高迁移率聚合物半导体材料最新进展

自20世纪80年代以来,聚合物半导体材料及其薄膜场效应晶体管器件(OFETs)已取得系列突破性进展.目前,已有数百种聚合物半导体材料被成功应用于OFETs中,空穴迁移率值最高已达36.3 cm~2·V~(-1)·s~(-1),可与有机小分子半导体材料甚至可同无定形硅相媲美.综述了近年来国内外高迁移率聚合物半导体的最新进展.分类对比总结和评述了空穴传输型(p-型)、电子传输型(n-型)和双极传输型聚合物半导体材料,并对聚合物半导体材料分子设计思路、薄膜OFETs器件制备及其性能参数进行了重点阐述.同时,总结了聚合物半导体材料的分子结构、聚集态结构与OFETs器件性能之间的内在关系,为今后设计与合成综合性能优异的聚合物半导体材料提供一定理论指导.     

高性能双极性聚合物半导体材料与晶体管器件

有机聚合物半导体材料与晶体管器件是融合了化学、材料、半导体以及微电子等学科的前沿交叉研究方向.聚合物半导体材料分子是该领域研究的重要内容,其中双极性聚合物分子半导体材料,兼具了电子和空穴的双重载流子输运能力而受到学术界的广泛关注.本文总结了双极性聚合物半导体材料与器件的研究进展,重点介绍了我们在D-A型双极性聚合物分子半导体材料设计、加工技术与器件制备以及功能应用方面的研究工作,并论述了双极性聚合物分子半导体材料与器件研究过程中存在的科学问题及发展方向.     

高性能的n-型和双极性有机小分子场效应晶体管材料

作为有机场效应晶体管的关键组成部分,有机半导体材料直接决定了器件的性能和稳定性。相比于p-型有机半导体材料,n-型和双极性有机半导体材料在迁移率和稳定性等方面则显著滞后。因此,n-型和双极性小分子有机半导体材料的设计与合成已成为高性能OFETs的学术研究的焦点。这篇综述重点突出了近十年报道的具有较好性能的n-型和双极性小分子有机半导体材料,并且对其结构和性能的关系进行了归纳,旨在对设计合成高性能、空气稳定的n-型和双极性有机小分子半导体材料提供一些指导帮助。     

溶液法大面积制备有机小分子场效应晶体管

作为柔性电子器件的基本构筑元件,有机场效应晶体管(OFETs)近年来受到深入研究并在高性能材料研发和器件多功能应用等方面取得了长足的进展。溶液加工技术以其温和的操作条件和灵活多样的工艺流程,成为实现高性能有机场效应晶体管器件低成本、大面积制备的优良选择。与聚合物相比,小分子有机半导体材料具有较高的固态堆积有序度及紧密程度和材料纯度,更易加工出性能优良的器件。然而小分子材料的成膜性较差,溶液加工潜能欠佳。如何通过不同的溶液加工技术制备取向均一的大面积连续小分子半导体薄膜,进而构筑高性能大面积器件阵列,成为了领域内的研究重点。本文概述了近年来可溶液加工且性能优良的小分子有机半导体材料研究进展,并依据工艺特点,分别介绍了溶液滴注、弯液面引导涂布和打印这三类可实现大面积制备的溶液加工技术,最后对溶液法大面积制备有机小分子场效应晶体管领域的发展前景进行了展望。     

有机场效应晶体管中给体-受体共聚物材料研究进展

自20世纪80年代至今,有机场效应晶体管(Organic field-effect transistor,OFET)的研究已经取得了很大的发展,目前可用于场效应晶体管的有机半导体材料已达数百种.经过30年的发展,有机场效应晶体管的迁移率从10-6~10-5cm2?V-1?s-1提高到12 cm2?V-1?s-1,增长了6个数量级,其性能已经超过了无定形性硅场效应晶体管(0.1~1 cm2?V-1?s-1).值得指出的是,目前该类高性能的材料几乎都是基于给体-受体(Donor-Acceptor,简称D-A)的共轭聚合物,它也被誉为第三代半导体材料.本文综述了近年来国内外D-A共聚物半导体材料的研究状况,对空穴传输型、双极传输型和电子传输型的D-A共聚物半导体材料进行了分类总结和评述,并对其设计思路,器件制备及性能做了详细介绍,总结了材料的化学结构与器件性能间的基本规律,为今后应用于有机场效应晶体管的给体-受体共聚物半导体材料提供设计思路.     

