溶剂沸点对聚(3-己基噻吩)薄膜内链结构与分子取向的影响

以聚(3-己基噻吩)(P3HT)为研究对象,借助荧光相关光谱、紫外-可见光谱和掠角红外光谱考察了溶剂性质对旋涂膜内P3HT的链结构与分子取向的影响。结果表明:溶液中P3HT的分子链构象受溶解度的影响,当P3HT溶解在溶解性好的良溶剂中时,链构象更伸展;固体薄膜内P3HT的物理结构却不受其在溶剂中溶解度大小的影响而具有沸点依赖性,溶解在高沸点溶剂中的P3HT旋涂后,薄膜内P3HT主链平面性与π-π相互作用均得到提高;此外,溶剂沸点的增加导致分子取向由"面朝上"方式转变为"边朝上"方式。     

氯仿改性聚（3-己基噻吩）有机电化学晶体管及其神经突触功能模仿

通过旋涂法制备了有机半导体聚（3-己基噻吩）（P3HT）薄膜，在二氯苯溶剂中引入氯仿对P3HT薄膜进行改性。以改性的P3HT薄膜作为沟道层，以离子凝胶作为电解质层制备了有机电化学晶体管（OECT）。通过原子力显微镜、紫外-可见光谱和拉曼光谱探究了氯仿改性对P3HT薄膜粗糙度和分子有序度的影响，采用半导体参数仪研究了氯仿改性对材料电学性能的影响。实验结果表明，氯仿改性降低了P3HT薄膜的粗糙度，提高了分子排列的有序度。氯仿改性后的OECT在-0.5 V和-1.0 V的电脉冲刺激下呈现显著的神经突触兴奋脉冲电流响应特性，相比于未改性的器件，电导调控幅值分别增加了约2倍和16倍，且延长了其保持特性。基于氯仿改性OECT的人工神经突触网络将MNIST手写数字识别准确率从73.6%提高至92.7%，有望在高性能神经形态计算方面发挥重要作用。     

一种基于聚噻吩-聚硒吩全共轭嵌段共聚物的合成及性质研究

全共轭刚性-刚性嵌段共聚物兼具嵌段共聚物的微相分离特性和共轭聚合物的光电性能，引起了人们越来越多的关注.基于此，我们利用格氏置换（GRIM）方法合成了全共轭刚性-刚性嵌段共聚物聚（3-己基硒吩）-b-聚（3-（6-羟基）-己基噻吩）（P3HS-b-P3HHT）.通过在噻吩段的烷基侧链末端引入羟基基团来丰富全共轭体系的溶液结构，并利用羟基的热交联特性提高聚噻吩均聚物的薄膜场效应晶体管的热稳定性.一方面，通过溶剂共混（氯仿/吡啶和甲醇/吡啶混合溶剂），调控P3HS-b-P3HHT分子在混合溶剂中的刚性-刚性相互作用，使P3HS-b-P3HHT在混合溶剂中自组装形成不同的纳米结构，如纳米带、纳米纤维和纳米微球等.另一方面，将P3HS-b-P3HHT和聚（3-己基噻吩）（P3HT）共混，利用羟基之间的热交联，使P3HS-b-P3HHT/P3HT共混薄膜在薄膜场效应晶体管中表现出较好的热稳定性.     

Cu2+对不同相形态中聚3-己基噻吩光学性质的影响

用紫外-可见吸收光谱和荧光光谱方法研究了Cu2+分别与稀溶液、分散液和薄膜三种体系中的聚3-己基噻吩(P3HT)的相互作用. 结果表明, P3HT的相形态对其相互作用有重要影响. 在四氢呋喃的稀溶液中, P3HT与Cu2+的溶剂化程度都很高, 它们之间几乎不存在化学作用; 在分散液中, P3HT形成聚集的颗粒, Cu2+的加入产生较弱的氧化掺杂, Cu2+部分进入到分散颗粒中; 在P3HT的薄膜中, Cu2+使链的共轭长度变短, 引起光吸收蓝移.     

