基于聚(4-乙烯基苯酚)衬底修饰层喷墨打印的小分子有机半导体薄膜制备和表征

采用旋涂法预先在SiO2衬底表面形成一层聚(4-乙烯基苯酚)(PVP)作为表面修饰层,以喷墨打印的6,13-双(三异丙基甲硅烷基乙炔基)并五苯(TIPS并五苯)作为有源层制作有机薄膜晶体管,有效改善了有机半导体薄膜的形貌。采用真空热蒸镀工艺制备源漏电极,形成底栅顶接触结构的有机薄膜晶体管(OTFT)器件。作为对比,在未经过表面修饰的SiO2衬底上采用相同条件打印TIPS并五苯薄膜晶体管,发现在经过PVP修饰的SiO2衬底上打印的单点厚度更均匀,咖啡环效应被抑制或被消除;而通过多点交叠打印形成的矩形薄膜的晶粒尺寸更大,相应的OTFT器件具有更高的场效应迁移率。在有PVP修饰层的衬底上制作的OTFT,器件在饱和区的平均场效应迁移率达到了0.065 cm2·V-1·s-1;而直接在SiO2衬底上制作的器件,相应的平均场效应迁移率仅为0.02 cm2·V-1·s-1。     

低电压有机薄膜晶体管驱动顶发射有机发光二极管的集成像素的研制

研究了有机薄膜晶体管(OTFT)驱动顶发射有机发光二极管(OLED)的集成制备技术。通过减小栅绝缘层的厚度,达到降低OTFT工作电压的目的。OLED采用标准的绿光器件,利用超薄的Al薄膜作为半透明阴极实现顶发射功能。实现了低电压工作的OTFT与顶发射OLED的集成,其中OTFT的阈值电压为2.0 V,饱和场效应迁移率为0.40 cm2·V-1·s-1。基于实验数据,对集成像素的电特性进行了计算分析,在-5~-10 V的栅电压调控下,像素亮度能在50~250 cd/m2的范围内实现线性灰度调控。     

有机薄膜晶体管驱动聚合物发光二极管研究

研究了有机薄膜晶体管(OTFT)与聚合物发光二极管(PLED)集成制备技术和相关物理问题.OTFT结构为栅极钽(Ta)/绝缘层五氧化二钽(Ta2O5)/有源层并五苯(Pentacene)/源漏极金(Au);PLED器件结构为ITO/PEDOT:PEO(polyethylene oxide)/P-PPV或MEH-PPV/Ba/Al.PEDOT:PEO,P-PPV和MEH-PPV薄膜层均采用丝网印刷技术,实现了OTFT与PLED器件集成发光.其中OTFT器件的阈值电压为-7V,迁移率为0.91cm2/(V.s),并通过OTFT驱动得到以P-PPV和MEH-PPV为发光层的PLED器件的发光亮度分别达到124和26cd/m2,电流效率分别为12.4和1.1cd/A.利用丝网印刷技术可以有效控制高分子薄膜的沉积区域,实现功能器件的集成.     

基于聚噻吩/聚己内酯共混物的有机薄膜晶体管

选择聚3-己基噻吩(P3HT)/聚己内酯(PCL)双晶共混体系制备了不同配比的共混物有机薄膜晶体管。电学性能研究发现,随着共混物中P3HT含量降低,薄膜晶体管的场效应迁移率、开关电流比和阈值电压等性能缓慢降低。当P3HT质量分数为40%时,共混物薄膜仍具有较好的场效应性能,迁移率为0.008 cm²·V^-1·s^-1,开关电流比为5×10³,阈值电压为45.5 V。原子力显微镜测试结果表明:共混物成膜时发生明显的垂直相分离,在界面处形成连续的半导体层,有利于载流子传输。     