共轭聚合物材料的有序化,结晶化及器件应用研究

聚合物半导体材料因其可溶液加工的特点在构筑大面积、价廉、柔性有机器件方面引起了人们的广泛兴趣.但是,通常情况下,器件中聚合物半导体薄膜都是通过旋涂方式制备,该薄膜中分子的有序性差而且存在大量的晶界和缺陷,这不利于聚合物半导体材料本征性能的合理评价和高性能聚合物光电器件的制备.因此,如何制备高取向聚合物薄膜一直是该领域研...     

共轭聚合物微纳晶的制备与表征及其在场效应晶体管器件中的应用

导电聚合物是20世纪70年代发展起来的一个新兴研究领域,因其在有机光电子学中诱人的应用前景备受关注.但是,目前大部分的聚合物光电器件都是基于薄膜构筑的,大量的缺陷及无规的分子排列不利于我们对材料本征性能的评估及高性能光电器件的构筑.有机单晶具有分子长程有序、低缺陷和无晶界等优点,是用来解决这些问题的最佳选择,但是高质量聚合物单晶的获得一直都是一个挑战性的问题.本文综述了目前有关共轭聚合物微纳晶的制备、表征及其在场效应晶体管器件应用中的研究进展,并对共轭聚合物微纳晶材料与器件的发展前景和面临的一些问题做了简要的讨论.     

含醌式结构共轭聚合物的研究进展

共轭聚合物由于其优异的溶液加工特性和良好的机械性能,近些年来受到了学术界和工业界的广泛关注.将π电子离域性好、刚性强以及LUMO能级低的醌式单元引入共轭主链是构建高性能聚合物半导体材料的潜在方法.然而,如何将醌式结构引入聚合物体系具有一定的挑战.本专论总结了近年来含醌式结构共轭聚合物的研究进展,按照醌式单体的结构分类,介绍了醌式单体的设计与合成,以及含醌式结构共轭聚合物在不同光电器件中的应用,并论述了该领域研究过程中存在的问题和未来发展方向,以期为高性能聚合物半导体材料的开发提供借鉴和指导.     

有机场效应晶体管应用于化学及生物传感的研究进展

有机场效应晶体管(OFETs)是以有机半导体材料作为有源层的晶体管器件。和传统的无机半导体器件相比,由于其具有成本低、易加工、柔性好和生物相容性而被人们广泛研究,在多种化学和生物传感器领域具有潜在而广泛的应用前景。本文简单介绍了OFETs的结构和工作原理,总结了近几年来OFETs在化学及生物传感方面的研究进展,最后对OFETs的发展方向做了归纳和展望。     

酰胺与酰亚胺类n型有机半导体材料的研究进展

有机半导体材料具有来源丰富、化学结构可裁剪、柔韧性较高、器件制备温度低和塑料衬底兼容性好等优点, 极大地拓展了电子器件的功能与应用. 然而, 电子传输型(n型)有机半导体在分子多样性、载流子迁移率和空气稳定性方面远远落后于空穴传输型(p型)半导体, 从而阻碍了双极晶体管、p-n结和有机互补电路的发展. 酰胺或酰亚胺功能化能显著提高有机材料的电子亲和势, 是构建高性能n型有机半导体的重要策略. 本综述总结了近年来萘二酰亚胺类、苝二酰亚胺类、吡咯并吡咯二酮类、异靛蓝类和其他酰胺/酰亚胺类小分子和聚合物n型有机半导体材料的研究进展, 从分子设计角度出发, 深入讨论了分子结构如何改变分子前线轨道能级、分子间相互作用力、聚集态结构、器件稳定性和电学性能, 最后对其未来的发展方向和面临的挑战进行了展望.     