硅纳米线和聚3-十二烷基噻吩混合薄膜在场效应晶体管中的应用研究

为了提高聚3-十二烷基噻吩的场效应迁移率, 将硅纳米线混入聚3-十二烷基噻吩的溶液中制成薄膜. 退火后的聚3-十二烷基噻吩能够自组装成有序的微晶结构, 有利于电子传输. 聚3-十二烷基噻吩薄膜在场效应晶体管中能够获得0.015 cm²·V^-1·s^-1的迁移率, 而混合薄膜能够获得高达0.68 cm²·V^-1·s^-1的迁移率. 这是因为硅纳米线优异的电子传输性能使得电子通过硅纳米线就像通过快速通道一样, 从而能够缩短电子在场效应晶体管中的传输时间, 提高传输速度. 此外, 使用离子胶作为介电层也能够提升场效应晶体管的性能, 混合薄膜能够获得高达6.2 cm²·V^-1·s^-1的迁移率.     

基底温度对刮涂制备的P3HT:PCBM薄膜形貌和光伏电池性能的影响

研究了刮涂制备P3HT:PCBM(P3HT:聚3-己基噻吩,PCBM:[6,6]-苯基-C61-丁酸甲酯)活性层的过程中,基底温度对P3HT:PCBM活性层薄膜性质和电池性能的影响.结果表明,提高基底温度在缩短薄膜干燥时间的同时,抑制了PCBM相的大尺度聚集,并改善了P3HT:PCBM薄膜中P3HT在(100)方向上的结晶程度,但降低了π-π共轭方向上的有序度.制备的光伏电池经过进一步退火处理后可形成良好的互穿网络结构,能量转换效率可达3.93％.     

外场对聚(3-己基噻吩)溶液结晶行为的影响

以聚(3-己基噻吩)(P3HT)为研究对象,借助紫外-可见光谱与原子力显微镜,详细考察了旋转剪切场、紫外光照射、超声处理3种外场对P3HT/混合溶剂(CHCl3-CH2Cl2)体系结晶行为的影响,此外,还研究了P3HT溶液结晶的"记忆效应"。研究表明:旋转场能够显著提高P3HT的结晶度,而紫外光照射和超声处理易使溶液中分子链的活动性增加,对结晶性的影响不显著;施加外场并没有改变溶液中纳米线的聚集形式,仍为H聚集;P3HT溶液的初始态不同,其结晶过程中的晶体微结构及形貌也会发生变化。     

含有酰亚胺结构单元的氮杂和硫杂稠五环分子的合成与性能研究

设计合成了含有酰亚胺结构单元的氮杂和硫杂稠五环共轭分子1和2, 并对它们的物理化学性质进行了研究. 实验结果显示酰亚胺基团的引入不仅使得分子具有良好的溶解性, 而且有效地降低分子的HOMO和LUMO能级. 化合物1的单晶结构显示其共轭核具有良好的平面性. 单晶中, 化合物1通过强的π-π相互作用形成二聚体, 二聚体之间存在强的氢键相互作用. 基于化合物2的薄膜场效应晶体管表现出p-型场效应晶体管行为, 其最高迁移率为2.75×10^-3 cm²·V^-1·s^-1.     

利用给体-π-受体分子模板在Au(111)电极表面构筑富勒烯带状结构(英文)

富勒烯与功能分子之间的电荷作用已经被广泛应用于功能性器件的构筑中.这些功能器件的性能与电极表面的薄膜排布结构有着密切关系.因此,研究电极表面的富勒烯和功能分子的组装结构对这些器件的构筑和功能的发挥有着重要意义.本文利用电化学扫描隧道显微镜技术,在HClO4溶液中系统研究了C60分子与有机电子给体-π-受体分子C16H33O-I3CNQ[Z-β-(5-hexadecyloxy-1,3,3-trimethyl-2-indolium)-α-cyano-4-styryl dicyanomethanide]在Au(111)电极表面的二维组装结构.研究发现:C16H33O-I3CNQ分子在Au(111)电极表面组装形成具有短程有序性的条陇状结构;而C60分子在C16H33O-I3CNQ模板之上组装形成了带状结构.C60分子带状结构的形成方向受到了C16H33O-I3CNQ分子中电子给体-π-受体部分排列结构的影响.C60分子与C16H33O-I3CNQ分子之间的π-π堆积作用和电荷转移作用对这种带状结构的形成有着密切关系.这一结果为利用富勒烯和功能分子之间的作用构筑功能器件提供了一种新的制备方法.     

