Title
Direct measurement of the triplet exciton diffusion length in organic semiconductors
Author
Mikhnenko, O.V.
Ruiter, R.
Blom, P.W.M.
Loi, M.A.
Publication year
2012
Abstract
We present a new method to measure the triplet exciton diffusion length in organic semiconductors. N,N′-di-[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl)-4,4′-diamine (NPD) has been used as a model system. Triplet excitons are injected into a thin film of NPD by a phosphorescent thin film, which is optically excited and forms a sharp interface with the NPD layer. The penetration profile of the triplet excitons density is recorded by measuring the emission intensity of another phosphorescent material (detector), which is doped into the NPD film at variable distances from the injecting interface. From the obtained triplet penetration profile we extracted a triplet exciton diffusion length of 87±2.7nm. For excitation power densities >1mW/mm2 triplet-triplet annihilation processes can significantly limit the triplet penetration depth into organic semiconductor. The proposed sample structure can be further used to study excitonic spin degree of freedom. © 2012 American Physical Society.
Subject
Mechatronics, Mechanics & Materials
HOL - Holst
TS - Technical Sciences
High Tech Systems & Materials
Electronics
Industrial Innovation
Direct measurement
Emission intensity
Excitation power density
Model system
Penetration profiles
Phosphorescent material
Sample structure
Sharp interface
Spin degrees
Triplet excitons
Triplet-triplet annihilation
Diffusion
Interfaces (materials)
Naphthalene
Phosphorescence
Product development
Semiconducting organic compounds
Thin films
Excitons
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http://resolver.tudelft.nl/uuid:97a13ce1-eb77-4299-9d5e-3e2ea6a3ab1d
TNO identifier
461328
ISSN
0031-9007
Source
Physical Review Letters, 108 (13)
Article number
137401
Document type
article