基于氟代异靛蓝并[7,6-g]异靛蓝的共轭聚合物的合成及其半导体性质

采用Stille缩聚,合成了3个异靛蓝并[7,6-g]异靛蓝(DIID)和乙烯单元交替排列的共轭聚合物P0F、P2F和P4F,三者在DIID单元中分别含0、2和4个氟原子(F).3个聚合物均具有良好的平面性,前线分子轨道几乎在整个共轭骨架上离域.它们均具有宽的吸收光谱,吸收范围在400~1000 nm,光学带隙约为1.25 eV;随着氟原子数目的增加,聚合物的最高占有分子轨道(HOMO)和最低空分子轨道(LUMO)能级依次下降0.1~0.2 eV.以这3个聚合物作为活性层,制备了顶栅-底接触型有机场效应晶体管器件,随着氟原子数目的增加,聚合物的传输性质由双极传输变为n型传输.P0F和P2F是双极传输型聚合物,空穴迁移率(μ_h)分别达到0.11和0.30 cm~2 V~(-1) s~(-1),电子迁移率(me)分别达到0.22和1.19 cm~2 V~(-1) s~(-1).P4F是n型聚合物,me达到0.18 cm~2 V~(-1) s~(-1).     

含硒杂环萘二酰亚胺衍生物的合成及其场效应性能研究

萘二酰亚胺(NDI)类化合物由于其较好的平面性和较强的接受电子能力,被广泛应用于有机场效应晶体管(OFETs)和有机太阳能电池中(OSCs)。然而,高迁移率的n型和双极性NDI类半导体材料较少。基于此,本文设计合成了核位硒杂环修饰的NDI衍生物,通过引入1,2-二硒苯和1,2-二硒萘基团,对其能级进行了有效的调控,获得了两个新型的窄带隙NDI衍生物。通过溶液旋涂法,制备了两种材料的底栅底接触场效应晶体管器件,二者在空气中都表现出n型半导体特性,退火温度为120℃时性能达到最优,分别为1×10~(-3)cm~2·V~(-1)·s~(-1)(4)和5×10~(-3)cm~2·V~(-1)·s~(-1)(5)。同时,通过原子力显微镜和X射线衍射对材料薄膜的退火过程进行了研究。     

Novel Thienyl DPP derivatives Functionalized with Terminal Electron-Acceptor Groups: Synthesis,Optical Properties and OFET Performance

Three novel diketopyrrolopyrrole (DPP) based small molecules have been synthesized and characterized in terms of their chemical-physical, electrochemical and electrical properties. All the molecules consist of a central DPP electron acceptor core symmetrically functionalized with donor bi-thienyl moieties and flanked in the terminal positions by three different auxiliary electron-acceptor groups. This kind of molecular structure, characterized by an alternation of electron acceptor and donor groups, was purposely designed to provide a significant absorption at the longer wavelengths of the visible spectrum: when analysed as thin films, in fact, the dyes absorb well over 800 nm and exhibit a narrow optical bandgap down to 1.28 eV. A detailed DFT analysis provides useful information on the electronic structure of the dyes and on the features of the main optical transitions. Organic field-effect transistors (OFETs) have been fabricated by depositing the DPP dyes as active layers from solution: the different end-functionalization of the dyes had an effect on the charge-transport properties with two of the dyes acting as n-type semiconductors (electron mobility up to 4.4 ⋅ 10⁻² cm²/V ⋅ s) and the third one as a p-type semiconductor (hole mobility up to 2.3 ⋅ 10⁻³ cm²/V ⋅ s). Interestingly, well-balanced ambipolar transistors were achieved by blending the most performant n-type and p-type dyes with hole and electron mobility in the order of 10⁻³ cm²/V ⋅ s     

Semiconducting Polymers Based on Simple Electron-Deficient Cyanated trans-1,3-Butadienes for Organic Field-Effect Transistors

Developing high-performance but low-cost n-type polymers remains a significant challenge in the commercialization of organic field-effect transistors (OFETs). To achieve this objective, it is essential to design the key electron-deficient units with simple structures and facile preparation processes, which can facilitate the production of low-cost n-type polymers. Herein, by sequentially introducing fluorine and cyano functionalities onto trans-1,3-butadiene, we developed a series of structurally simple but highly electron-deficient building blocks, namely 1,4-dicyano-butadiene ( CNDE ), 3-fluoro-1,4-dicyano-butadiene ( CNFDE ), and 2,3-difluoro-1,4-dicyano-butadiene ( CNDFDE ), featuring a highly coplanar backbone and deep-positioned lowest unoccupied molecular orbital (LUMO) energy levels (−3.03–4.33 eV), which render them highly attractive for developing n-type semiconducting polymers. Notably, all these electron-deficient units can be easily accessed by a two-step high-yield synthetic procedure from low-cost raw materials, thus rendering them highly promising candidates for commercial applications. Upon polymerization with diketopyrrolopyrrole ( DPP ), three copolymers were developed that demonstrated unipolar n-type transport characteristics in OFETs with the highest electron mobility of >1 cm² V⁻¹ s⁻¹. Hence, CNDE , CNFDE , and CNDFDE represent a class of novel, simple, and efficient electron-deficient units for constructing low-cost n-type polymers, thereby providing valuable insight for OFET applications.     