结构对称齐聚(3-甲基噻吩)的电子结构和分子堆积

研究了一类结构对称的新型齐聚(3-甲基噻吩)(二聚体Br2MT和四聚体Br4MT)的电子结构和分子堆积形式.结果表明,随着链的增长,新合成的Br4MT溶液比Br2MT溶液(溶剂CHCl3)的最大紫外吸收波长红移约60 nm,Br2MT和Br4MT的π电子轨道重叠度及斯托克斯位移均较大;广角XRD晶体结构分析表明,该类齐聚(3-甲基噻吩)的π-π堆积晶面间距比聚(3-烷基噻吩)减小了约0.08 nm,分子堆积形式主要为π-共轭平面的堆积,其分子结构趋向于紧密堆积.该结构对称齐聚(3-甲基噻吩)的电子结构和分子堆积形式有利于提高其电荷传输能力.     

Effects of silica nanoparticle addition on polymer semiconductor wettability and carrier mobility in solution‐processable organic transistors on hydrophobic substrates

The effects of the addition of silica nanoparticles (SNPs) on wettability of regioregular poly(3‐hexylthiophene) (P3HT) organic semiconductor solutions on hydrophobic substrates and the carrier mobility in organic field‐effect transistors (OFETs) made of these films are investigated. The dewetting of films made from P3HT solutions on hydrophobic substrates modified with octadecyltrichlorosilane (ODTS) is markedly suppressed after the addition of SNPs with phenyl surfactants. This enables us to fabricate continuous P3HT/SNPs films with high crystallinity by the conventional spin‐coating technique, leading to higher mobility compared with P3HT FETs fabricated on non‐modified substrates. Moreover, the addition of SNPs with larger diameters compensates for the degradation of mobility associated with the increase in the concentration of SNPs. Solution‐processed P3HT/SNPs FETs on ODTS‐modified substrates exhibit a field‐effect mobility of 1.3 × 10^?2 cm² V^?1 s^?1, which is almost comparable to that of P3HT FETs without SNPs (2.1 × 10^?2 cm² V^?1 s^?1). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 509–516     

溶液法制备氧化锌半导体薄膜及其顶栅极晶体管器件

采用旋涂法用浓度分别为0.05,0.10和0.25 mol·L^-1的氧化锌前躯体溶液制备了氧化锌薄膜,并且制备了基于氧化锌多层膜的顶栅极晶体管器件,其中以利用光刻工艺刻蚀的氧化铟锡为源漏电极。通过原子力显微镜(AFM)和X-射线衍射(XRD)分别表征了薄膜的形貌以及结晶情况,并且讨论了前躯体的浓度顺序对氧化锌多层膜的影响。按照浓度从大到小的顺序依次旋涂前躯体溶液制备的氧化锌薄膜表现出了较高的载流子迁移率(7.1×10^-3 cm²·V^-1·s^-1),而按照浓度从小到大的顺序依次旋涂前躯体溶液制备的氧化锌薄膜的载流子迁移率为5.2×10^-3 cm²·V^-1·s^-1。文中通过对两种多层薄膜的形貌和结晶性能的分析表明影响顶栅极薄膜晶体管性能的主要因素是薄膜的粗糙度。平整的薄膜有利于形成较好的半导体层/绝缘层接触界面,从而有利于提高器件的载流子迁移率。     

Structural transitions of nanocrystalline domains in regioregular poly(3‐hexyl thiophene) thin films

The effects of solution processing and thermal annealing on thin film morphology and crystalline structures of regioregular poly(3‐hexyl thiophene) (RR P3HT) are studied in terms of molecular weight (M_w). Using grazing‐incidence X‐ray diffraction, π‐conjugated planes in drop‐cast films from chloroform solutions are found to be preferentially oriented parallel to the substrates regardless of M_w. However, the mesoscale nanocrystalline morphology of the drop‐cast films is significantly affected by M_w, exhibiting a distinctive morphological transition from short nanorods to long nanofibrils above a critical number‐averaged M_w (～ 3.6 kDa). This is probably due to the change in a conformation change from an extended‐chain to a folded‐chain, as M_w of RR P3HT increases. In contrast, spin‐casting of high M_w RR P3HT produces less ordered films with a lower crystallinity and mixed parallel/perpendicular orientations of π‐conjugated planes. The crystallinity and parallel π‐conjugated orientation of RR P3HT in spin‐cast films could be improved by thermal treatments at high‐temperatures either (1) above the glass transition temperature or (2) above the melting temperature of RR 3PHT followed by recrystallization upon cooling under vacuum. However, the charge mobility of the spin‐cast films for a field‐effect transistor application is still lower than that of the drop‐cast films. This would be attributed to the chain oxidation and the development of distinct grain boundaries between RR P3HT nanofibrils during the thermal treatments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1303–1312, 2007     

