Polaron pair mediated triplet generation in polymer/fullerene blends

被引：80

作者：

Dimitrov, Stoichko D. ^{[1
]}

Wheeler, Scot ^{[1
]}

Niedzialek, Dorota ^{[2
]}

Schroeder, Bob C. ^{[1
]}

Utzat, Hendrik ^{[1
]}

Frost, Jarvist M. ^{[2
]}

Yao, Jizhong ^{[2
]}

Gillett, Alexander ^{[1
]}

Tuladhar, Pabitra S. ^{[1
]}

McCulloch, Iain ^{[1
,3
]}

Nelson, Jenny ^{[2
]}

Durrant, James R. ^{[1
]}

机构：

[1] Univ London Imperial Coll Sci Technol & Med, Ctr Plast Elect, Dept Chem, London SW7 2AZ, England

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

[3] King Abdullah Univ Sci & Technol, SPERC, Phys Sci & Engn Div, Thuwal 239556900, Saudi Arabia

来源：

NATURE COMMUNICATIONS | 2015年 / 6卷

基金：

英国工程与自然科学研究理事会;

关键词：

CHARGE-TRANSFER EXCITONS; GEMINATE RECOMBINATION; ELECTRON-TRANSFER; SOLAR-CELLS; PHOTOCURRENT COLLECTION; STATE; DISSOCIATION; ENERGY; NONGEMINATE; SPIN;

D O I：

10.1038/ncomms7501

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields.

引用

页数：8

共 50 条

[1] LOCALLY EXCITED TRIPLET-STATE PRODUCTION FROM EXCITED CHARGE-TRANSFER COMPLEXES [J].