Recent progress of interface self-assembled monolayers engineering organic optoelectronic devices

Numerous reports have suggested that the performance of organic optoelectronic devices based on organicfieldeffect transistors(OFETs)is largely dependent on their interfaces.Self-assembled monolayers(SAMs)have been commonly used to engineer the interfaces of high-performance devices,particularly due to their well-defined structures and simple operation process through simple chemical adsorption growth.In this review,the structures of OFETs and SAM-modified OFETs are described,while different SAMs have been characterized.Furthermore,recent advances in the interface engineering of OFETs are described,the applicability of SAMs in functional devices of OFETs is reviewed,and existing problems and future developments in thisfield have been identified.

Organic optoelectronics:materials,devices and applications

The interest in organic materials for optoelectronic devices has been growing rapidly in the last two decades. This growth has been propelled by the exciting advances in organic thin films for displays, low-cost electronic circuits, etc. An increasing number of products employing organic electronic devices have become commercialized, which has stimulated the age of organic optoelectronics. This paper reviews the recent progress in organic optoelectronic technology. First, organic light emitting electroluminescent materials are introduced. Next, the three kinds of most important organic optoelectronic devices are summarized, including light emitting diode, organic photovoltaic cell, and photodetectors. The various applications of these devices are also reviewed and discussed in detail. Finally, the market and future development of optoelectronic devices are also demonstrated.

A simple encapsulation method for organic optoelectronic devices

The performances of organic optoelectronic devices, such as organic light emitting diodes and polymer solar cells, have rapidly improved in the past decade. The stability of an organic optoelectronic device has become a key problem for further development. In this paper, we report one simple encapsulation method for organic optoelectronic devices with a parafilm, based on ternary polymer solar cells （PSCs）. The power conversion efficiencies （PCE） of PSCs with and without encapsulation decrease from 2.93% to 2.17% and from 2.87% to 1.16% after 168-hours of degradation under an ambient environment, respectively. The stability of PSCs could be enhanced by encapsulation with a parafilm. The encapsulation method is a competitive choice for organic optoelectronic devices, owing to its low cost and compatibility with flexible devices.

Effect of Organic Dopants in Dimetallophthalocyanine Thin Films: Application to Optoelectronic Devices

Semiconductor films of organic, doped dimetallophthalocyanine M2Pcs (M = Li, Na) on different substrates were prepared by synthesis and vacuum evaporation. Tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ) were used as dopants and the structure and morphology of the semiconductor films were studied using IR spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). The absorption spectra recorded in the ultraviolet-visible region for the deposited films showed the Q and Soret bands related to the electronic π-π* transitions in M2Pc molecules. Optical characterization of the films indicates electronic transitions characteristic of amorphous thin films with optical bandgaps between 1.2 and 2.4 eV. Finally, glass/ITO/doped M2Pc/Ag thin-film devices were produced and their electrical behavior was evaluated by using the four-tip collinear method. The devices manufactured from Na2Pc have a small rectifying effect, regardless of the organic dopant used, while the device manufactured from Li2Pc-TCNQ presents ohmic-like behavior at low voltages, with an insulating threshold around 19 V. Parameters such as the hole mobility (μ), the concentration of thermally-generated holes (p0), the concentration of traps per unit of energy (P0) and the total trap concentration (Nt(e)) were also determined for the Li2Pc-TTF device.

Enhancement of electroluminescent properties of organic optoelectronic integrated device by doping phosphorescent dye

Organic optoelectronic integrated devices（OIDs） with ultraviolet（UV） photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence（TADF） material 4, 5-bis（carbazol-9-yl）-1, 2-dicyanobenzene（2 CzPN） as host. The OIDs doping with typical red phosphorescent dye [tris（1-phenylisoquinoline）iridium（Ⅲ）, Ir（piq）3], orange phosphorescent dye {bis[2-（4-tertbutylphenyl）benzothiazolato-N,C-（2＇）]iridium（acetylacetonate）,（tbt）2 Ir（acac）}, and blue phosphorescent dye [bis（2, 4-di-fluorophenylpyridinato）-tetrakis（1-pyrazolyl）borate iridium（Ⅲ）, FIr6] were investigated and compared. The（tbt）2 Ir（acac）-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the（tbt）2 Ir（acac）-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m^2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10^11 Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.

