Premium
Low‐Temperature Behaviour of Charge Transfer Excitons in Narrow‐Bandgap Polymer‐Based Bulk Heterojunctions
Author(s) -
Jarzab Dorota,
Cordella Fabrizio,
Gao Jio,
Scharber Markus,
Egelhaaf HansJoachim,
Loi Maria Antonietta
Publication year - 2011
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201100083
Subject(s) - exciton , photoluminescence , materials science , heterojunction , singlet state , charge (physics) , band gap , biexciton , diffusion , chemical physics , condensed matter physics , optoelectronics , molecular physics , atomic physics , physics , excited state , thermodynamics , quantum mechanics
Photoluminescence studies of the charge transfer exciton emission from a narrow‐bandgap polymer‐based bulk heterojunction are reported. The quantum yield of this emission is as high as 0.03%. Low temperature measurements reveal that while the dynamics of the singlet exciton is slower at low temperature, the dynamics of the charge transfer exciton emission is temperature independent. This behavior rules out any diffusion process of the charge transfer excitons and energy transfer from these interfacial states toward lower lying states. Photoluminescence measurements performed on the device under bias show a reduction (but not the total suppression) of the charge transfer exciton recombination. Finally, based on the low temperature results the role of the charge transfer excitons and the possible pathways to populate them are identified.