DELAYED FLUORESCENCE; ENERGY-TRANSFER PROCESSES; TO-BLUE; GENERATION; CHROMOPHORES; EXCITATION; DYNAMICS; LIGHT; STATE;

D O I：

10.1021/jp108839g

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Conventional photochemical upconversion (UC) through homogeneous triplet triplet annihilation (TTA) is subject to several enthalpic losses that limit the UC margin. Here, we address one of these losses: the triplet energy transfer (TET) from the sensitizer to the emitter molecules. Usually, the triplet energy level of the emitter is set below that of the sensitizer. In our system, the triplet energy level of the emitter exceeds that of the sensitizer by similar to 600 cm(-1). Choosing suitable concentrations for the sensitizer and emitter molecules, we can exploit entropy as a driving force for the migration of triplet excitation from the sensitizer to the emitter manifolds. Thereby we obtain a new record for the peak-to-peak TTA-UC energy margin of 0.94 eV. A modified Stern-Volmer analysis yields a TET rate constant of 2.0 x 10(7) M-1 s(-1). Despite being relatively inefficient, the upconverted fluorescence is easily visible to the naked eye with irradiation intensities as low as 2 W cm(-2).

引用

页码：1047 / 1053

页数：7

共 37 条

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[2]

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