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Study of exciton-polaron interaction in pentacene field effect transistors using high sensitive photocurrent measurements
Haripriya Kesavan, Subhamoy Sahoo, Sanjoy Jena, Prashanth Kumar Manda, Amogh Kumar Baranwal, , Jayeeta Bhattacharyya,
Published in American Institute of Physics Inc.
2019
Volume: 126
   
Issue: 14
Abstract
Luminescence quenching in the presence of polarons is one of the major challenges in organic light emitting devices. In this work, exciton quenching in the presence of polarons is studied using phase sensitive photocurrent measurements on pentacene field effect transistors. The enhancement of conduction in the organic field effect transistors on light illumination is studied using photocurrent spectral response measurements and corresponding optical simulations. The photocurrent is shown to be governed by the polaron mobility and the exciton quenching efficiency, both of which depend on the polaron density in the channel. Two models are proposed on the exciton dynamics in the presence of gate induced polarons in the transistor channel. The first model simulates the steady-state exciton concentration profile in the presence of exciton-polaron interaction. The second one is a three-dimensional steady state exciton-polaron interaction model, which supports the findings from the first model. It is shown that the excitons quench by transferring its energy to polarons, thereby promoting the latter to high energy states in the density of states manifold. The polarons move in the higher energy states with greater microscopic mobility before thermalizing, thereby leading to an enhancement of conduction. It is observed that for the present system, where charge carrier transport is by hopping, all polarons interact with excitons. This implies that for low mobility systems, the interaction is not limited to deep trapped polarons. © 2019 Author(s).
About the journal
JournalData powered by TypesetJournal of Applied Physics
PublisherData powered by TypesetAmerican Institute of Physics Inc.
ISSN00218979
Open AccessNo
Concepts (18)
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    Carrier transport
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    Excitons
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    Light
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    Light emission
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    Organic field effect transistors
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    Organic light emitting diodes (oled)
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    Photocurrents
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    Quenching
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    Transistors
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    Concentration profiles
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    LIGHT ILLUMINATION
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    LUMINESCENCE QUENCHING
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    ORGANIC LIGHT-EMITTING DEVICES
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    PENTACENE FIELD EFFECT TRANSISTORS
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    PHOTOCURRENT MEASUREMENT
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    PHOTOCURRENT SPECTRAL RESPONSE
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    TRANSISTOR CHANNELS
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    Polarons