1-Imino nitroxide pyrene for high performance organic field-effect transistors with low operating voltage

Organic field-effect transistors (OFETs) fabricated with vapor-deposited films of 1-imino nitroxide pyrene show excellent p-type FET characteristics, with mobility up to 0.1 cm2 V-1 s-1 and an on/off ratio of nearly 5 x 104. Most remarkable feature of the FETs is their low operating voltage due to the low threshold voltage (about -0.6 V) and inverse subthreshold slope (about 540 mV decade-1).     

Perfluoropentacene: high-performance p-n junctions and complementary circuits with pentacene

We report the synthesis and characterization of perfluoropentacene as an n-type semiconductor for organic field-effect transistors (OFETs). Perfluoropentacene is a planar and crystalline material that adopts a herringbone structure as observed for pentacene. OFETs with perfluoropentacene were constructed using top-contact geometry, and an electron mobility of 0.11 cm2 V-1 s-1 was observed. Bipolar OFETs with perfluoropentacene and pentacene function at both negative and positive gate voltages. The improved p-n junctions are probably due to the similar d-spacings of both acenes. Complementary inverter circuits were fabricated, and the transfer characteristics exhibit a sharp inversion of the output signal with a high-voltage gain.     

Bithiophene-imide-based polymeric semiconductors for field-effect transistors: synthesis, structure-property correlations, charge carrier polarity, and device stability

Developing new high-mobility polymeric semiconductors with good processability and excellent device environmental stability is essential for organic electronics. We report the synthesis, characterization, manipulation of charge carrier polarity, and device air stability of a new series of bithiophene-imide (BTI)-based polymers for organic field-effect transistors (OFETs). By increasing the conjugation length of the donor comonomer unit from monothiophene (P1) to bithiophene (P2) to tetrathiophene (P3), the electron transport capacity decreases while the hole transport capacity increases. Compared to the BTI homopolymer P(BTimR) having an electron mobility of 10(-2) cm(2) V(-1) s(-1), copolymer P1 is ambipolar with balanced hole and electron mobilities of ～10(-4) cm(2) V(-1) s(-1), while P2 and P3 exhibit hole mobilities of ～10(-3) and ～10(-2) cm(2) V(-1) s(-1), respectively. The influence of P(BTimR) homopolymer M(n) on film morphology and device performance was also investigated. The high M(n) batch P(BTimR)-H affords more crystalline film microstructures; hence, 3× increased electron mobility (0.038 cm(2) V(-1) s(-1)) over the low M(n) one P(BTimR)-L (0.011 cm(2) V(-1) s(-1)). In a top-gate/bottom-contact OFET architecture, P(BTimR)-H achieves a high electron mobility of 0.14 cm(2) V(-1) s(-1), only slightly lower than that of state-of-the-art n-type polymer semiconductors. However, the high-lying P(BTimR)-H LUMO results in minimal electron transport on exposure to ambient. Copolymer P3 exhibits a hole mobility approaching 0.1 cm(2) V(-1) s(-1) in top-gate OFETs, comparable to or slightly lower than current state-of-the-art p-type polymer semiconductors (0.1-0.6 cm(2) V(-1) s(-1)). Although BTI building block incorporation does not enable air-stable n-type OFET performance for P(BTimR) or P1, it significantly increases the OFET air stability for p-type P2 and P3. Bottom-gate/top-contact and top-gate/bottom-contact P2 and P3 OFETs exhibit excellent stability in the ambient. Thus, P2 and P3 OFET hole mobilities are almost unchanged after 200 days under ambient, which is attributed to their low-lying HOMOs (>0.2 eV lower than that of P3HT), induced by the strong BTI electron-withdrawing capacity. Complementary inverters were fabricated by inkjet patterning of P(BTimR)-H (n-type) and P3b (p-type).     