NiO_x作为空穴传输层对有机太阳能电池光吸收的影响

基于多层膜系模型的传输矩阵方法、麦克斯韦方程和光子吸收方程,研究了NiOx作为替代3,4-乙撑二氧噻吩:聚苯乙烯磺酸盐(PEDOT:PSS)的空穴传输材料对聚3-己噻吩(P3HT)和富勒烯衍生物([6,6]-phenyl-C61-butyric acid methyl ester,PC61BM)共混体异质结有机太阳能电池器件内部光电场分布和光吸收特性的影响.分别制备了以NiOx和PEDOT:PSS为空穴传输层,P3HT:PCBM为活性层的有机太阳能电池,并通过数值模拟的方法比较了NiOx和PEDOT:PSS两种空穴传输材料对器件光伏特性的影响.结果表明:10 nm的NiOx空穴传输层器件比40 nm的PEDOT:PSS器件获得了更大的短路电流和填充因子,并具有更高的能量转化效率.     

基于P3HT给体的单/双受体平面异质结电池性能及其介电特性

为了研究分析界面电荷等特性对器件的影响,制备了基于P3HT给体的单/双受体平面异质结(PHJ)有机太阳能电池(OPV)。首先研究了P3HT膜厚、P3HT溶剂和P3HT膜层的干燥时间对器件性能的影响。为了提高P3HT/Sub Pc PHJ电池的性能,采用双受体的三元器件结构(P3HT/Sub Nc/Sub Pc),制备了结构为ITO/PEDOT∶PSS/P3HT/Sub Nc/Sub Pc/BCP/Al的三元瀑布型OPV器件并研究了Sub Nc层厚度对其性能的影响。结果表明,在二元器件(P3HT/Sub Pc)体系中,P3HT溶于氯仿和1,2-二氯苯混合溶剂,成膜后干燥10 min退火获得的器件性能最佳。在三元器件中,随着Sub Nc厚度的增大,器件光电转换效率(PCE)先增大后减小。当Sub Nc厚度为5 nm时,器件PCE达到最大。相比于二元器件,三元器件的各项性能得到明显提升。最后,比较研究了不同厚度Sub Nc薄膜对器件介电特性的影响。     

基于小分子半导体IEICO的高性能倍增型有机光电探测器

采用溶液法制备了结构为ITO/ZnO/P3HT:IEICO/Al和ITO/PEDOT:PSS/P3HT:IEICO/Al的倍增型有机光电探测器,活性层中电子给体(P3HT)和电子受体(IEICO)的质量比为100:1.以氧化锌(ZnO)为界面层的器件在正向与反向偏压下都能良好工作,而以PEDOT:PSS为界面层的器件只...     

最小二乘拟合计算有机薄膜晶体管迁移率的研究

本文通过制备了一个基于并五笨为有源层的顶栅底接触OTFT器件获取电流电压实验数据,并运用电流电压特性曲线理论拟合计算方法计算其场效应迁移率.研究发现,采用不同的拟合方法得到的场效应迁移率值有较大的差异.若选取转移特性曲线线性区距中心1/2范围内测试点进行最小二乘拟合计算出的场效应迁移率能减少采用其他拟合方法的固有不准确性,而且与其他方法得到的场效应迁移率最接近. 关键词： 最小二乘拟合 场效应迁移率 有机薄膜晶体管     

多层栅介质层有机薄膜晶体管的存储与光响应特性

在真空室内一次性制备了具有多层栅介质层结构的有机薄膜晶体管(OTFTs).结果表明,制备的OTFTs具有电控开关、存储和光敏多重功能特性.分析认为,存储特性归功于器件的结构,采用了分离的CaF2纳米粒子岛作为电荷俘获中心.在光照环境下,观察到了两种不同类型的光响应特性.快速的光响应来自于有源层吸收了能量大于带隙的光子所...     

