Organic semiconductor

About: Organic semiconductor is a research topic. Over the lifetime, 15905 publications have been published within this topic receiving 533881 citations.

Trap-assisted recombination in disordered organic semiconductors.

Abstract: The trap-assisted recombination of electrons and holes in organic semiconductors is investigated. The extracted capture coefficients of the trap-assisted recombination process are thermally activated with an identical activation energy as measured for the hole mobility μp. We demonstrate that the rate limiting step for this mechanism is the diffusion of free holes towards trapped electrons in their mutual Coulomb field, with the capture coefficient given by (q/e)μp. As a result, both the bimolecular and trap-assisted recombination processes in organic semiconductors are governed by the charge carrier mobilities, allowing predictive modeling of organic light-emitting diodes. © 2011 American Physical Society.

Effect of doping on the density-of-states distribution and carrier hopping in disordered organic semiconductors

Abstract: The effect of doping on the density-of-states (DOS) distribution and charge-carrier transport in a disordered hopping system is considered analytically. It is shown that doping such a system produces a random distribution of dopant ions, which Coulombically interact with carriers localized in intrinsic hopping sites. This interaction further increases the energy disorder and broadens the deep tail of the DOS distribution. Therefore, doping of a disordered organic semiconductor, on the one hand, increases the concentration of charge carriers and lifts up the Fermi level but, on the other hand, creates additional deep Coulombic traps of the opposite polarity. While the former effect facilitates conductivity, the latter strongly suppresses the carrier hopping rate. A model of hopping in a doped disordered organic semiconductor is suggested. It is shown that the doping efficiency strongly depends upon the energy disorder and external electric field.

Molecular field‐effect transistors using conducting polymer Langmuir–Blodgett films

Abstract: Thin‐film field‐effect transistors (FETs) have been prepared using poly(3‐hexylthiophene)/ arachidic acid and quinquethiophene/arachidic acid Langmuir–Blodgett (LB) films with thicknesses ranging from a monolayer to some ten monolayers. The effect of the number of layers on the mobility and conductivity has been studied. This is to our knowledge the first demonstration of a LB FET utilizing organic semiconductors as the active material.