Details

Autor(en) / Beteiligte

• Dimitrov, Stoichko D
• Wheeler, Scot
• Niedzialek, Dorota
• Schroeder, Bob C
• Utzat, Hendrik
• Frost, Jarvist M
• Yao, Jizhong
• Gillett, Alexander
• Tuladhar, Pabitra S
• McCulloch, Iain
• Nelson, Jenny
• Durrant, James R

Titel

Polaron pair mediated triplet generation in polymer/fullerene blends

Ist Teil von

• Nature communications, 2015-03, Vol.6 (1), p.6501-6501, Article 6501

Ort / Verlag

England: Nature Publishing Group

Erscheinungsjahr

2015

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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.