基于聚(4-乙烯基苯酚)衬底修饰层喷墨打印的小分子有机半导体薄膜制备和表征

采用旋涂法预先在SiO₂衬底表面形成一层聚（4-乙烯基苯酚）（PVP）作为表面修饰层,以喷墨打印的6,13-双（三异丙基甲硅烷基乙炔基）并五苯（TIPS并五苯）作为有源层制作有机薄膜晶体管,有效改善了有机半导体薄膜的形貌。采用真空热蒸镀工艺制备源漏电极,形成底栅顶接触结构的有机薄膜晶体管（OTFT）器件。作为对比,在未经过表面修饰的SiO₂衬底上采用相同条件打印TIPS并五苯薄膜晶体管,发现在经过PVP修饰的SiO₂衬底上打印的单点厚度更均匀,咖啡环效应被抑制或被消除;而通过多点交叠打印形成的矩形薄膜的晶粒尺寸更大,相应的OTFT器件具有更高的场效应迁移率。在有PVP修饰层的衬底上制作的OTFT,器件在饱和区的平均场效应迁移率达到了0.065 cm²·V^-1·s^-1;而直接在SiO₂衬底上制作的器件,相应的平均场效应迁移率仅为0.02 cm²·V^-1·s^-1。     

Laser printing and characterization of semiconducting polymers for organic electronics

Hybrid organic/inorganic thin-film transistors (TFTs) with bottom-contact configuration were fabricated using the Laser Induced Forward Transfer (LIFT) process. The semiconducting polymer P3HT was laser printed from a donor to a receiver substrate in order to form the active layer of the TFTs. With a single laser pulse, P3HT pixels were successfully printed. The printed material was analyzed morphologically by means of Optical Microscopy and its thickness was measured by profilometry. In addition, structural characterization of P3HT thin films before and after laser printing took place by using UV-Visible absorption spectroscopy and X-Ray Diffraction. It was found that the crystallinity of the investigated films is improved upon annealing. An organic thin-film transistor (OTFT) with laser printed P3HT pixel as a channel layer was then fabricated. The OTFTs indicated a field-effect mobility up to 2.23?10^?4 cm²/Vs and an on/off ratio on the order of 10–100.     

旋涂速度对制备P3HT有机场效应晶体管性能的影响

采用溶液化的方法制备了以PMMA为绝缘层、P3HT为有源层的有机场效应晶体管.研究了P3HT有源层和PMMA绝缘层的旋涂速度对器件性能的影响.实验结果表明,当P3HT和PMMA的旋涂速度均为2 000 r/min时,器件的性能最佳.峰值场效应迁移率为6.84×10^-2 cm²·V^－1·s^－1.结果表明,选择适当的旋涂速度是一种有效提高溶液化制备有机场效应晶体管性能的方法.     

Polaron and ion diffusion in a poly(3-hexylthiophene) thin-film transistor gated with polymer electrolyte dielectric

Electrolytes are finding applications as dielectric materials in low-voltage organic thin-film transistors (OTFT). The presence of mobile ions in these materials (polymer electrolytes or ion gels) gives rise to very high capacitance (>10 μF/cm²) and thus low transistor turn-on voltage. In order to establish fundamental limits in switching speeds of electrolyte gated OFETs, we carry out in situ optical spectroscopy measurement of a poly(3-hexylthiophene) (P3HT) OTFT gated with a LiClO₄:poly(ethyleneoxide) (PEO) dielectric. Based on spectroscopic signatures of molecular vibrations and polaron transitions, we quantitatively determine charge carrier concentration and diffusion constants. We find two distinctively different regions: at V _G≥−1.5 V, drift-diffusion (parallel to the semiconductor/dielectric interface) of hole-polarons in P3HT controls charging of the device; at V _G<−1.5 V, electrochemical doping of the entire P3HT film occurs and charging is controlled by drift/diffusion (perpendicular to the interface) of ClO₄ ⁻ counter ions into the polymer semiconductor.     

Organic passivation layers for pentacene organic thin-film transistors

We studied the passivation layers for pentacene organic thin-film transistors (OTFTs) that were used to drive the active-matrix organic-light-emitting-diodes (AMOLEDs) fabricated by inkjet process. Conventional polyvinyl acetate (PVA) passivation layer could not protect OTFT channel from poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) inkjet process so that the performance was degraded critically after the process. By applying PVA/PVA/photoacryl (PA) multi-passivation layers, we could get OTFT arrays with switching ratio over 10⁶ even after PEDOT:PSS process. Using these OTFTs, we could drive AMOLEDs made by inkjet process.     