Spectroscopic Analysis and Study of Charge Transport Properties for Pinacyanol Chloride-Organic Acceptor Complex as Potential Optoelectronics Material

Organic photoconductor, pinacyanol chloride, has been studied with infrared spectroscopy because of its thermal activation energy (Ea) and band gap (Eg = 2Ea) lying in the infrared range. Particularly, pinacyanol chloride and its charge transfer (CT) complexes with chloranil, DDQ, TCNQ and TCNE as organic acceptors are studied in details. The CT complexes are having neither two absorption edges like ternary complex having one donor and two acceptors nor binary type with Lorentzian or Gaussian envelopes. The forbidden gap is direct band gap except chloranil complex due to increase in molecular distance and CT interaction. There is imperfect nesting and partial screening determining the mid-IR envelope, which is qualitatively different from the envelopes in binary systems. There is inverted parabola in some range below this envelope. It is explained how infrared absorption is related with the applications of such organic photoconductors in optoelectronic devices.

Organic near-infrared optoelectronic materials and devices:an overview

Near-infrared(NIR)light has shown great potential for military and civilian applications owing to its advantages in the composition of sunlight,invisibility to human eyes,deeper penetration into biological tissues,and low optical loss in optical fibers.Therefore,organic optoelectronic materials that can absorb or emit NIR light have aroused great scientific interest in basic science and practical applications.Based on these NIR organic optoelectronic materials,NIR optoelectronic devices have been greatly improved in performance and application.In this review,the representative NIR organic optoelectronic materials used in organic solar cells,organic photodetectors,organic light-emitting diodes,organic lasers,and organic optical waveguide devices are briefly introduced,and the potential applications of each kind of device are briefly summarized.Finally,we summarize and take up the development of NIR organic optoelectronic materials and devices.

Enhancing light absorption for organic solar cells using front ITO nanograting and back ultrathin Al layer

To address the discrepancy between carrier collection and light absorption of organic solar cells caused by the limited carrier mobility and optical absorption coefficient for the normally employed organic photoactive layers,a light management structure composed of a front indium tin oxide(ITO)nanograting and ultrathin Al layer inserted in between the photoactive layer and the electron transport layer(ETL)is introduced.Owing to the antireflection and light scattering induced by the ITO nanograting and the suppression of light absorption in the ETL by the inserted Al layer,the light absorption of the photoactive layer is significantly enhanced in a spectral range from 400 nm to 650 nm that also covers the main energy region of solar irradiation for the normally employed active materials such as the P3HT:PC_(61)BM blend.The simulation results indicate that comparing with the control device with a planar configuration of ITO/PEDOT:PSS/P3HT:PC_(61)BM(80-nm thick)/ZnO/Al,the short-circuit current density and power conversion efficiency of the optimized light management structure can be improved by 32.86%and 34.46%.Moreover,good omnidirectional light management is observed for the proposed device structure.Owing to the fact that the light management structure possesses the simple structure and excellent performance,the exploration of such a structure can be believed to be significant in fabricating the thin film-based optoelectronic devices.

Flexible optoelectronic devices based on metal halide perovskites

The unique physical and chemical properties of metal halide perovskites predestine the devices to achieve high performance in optoelectronic field.Among the numerous high qualities of perovskites,their different low-temperature synthesis methods and preparation processes make them impressive and popular materials for flexible optoelectronic devices.Mainstream perovskite devices,for instance,solar cells,photodetectors and light-emitting diodes,have been fabricated on flexible substrates and show outstanding flexibility as well as high performance.For soft wearable electronic systems,mechanical flexibility is the premier condition.Compared to common devices based on rigid substrates,flexible perovskite devices are more practical and see widespread applications in energy,detection,display,and other fields.This review summarizes the recent progress of flexible perovskite solar cells,photodetectors and light-emitting diodes.The design and fabrication of different high-performance flexible perovskite devices are introduced.Various low-dimensional perovskite materials and configurations for flexible perovskite devices are presented.In addition,the limitations and challenges for further application are also briefly discussed.

