Pentacene

About: Pentacene is a research topic. Over the lifetime, 5051 publications have been published within this topic receiving 161481 citations. The topic is also known as: 2,3:6,7-dibenzanthracene & benzo[b]naphthacene.

Hysteresis mechanism and reduction method in the bottom-contact pentacene thin-film transistors with cross-linked poly(vinyl alcohol) gate insulator

Abstract: The origin of the hysteresis phenomenon in bottom-contact pentacene organic thin-film transistors (OTFTs) with cross-linked poly(vinyl alcohol) (PVA) insulator is studied. From electrical measurements with various sweep ranges and two different sweep directions, the hysteresis effect is presumed to be caused by the electrons or holes that could be injected from the gate and trapped in the PVA bulk, rather than by the polarization or internally existing mobile ions. The assumption is confirmed by the clear reduction of hysteresis in OTFTs with a blocking oxide layer between gate and PVA insulator.

High-Performance Organic Light-Emitting Diodes Based on Dioxolane-Substituted Pentacene Derivatives†

Abstract: Organic light-emitting diodes (OLEDs) containing red-light-emitting dioxolane-substituted pentacene derivatives are fabricated and characterized. The OLEDs feature guest–host emitting layers consisting of either 6,14-bis(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]pentacene (TP-5) or 2,2,10,10-tetraethyl-6,14-bis(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]pentacene (EtTP-5) dispersed in tris(quinolin-8-olato) aluminum(III) (Alq3). High external electroluminescence (EL) quantum efficiency (ηEL = 3.3 %), not far from the theoretical limit, is observed for an OLED device based on a dilute EtTP-5:Alq3 emitting layer (0.25 mol % EtTP-5). The proposed EL mechanism is a combination of Forster energy transfer and direct electron–hole recombination on the guest pentacene molecules, as inferred by changes in the EL versus photoluminescence spectra and the positions of the highest occupied molecular orbital and lowest unoccupied molecular orbital gap of the guest within that of the host (estimated via cyclic voltammetry). Further evidence of charge trapping is provided by increased operational voltages at increased guest-molecule concentration.

Dynamics of Bimodal Growth in Pentacene Thin Films

Abstract: Previous studies have established that pentacene films deposited on silicon oxide consist of a substrate-induced "thin-film" phase, with the bulk phase of pentacene detected in thicker films only. We show that the bulk phase nucleates as early as the first monolayer, and continues to nucleate as film growth progresses, shadowing the growth of the thin-film phase. Moreover, we find that the transition between the "thin-film" and the bulk phase is not a continuous one, as observed in heteroepitaxial systems, but rather the two phases nucleate and grow independently.

Pentacene thin film transistors with a poly(methyl methacrylate) gate dielectric: Optimization of device performance

Abstract: The electrical characteristics of pentacene-based organic thin film transistors (OTFTs) using poly(methyl methacrylate) (PMMA) as the gate dielectric are reported. Uniform pinhole-free and crack-free films of PMMA could be obtained by spin coating, with a lower limit of thickness of about 150 nm. The effects of the insulator thickness and channel dimensions on the performance of the devices have been investigated. Leakage currents, which are present in many polymeric gate dielectrics, were reduced by patterning the pentacene active layer. The resulting devices exhibited minimal hysteresis in their output and transfer characteristics. Optimized OTFT structures possessed a field-effect mobility of 0.33 cm2 V−1 s−1, a threshold voltage of −4 V, a subthreshold slope of 1.5 V/decade, and an on/off current ratio of 1.2×106.