Low-bandgap conjugated polymers based on benzodipyrrolidone with reliable unipolar electron mobility exceeding 1 cm~2 V~(-1) s~(-1)

The employment of an intrinsic quinoidal building block, benzodipyrrolidone(BDP), on constructing conjugated polymers(PBDP-2F and PBDP-2CN) with high electron mobility and unipolar transport characteristic in polyethylenimine ethoxylated(PEIE) modified organic field-effect transistors(OFETs) is reported. The intrinsic quinoidal characteristic and excellent coplanarity of BDP can lower the lowest unoccupied molecular orbital(LUMO) levels and improve ordered interchain packing of the resulting polymers in solid states, which are favorable for electron-injection and transport. By using PEIE as the interlayer to block the hole injection, unipolar n-type transport characteristics with high electron mobility of 0.58 and 1.01 cm~2 V~(-1) s~(-1) were achieved by the OFETs based on PBDP-2F and PBDP-2CN, respectively. More importantly, the extracted mobilities are highly reliable with the reliability factor of above 80%. To the best of our knowledge, PBDP-2CN is the very first quinoid-based conjugated polymer with reliable electron mobility exceeding 1 cm~2 V~(-1) s~(-1). This work represents a significant step in exploring intrinsic quinoidal CPs for application in n-channel OFETs and logic complementary circuits.     

非富勒烯聚合物太阳电池研究进展

综述了以p-型共轭聚合物为给体、n-型有机半导体为受体的非富勒烯聚合物太阳电池光伏材料最新研究进展,包括n-型共轭聚合物和可溶液加工小分子n-型有机半导体(n-OS)受体光伏材料,以及与之匹配的p-型共轭聚合物给体光伏材料.介绍的n-型共轭聚合物受体光伏材料包括基于苝酰亚胺(BDI)、萘酰亚胺(NDI)以及新型硼氮键连受体单元的D-A共聚物受体光伏材料,目前基于聚合物给体(J51)和聚合物受体(N2200)的全聚合物太阳电池的能量转换效率最高达到8.26%.n-OS小分子受体光伏材料包括基于BDI和NDI单元的有机分子、基于稠环中心给体单元的A-D-A型窄带隙有机小分子受体材料等.给体光伏材料包括基于齐聚噻吩和苯并二噻吩(BDT)给体单元的D-A共聚物,重点介绍与窄带隙A-D-A结构小分子受体吸收互补的、基于噻吩取代BDT单元的中间带隙二维共轭聚合物给体光伏材料.使用中间带隙的p-型共轭聚合物为给体、窄带隙A-D-A结构有机小分子为受体的非富勒烯聚合物太阳电池能量转换效率已经突破12%,展示了光明的前景.最后对非富勒烯聚合物太阳电池将来的发展进行了展望.     

Narrow band gap D–A copolymer of indacenodithiophene and diketopyrrolopyrrole with deep HOMO level: Synthesis and application in field‐effect transistors and polymer solar cells

A novel fused ladder alternating D–A copolymer, PIDT–DPP, with alkyl substituted indacenodithiophene (IDT) as donor unit and diketopyrrolopyrrole (DPP) as acceptor unit, was designed and synthesized by Pd‐catalyzed Stille‐coupling method. The copolymer showed good solubility and film‐forming ability combining with good thermal stability. PIDT–DPP exhibited a broad absorption band from 350 to 900 nm with an absorption peak centered at 735 nm. The optical band gap determined from the onset of absorption of the polymer film was 1.37 eV. The highest occupied molecular orbital level of the polymer is as deep as ?5.32 eV. The solution‐processed organic field‐effect transistor (OFETs) was fabricated with bottom gate/top contact geometry. The highest FET hole mobility of PIDT–DPP reached 0.065 cm² V^?1 s^?1 with an on/off ratio of 4.6 × 10⁵. This mobility is one of the highest values for narrow band gap conjugated polymers. The power conversion efficiency of the polymer solar cell based on the polymer as donor was 1.76% with a high open circuit voltage of 0.88 V. To the best of our knowledge, this is the first report on the photovoltaic properties of alkyl substituted IDT‐based polymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012