Electro‐optical properties of electropolymerized poly(3‐hexylthiophene)/carbon nanotube composite thin films

3‐hexylthiophene was electropolymerized on a carbon nanotube (CNT)‐laden fluorine‐doped tin oxide substrate. Scanning electron microscopy and Raman spectroscopy revealed that the polymer was infused throughout the thickness of the 150‐nm thick CNT mat, resulting in a conducting composite film with a dense CNT network. The electropolymerized poly(3‐hexylthiophene) (e‐P3HT)/CNT composites exhibited photoluminescence intensity quenching by as much as 92% compared to the neat e‐P3HT, which provided evidence of charge transfer from the polymer phase to the CNT phase. Through‐film impedance and J‐V measurements of the composites gave a conductivity (σ) of 1.2 × 10^?10 S cm^?1 and zero‐field mobility (μ₀) of 8.5 × 10^?4 cm² V^?1 s^?1, both of which were higher than those of neat e‐P3HT films (σ = 9.9 × 10^?12 S cm^?1, μ₀ = 3 × 10^?5 cm² V^?1 s^?1). In electropolymerized samples, the thiophene rings were oriented in the (010) direction (thiophene rings parallel to substrate), which resulted in a broader optical absorbance than for spin coated samples, however, the lack of long‐range conjugation caused a blueshift in the absorbance maximum from 523 nm for unannealed regioregular P3HT (rr‐P3HT) to 470 nm for e‐P3HT. Raman spectroscopy revealed that π‐π stacking in e‐P3HT was comparable to that in rr‐P3HT and significantly higher than in regiorandom P3HT (ran‐P3HT) as shown by the principal Raman peak shift from 1444 to 1446 cm^?1 for e‐P3HT and rr‐P3HT to 1473 cm^?1 for ran‐P3HT. This work demonstrates that these polymer/CNT composites may have interesting properties for electro‐optical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1269–1275, 2011     

Regioregular poly(3‐alkanoylthiophene): Synthesis and electrochemical,photophysical, charge transport,and photovoltaic properties

Head‐to‐tail regioregular poly(3‐heptanoylthiophene) (PHOT) was synthesized by Ni‐catalyzed polycondensation of the 2,2‐dimethyl‐1,3‐propanediol‐protected Grignard monomer followed by deprotection. Cyclic voltammetric (CV) study demonstrates that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PHOT are 0.5 eV lower in energy than those of the head‐to‐tail poly(3‐hexylthiophene) (HT‐P3HT). Their optical band gaps are essentially the same. Incomplete photoluminescence (PL) quenching was observed in thin films of the 1:1 blend of PHOT and HT‐P3HT. PHOT displayed a glass transition at ～269 °C and decomposed at ～300 °C according to differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Wide‐angle X‐ray diffraction (WAXD) study showed that PHOT exists in a not highly ordered state in solid films especially in the π‐stacking direction. Only p‐channel activity was observed in field‐effect transistors (FETs) for PHOT. The hole mobility was on the order of 10^?4 cm² V^?1 s^?1. Photovoltaic devices with an active layer of 1:1 blend of PHOT and PC₇₁BM had a power conversion efficiency (PCE) of ～0.5%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Structure of friction-transferred highly oriented poly(3-hexylthiophene) thin films

Oriented thin films of P3HT were obtained by a friction-transfer technique. The morphology and structure of the film were studied by means of optical microscopy, atomic force microscopy and transmission electron microscopy. Optical microscopy observation indicates that large size well-ordered P3HT thin films can be produced by a friction-transfer technique. Highly ordered lamellae were observed in P3HT friction-transferred films by electron microscopy. Electron diffraction results confirm the existence of high orientation with the a- and c-axes of P3HT crystals aligned in the film plane while the c-axis parallel to the friction-transfer direction. The atomic force microscopy observation of the as-prepared P3HT thin film shows, however, a featureless top surface morphology, indicating the structure inhomogeneity of the obtained film. To get highly oriented P3HT thin films with homogenous structure, high temperature annealing, solvent vapor annealing and self-seeding recrystallization of the friction-transferred film were performed. It is confirmed that solvent vapor annealing and self-seeding recrystallization methods are efficient in improving the surface morphology and structure of the frictiontransferred P3HT thin film. Highly oriented P3HT films with unique structure can be obtained through friction-transfer with subsequent solvent vapor annealing and self-seeding recrystallization.     

