A diketopyrrolopyrrole‐based conjugated polymer, PDPP‐4FTVT, which exhibits ambipolar transport behavior in air with hole and electron mobilities up to 3.40 and 5.86 cm2 V−1 s−1, respectively, is ...synthesized via direct arylation polycondensation. Incorporation of F‐atoms in β‐positions of thiophene rings dramatically improves the efficiency of direct arylation polycondensation.
A heterojunction device which has good transport characteristics and low sensitivity is obtained through two kinds of organic molecules inert to NO2. Using the heterojunction device, constructing ...more‐sensitive double‐heterojunction devices can obtain better room‐temperature detection characteristics.
Abstract
Considerable efforts have been made to realize nanoscale diodes based on single molecules or molecular ensembles for implementing the concept of molecular electronics. However, so far, ...functional molecular diodes have only been demonstrated in the very low alternating current frequency regime, which is partially due to their extremely low conductance and the poor degree of device integration. Here, we report about fully integrated rectifiers with microtubular soft-contacts, which are based on a molecularly thin organic heterojunction and are able to convert alternating current with a frequency of up to 10 MHz. The unidirectional current behavior of our devices originates mainly from the intrinsically different surfaces of the bottom planar and top microtubular Au electrodes while the excellent high frequency response benefits from the charge accumulation in the phthalocyanine molecular heterojunction, which not only improves the charge injection but also increases the carrier density.
Herein, we report the synthesis and characterization of a series of 1benzothieno3,2-b1benzothiophene (BTBT)-based asymmetric conjugated molecules, that is, ...2-(5-alkylthiophen-2-yl)1benzothieno3,2-b1benzothiophene (BTBT-Tn, in which T and n represent thiophene and the number of carbons in the alkyl group, respectively). All of the molecules with n ≥ 4 show mesomorphism and display smectic A, smectic B (n = 4), or smectic E (n > 4) phases and then crystalline phases in succession upon cooling from the isotropic state. Alkyl chain length has a noticeable influence on the microstructures of vacuum-deposited films and therefore on the performance of the organic thin-film transistors (OTFTs). All molecules except for 2-(thiophen-2-yl)1benzothieno3,2-b1benzothiophene and 2-(5-ethylthiophen-2-yl)1benzothieno3,2-b1benzothiophene showed OTFT mobilities above 5 cm2 V–1 s–1. 2-(5-Hexylthiophen-2-yl)1benzothieno3,2-b1benzothiophene and 2-(5-heptylthiophen-2-yl)1benzothieno3,2-b1benzothiophene showed the greatest OTFT performance with reliable hole mobilities (μ) up to 10.5 cm2 V–1 s–1 because they formed highly ordered and homogeneous films with diminished grain boundaries.
Crystalline white organic light-emitting diodes (C-WOLEDs) are promising candidates for lighting and display applications. It is urgently necessary, however, to develop energy-saving and ...high-efficiency C-WOLEDs that have stable and powerful emission to meet commercial demands. Here, we report a crystalline host matrix (CHM) with embedded nanoaggregates (NA) structure for developing high-performance C-WOLEDs by employing a thermally activated delayed fluorescence (TADF) material and orange phosphorescent dopants (Phos.-D). The CHM-TADFNA-D WOLED exhibit a remarkable EQE of 12.8%, which is the highest performance WOLEDs based on crystalline materials. The device has a quick formation of excitons and a well-designed energy transfer process, and possesses a fast ramping of luminance and current density. Compared to recently reported high-performance WOLEDs based on amorphous material route, the C-WOLED achieves a low series-resistance Joule-heat loss ratio and an enhanced photon output, demonstrating its significant potential in developing the next-generation WOLEDs.
High-mobility thin film transistors of para-sexiphenyl (p-6P)/2,9-diphenyl-dinaphtho2,3-b:2′,3′-f-thieno3,2-b thiophene (2,9-DPh-DNTT) are demonstrated by employing copper hexadecafluorophthalocyanine ...(F16CuPc), cobalt (II) hexadecafluoro-phthalocyanine (F16CoPc) and molybdenum oxide (MoO3) as buffer layers. The highest field-effect mobility of 9.3 cm2/Vs is achieved by using the F16CoPc buffer layer, which is the highest reported mobility for polycrystalline 2,9-DPh-DNTT thin film transistors. The improvement of the device performance is due to reducing device contact resistance between metal electrodes and the organic semiconductor and improving the carrier injection. Based on the optimized results, we fabricated an OTFT array consisting of p-6P/2,9-DPh-DNTT OTFTs with F16CoPc as the buffer layer by photolithography. A high mobility of 2.7 cm2/Vs and a low VT of −2.3 V are achieved which proved that 2,9-DPh-DNTT is an excellent organic semiconductor in the field such as a large-area display and sensor matrix, etc.
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•High mobility values are obtained by employing different buffer layers in p-6P/2,9-DPh-DNTT OTFTs, and the maximum value of 9.3 cm2/Vs is achieved.•By investigating the contact resistance, the reason of the improvement of OTFT performance is revealed.•An average hole mobility of 2.7 cm2/Vs is obtained in the OTFT array processed by the photolithography technology.
An efficient organic solar cell is fabricated by the weak‐epitaxy‐growth method and the achieved power conversion efficiency is over 3% (see figure). A Single‐crystal‐like thin film improves the ...carrier mobility and reduces the electron–hole recombination. Deposition of a zinc phthalocyanine (ZnPc):C60 mixed layer at 100 °C results in a better interpenetrating interface and the device performance is improved further.
2,9-DPh-DNTT, an isomeric of diphenyl-dinaphtho2,3-b:2′,3′-f-thieno3,2-b thiophene (DPh-DNTTs), is an emerging candidate of high mobility organic semiconductor material. In this work, a high ...performance 2,9-DPh-DNTT organic thin-film transistor (OTFT) is fabricated by the method of weak epitaxy growth. The quality of 2,9-DPh-DNTT thin film was significantly improved when its epitaxial layer grows on an inducing layer of para-sexiphenyl (p-6P). Continuous large-area, highly ordered and terraced 2,9-DPh-DNTT polycrystalline thin films are obtained. The hole mobility of as-fabricated 2,9-DPh-DNTT thin-film transistor reaches up to 6.4 cm2 V−1s−1. This simple process of preparing high mobility 2,9-DPh-DNTT thin-film transistor supplies a facile route of large-area OTFT fabrication.
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•High quality 2,9-DPh-DNTT epitaxial thin film was prepared by weak epitaxy growth method.•The epitaxy relationship between 2,9-DPh-DNTT and p-6P was confirmed by the selected area electron diffraction.•OTFTs based on p-6P/2,9-DPh-DNTT with a high hole mobility up to 6.4 cm2−1s−1 were achieved.
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