Characteristics of pentacene organic thin film transistor with top gate and bottom contact

High performance pentacene organic thin film transistors (OTFT) were designed and fabricated using SiO₂ deposited by electron beam evaporation as gate dielectric material. Pentacene thin films were prepared on glass substrate with S--D electrode pattern made from ITO by means of thermal evaporation through self-organized process. The threshold voltage V_TH was --2.75± 0.1V in 0---50V range, and that subthreshold slopes were 0.42± 0.05V/dec. The field-effect mobility (μ_EF) of OTFT device increased with the increase of V_DS, but the μ_EF of OTFT device increased and then decreased with increased V_GS when V_DS was kept constant. When V_DS was --50V, on/off current ratio was 0.48× 10⁵ and subthreshold slope was 0.44V/dec. The μ_EF was 1.10cm²/(V.s), threshold voltage was --2.71V for the OTFT device.     

Mobility Enhancement of P3HT‐Based OTFTs upon Blending with Au Nanorods

The mobility enhancement of organic thin‐film transistors based on poly(3‐hexylthiophene) (P3HT) by incorporating gold nanorods (Au NRs) is reported. Through varying the doping concentration and surface modifier of the Au NRs in P3HT matrix, the P3HT/Au composite with 0.5 mg mL^?1 pyridine‐capped Au NRs exhibits a hole mobility of 0.059 cm² V^?1 s^?1, this value is seven times higher than that of pristine P3HT. This remarkable improvement of mobility originates from the enhanced crystallinity and optimized orientation of P3HT after doping with Au NRs. In addition, the appropriate surface modification can produce more‐efficient hole conduction of Au NRs.     

Investigation of photo-induced change of electro-optical performance in a liquid crystal-organic field effect transistor (LC-OFET)

This study aimed to improve the electrical characteristics of poly(3-hexylthiophene) (P3HT) and liquid crystal-organic field effect transistors (LC-OFETs) under UV illumination. Consequently, a novel LC-OFET was fabricated using a nematic liquid crystal (E63) and a P3HT mixture in an OFET cell. Cell thickness was determined through field emission scanning electron microscopy. For assessment of the electrical characteristics, the LC-OFET device was exposed to various UV light intensities in total darkness for the purpose of obtaining the output- and transfer-current voltage. The capacitance–frequency plot of the capacitor cell was then measured to determine the main parameters including the threshold voltage (V_Th), field effect mobility (μ_FET) and current on/off ratio (I_on/off) of the device. Thus, the full characterisation and UV light response of the electronic parameters were determined for this new class of transistors. Results showed that the new LC-OFET exhibited good performance in the form of low V_Th, high μ_FET, and high I_on/off.     

Poly(3‐hexylthiophene)/Gold Nanoparticle Hybrid System with an Enhanced Photoresponse for Light‐Controlled Electronic Devices

Light‐controlled electrical behavior of polymer/nanoparticle hybrid system in ambient condition is demonstrated. By embedding gold nanoparticles (Au NPs) in a poly(3‐hexylthiophene) (P3HT) matrix, the photoresponses of the nanocomposite films are enhanced. The electrical behavior of the P3HT/Au NPs nanocomposite transistors and inverters are tuned over a wide range in depletion mode. UV‐visible absorption spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and steady‐state photoluminescence (PL) spectroscopy are used to analyze the nanocomposite films. The findings provide a better understanding of light‐induced threshold voltage shifts of P3HT‐based field‐effect transistors and inverters and demonstrate their potential applications in electronic signal modulation for solution‐processed integrated circuits.     

高效钙钛矿-有机本体异质结杂化串联太阳能电池

制备了一种有机铅卤钙钛矿-有机本体异质结杂化串联太阳能电池。采用紫外可见吸收光谱、原子力显微镜对薄膜形貌进行了表征。结果表明:有机本体异质结层可以有效改善钙钛矿的表面形貌, 增强了可见光的吸收。优化后的串联结构电池的短路电流可达19.14mA/cm², 开路电压为0.76V, 光电转换效率达到了6.54%。钙钛矿电池和有机本体异质结电池串联结构可以同时提高短路电流及填充因子, 二者具有较好的相容性和协同作用。