Synergistic Effects of Solvent Vapor Assisted Spin-coating and Thermal Annealing on Enhancing the Carrier Mobility of Poly(3-hexylthiophene) Field-effect Transistors

Poly(3-hexylthiophene)(P3 HT) thin films, obtained by normal spin-coating and solvent vapor assisted spin-coating(SVASP) before and after thermal annealing(TA), and the corresponding devices were prepared to unravel the microstructure-property relationship, which is of great importance for the development of organic electronics. When SVASP-TA films were used as the active layers of the organic field-effect transistors,a hole mobility up to 0.38 cm~2·V~(–1)·s~(–1) was achieved. This mobility was one of the highest values and one order of magnitude higher than that of the normal spin-coating films based transistors. The relationship between the microstructure and the device performance was fully investigated by UV-Vis absorption spectra, grazing incident X-ray diffraction(GIXD), and atomic force microscopy(AFM). The impressive mobility was attributed to the high crystallinity and ordered molecule packing, which stem from the synergistic effects of SVASP and thermal annealing.     

Synthesis and characterization of cyclic P3HT as a donor polymer for organic solar cells

In this study, cyclic poly(3‐hexylthiophene‐2,5‐diyl) (c‐P3HT) with a controlled M_n was synthesized by the intramolecular cyclization of α‐bromo‐ω‐ethynyl‐functionalized P3HT via the Sonogashira coupling reaction. The effect of the cyclic structure, which does not have terminal groups of polymers, on the photoelectric conversion characteristics was investigated in comparison to linear P3HT (l‐P3HT). c‐P3HT was successfully synthesized with M_n ≈ 17,000, dispersity ≈ 1.2, and regioregularity ≈ 99%. The hole mobility was determined to be 5.1 × 10^?4 cm² V^?1 s^?1 by time‐of‐flight (TOF) experiment. This was comparable to that of l‐P3HT of 5.6 × 10^?4 cm² V^?1 s^?1. Organic solar cell systems were fabricated with each polymer by blending them with [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM). The l‐P3HT:PC₇₁BM system showed a dispersive TOF photocurrent profile for electron transport, whereas a nondispersive profile was observed for c‐P3HT:PC₇₁BM. In addition, an amount of collected electrons in c‐P3HT:PC₇₁BM was greater than that in l‐P3HT:PC₇₁BM for TOF experiments. The photoelectric conversion characteristics were improved by using c‐P3HT rather than l‐P3HT (power conversion efficiency [PCE] = 4.05% vs 3.23%), reflecting the nondispersive transport and the improvement of electron collection. PCEs will be much improved by applying this cyclic concept to highly‐efficient OSC polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 266–271     

Correlation of charge transport with structural order in highly ordered melt‐crystallized poly(3‐hexylthiophene) thin films

A series of well‐defined poly(3‐hexylthiophene)s (P3HT) of different molecular weight (MW) and high regioregularity was investigated for charge transport properties in as‐cast and melt‐crystallized films. The semicrystalline structure of the P3HT was characterized by X‐ray scattering and Atomic force microscopy. Crystallization by cooling from the melt led to a substantial increase in crystallinity and a stronger alignment of the crystals in comparison to as‐cast films. The increase in crystallinity went along with an increase in hole mobility of up to an order of magnitude as measured by the space charge limited current method. Additionally, the hole mobility depended on the long period of P3HT lamellae and consequently on the MW. In compliance with the long period, the charge carrier mobility first increased with the MW before decreasing again at the onset of chain folding. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 943–951     

Novel Conjugated Polymers Based on Dithieno[3,2‐b:6,7‐b]carbazole for Solution Processed Thin‐Film Transistors

Two conjugated polymers (CPs) P‐tCzC12 and P‐tCzC16 comprising alternating dithieno[3,2‐b:6,7‐b]carbazole and 4,4′‐dihexadecyl‐2,2′‐bithiophene units have been designed and synthesized. Upon thermal annealing, they can form ordered thin films in which the polymer backbones dominantly adopted an edge‐on orientation respective to the substrate with a lamellar spacing of ≈24 Å and a π‐stacking distance of ≈3.7 Å. Organic thin‐film transistors (OTFTs) were fabricated by solution casting. A hole mobility of 0.39 cm² V⁻¹s⁻¹ has been demonstrated with P‐tCzC16. This value is the highest among the CPs containing heteroacenes larger than 4 rings.