Transistor Characteristics of Charge-Transfer Complexes Observed across a Neutral–Ionic Transition

Abstract

For basic understanding of transistor properties of doped organic semiconductors, 3,3′,5,5′-tetramethylbenzidine charge-transfer complexes are investigated, which change from neutral to ionic by varying the acceptors. When going into the ionic state, the bulk conduction increases more rapidly than the mobility, but sufficiently thin devices exhibit transistor properties. The resulting ambipolar characteristics are analyzed in the linear regions at small drain voltages in analogy with graphene transistors. The model is further extended to include partial overlap of electron and hole transport regions. In the temperature dependence, the activation energy loses gate voltage dependence when the neutral–ionic transition takes place by 0.1–0.2 eV above the equal acceptor and donor levels; the difference comes from the typical trap (polaron) depth or the Madelung energy.

Tetramethylbenzidine-TetrafluoroTCNQ: A narrow-gap semiconducting salt with room temperature relaxor ferroelectric behavior

“…14) were measured and showed high source-drain currents (I D ) in FET measurements at low drain voltages with corresponding gate-leakage currents of at least two orders of magnitude smaller. No clear field-effect was observed in the applied voltage range, in contrast to what it has been recently reported by Uekusa et al [23] with a series of TMB Acceptor CT crystals and films. Crystal bulk conductivity is probably dominant in the measured current, and the contribution of a possible thin-gate induced transistor channel at the dielectric/semiconductor interface is not clearly detectable.…”

“…The T dependence of the conductance is reported for two samples in the top panels of Figure 3, and allows the extraction of the activation energy E a , which turns out to be 0.32 -0.33 eV, in agreement with Ref. [23].…”

Thin films of electron donor–acceptor complexes: characterisation of mixed-crystalline phases and implications for electrical doping

“…[9][10][11] The study presented here shows a crossing of the neutralionic boundary by chemical variation of donor and acceptor molecules. Furthermore, crossing this boundary is possible by chemical substitution 77,78 as well as pressure or temperature changes. 65,68 Chemical substitution is present for TCNNQ and F6TCNNQ molecules.…”

Facile Charge Transfer between Barbituric Acid and Chloranilic Acid over g-C3N4: Synthesis, Characterization and DFT Study

“…The charge transfer process (CT) has been extensively investigated in material science [1][2][3][4], biological systems [5,6], and crystal engineering [7,8]. The CT process is initiated between high electron donor molecules (Donors) and electron-deficient molecules (Acceptors) to form stable CT adducts [9,10].…”

“…The CT process is initiated by HB formation and proceeds through the proton transfer process (PT) [20][21][22]. Different organic acceptors efficiently act as proton donors, such as chloranilic acid (ChA) [13,20,21], 7,7,8,8-tetracyanoquinodimethane (TCNQ) [1], and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) [21]. The kinetics of the PT process play a key role in different biological systems [23][24][25] and electronic devices [26,27].…”