| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1263623 | Organic Electronics | 2015 | 5 Pages |
•We study temperature-induced electrical properties between n- and p-type operations.•Temperature effects on hysteresis characteristics of ambipolar OTFTs were studied.•Ambipolar characteristics were largely affected by the opposite-signed carriers.•The DCRR process is an electric field-assisted thermal-activated procedure.•Electrons are hardly to release from opposite-signed carriers than that of holes.
The temperature-dependent electrical and charge transport characteristics of pentacene-based ambipolar thin-film transistors (TFTs) were investigated at temperatures ranging from 77 K to 300 K. At room temperature (RT), the pentacene-based TFTs exhibit balanced and high charge mobility with electron (μe) and hole (μh) mobilities, both at about 1.6 cm2/V s. However, at lower temperatures, higher switch-on voltage of n-channel operations, almost absent n-channel characteristics, and strong temperature dependence of μe indicated that electrons were more difficult to release from opposite-signed carriers than that of holes. We observed that μe and μh both followed an Arrhenius-type temperature dependence and exhibited two regimes with a transition temperature at approximately 210–230 K. At high temperatures, data were explained by a model in which charge transport was limited by a dual-carrier release and recombination process, which is an electric field-assisted thermal-activated procedure. At T < 210 K, the observed activation energy is in agreement with unipolar pentacene-based TFTs, suggesting a common multiple trapping and release process-dominated mechanism. Different temperature-induced characteristics between n- and p-channel operations are outlined, thereby providing important insights into the complexity of observing efficient electron transport in comparison with the hole of ambipolar TFTs.
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