Doping Induced Transition from Space-Charge-Limited to Ohmic Conduction in P3HT-PMMA

Mandal, S and Menon, R (2023) Doping Induced Transition from Space-Charge-Limited to Ohmic Conduction in P3HT-PMMA. In: Journal of Electronic Materials, 52 (11). 7645 -7651.

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Abstract

The charge transport mechanisms in poly(3-hexylthiophene)-poly(methyl methacrylate) [P3HT-PMMA] blends are investigated in terms of current density–voltage (J–V) characteristics and impedance spectroscopy studies. In the undoped sample, the J–V characteristics show two different transport mechanisms for low-voltage (ohmic) and higher-voltage (space-charge-limited) regions. However, after doping, the ohmic transport dominates over space-charge-limited conduction, as confirmed by J–V and Nyquist plot analysis. The resistive and capacitive contributions, relaxation time, and effective capacitance (C eff) values are calculated from fit parameters of an equivalent circuit model consisting of one resistor (R) and constant phase element (CPE) in parallel. The resistance and C eff values of the doped sample are decreased by a factor of 421 and 21.73, respectively. The relaxation time constant (τ) in the undoped sample is 1.75 μs, and it decreases to 19.7 ns in the doped sample. In the undoped sample, the difference in the value of τ, from low bias voltage (ohmic) to high bias voltage (space charge), shows the role of injected carriers, whereas τ remains unchanged in the doped sample. © 2023, The Minerals, Metals & Materials Society.

Item Type:	Journal Article
Publication:	Journal of Electronic Materials
Publisher:	Springer
Additional Information:	The copyright for this article belongs to the Springer.
Keywords:	Bias voltage; Capacitance; Carrier transport; Equivalent circuits; Esters; Relaxation time, Doped sample; Impedance spectroscopy; J-V characteristics; Nyquist plots; Poly (3-hexylthiophene); Poly(3-hexylthiophene); Poly(methyl methacrylate); Poly-methyl methacrylates; Space-charge limited, Electric space charge
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Oct 2023 07:45
Last Modified:	28 Oct 2023 07:45
URI:	https://eprints.iisc.ac.in/id/eprint/83150

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