Differentiation between polaron-pair and triplet-exciton polaron spin-dependent mechanisms in organic light-emitting diodes by coherent spin beating

被引：63

作者：

Baker, W. J. ^{[1
]}

McCamey, D. R. ^{[1
,2
]}

van Schooten, K. J. ^{[1
]}

Lupton, J. M. ^{[1
,3
]}

Boehme, C. ^{[1
]}

机构：

[1] Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA

[2] Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia

[3] Univ Regensburg, Inst Expt & Angew Phys, Regensburg, Germany

来源：

PHYSICAL REVIEW B | 2011年 / 84卷 / 16期

基金：

澳大利亚研究理事会;

关键词：

PI-CONJUGATED POLYMERS; SEMICONDUCTORS; PHOTOGENERATION; RECOMBINATION; SINGLET; FILMS;

D O I：

10.1103/PhysRevB.84.165205

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Pulsed electrically detected magnetic resonance offers a unique avenue to distinguish between polaron-pair (PP) and triplet-exciton polaron (TEP) spin-dependent recombination, which control the conductivity and magnetoresistivity of organic semiconductors. Which of these two fundamental processes dominates depends on carrier balance: by injecting surplus electrons we show that both processes simultaneously impact the device conductivity. The two mechanisms are distinguished by the presence of a half-field resonance, indicative of TEP interactions, and transient spin beating, the signature of PPs. Coherent spin Rabi flopping in the half-field (triplet) channel is observed, demonstrating that the triplet exciton has an ensemble phase coherence time of at least 60 ns, offering insight into the effect of carrier correlations on spin dephasing.

引用

页数：7