CuPc/C_(60) heterojunction thin film optoelectronic devices

The optoelectronic properties of heterojunction thin film devices with ITO/CuPc/C_（60）/Al structure have been investigated by analyzing their current-voltage characteristics,optical absorption and photocurrent.In this organic photovoltaic device,CuPc acts as an optically active layer,C_（60） as an electron-transporting layer and ITO and Al as electrodes.It is observed that,under illumination,excitons are formed,which subsequently drift towards the interface with C_（60）,where an internal electric field is present.The excitons that reach the interface are subsequently dissociated into free charge carriers due to the electric field present at the interface.The experimental results show that in this device the total current density is a function of injected carriers at the electrode-organic semiconductor surface,the leakage current through the organic layer and collected photogenerated current that results from the effective dissociation of excitons.

卟啉类光电功能材料的研究进展

卟啉及其衍生物是一类具有优良的光电性能的有机半导体材料,引起人们广泛的关注。本文对卟啉类光电材料在模拟生物光合作用中心的光致电荷转移和能量转移,有机太阳能电池,分子光电器件,有机电致发光和光存储等领域的研究进展做一简要介绍。

有机光电材料载流子迁移率的研究方法与技术

测量有机光电材料的载流子迁移率,有助于了解载流子在有机光电器件中的传递机制。通过对几种有机光电材料载流子迁移率的测试方法详细的阐述与对比分析,深入理解各种测试技术的原理,有助于学生掌握各种测试技术的实验方法,总结出各种测试技术的优劣及适用性,对研究载流子在有机光电材料中的传输特性及有机光电器件的性能具有重要意义。

气溶胶喷墨打印在有机器件制备中的应用

气溶胶喷墨打印是近年来新出现的一种打印技术。通过将形成的墨水气溶胶喷射至基底表面而成膜,使得气溶胶喷墨打印对墨水的黏度要求低、打印分辨率好、适用墨水的范围广。文章对气溶胶喷墨打印技术的基本原理、在有机器件制备方面的应用以及将来的改进等方面进行了简介和评价。

柔性有机电致发光器件的研究进展

柔性OLED技术尚未成熟,要实现产业化,其稳定性和显示效率仍有待进一步改善.本文从FOLED衬底材料的选取和处理、阳极材料的选取和设计、柔性器件的包封等方面。介绍了FOLED几项关键技术研究进展,并对其研究与应用前景进行了展望。

蓝光OLED的掺杂研究

采用蓝色发光材料ADN为主体发光材料、BAlq3为掺杂材料,通过改变BAlq3的掺杂浓度制备了结构为ITO／NPB／ADN:BAlq3／Alq3／Mg:Ag的一系列蓝光有机发光器件(OLED)。研究了器件各有机层之间的能级匹配和BAlq3的掺杂浓度对载流子注入、传输、复合以及发光色纯度的影响。实验结果表明,空穴阻挡材料BAlq3的掺入显著影响OLED的电流密度、发光亮度、发光效率和发光光谱,当BAlq3的掺杂浓度为25％时,OLED的发光效率为1．0 lm／W,发光光谱的峰值为440 nm,色纯度为(0．18,0．15),未封装器件的半衰期为950小时,器件同时满足了高效率和高色纯度的要求。

红荧烯晶体薄膜的制备及应用研究进展

红荧烯具有导电性好、吸收系数高等优良的荧光特性和半导体特性,是目前报道的单晶迁移率最高的材料,在有机光电器件中有很好的发展前景,受到科研人员的广泛关注。目前国内外主要采用真空蒸镀方法和溶液加工方法制备红荧烯晶体薄膜,采用各种制备工艺来提高红荧烯薄膜质量。本文在系统介绍红荧烯晶体薄膜制备工艺研究进展的基础上,归纳总结了掺杂种类/聚合物浓度、后处理工艺/实验温度等对红荧烯晶体性能的影响,简要概述了红荧烯薄膜在有机光电子器件应用研究中所取得的研究成果,最后展望了基于红荧烯晶体薄膜的光电器件的发展趋势。

基于聚苯撑苯并二恶唑的多功能光电器件

首次报道了基于全共轭高分子材料聚苯撑苯并二恶唑(PBO)作为空穴传导材料及电子给体,富勒烯(C60)作为电子传输层及电子受体的双层异质结器件.研究发现:该结构器件具有明显的光伏响应特征,开路电压达0.76 V,短路电流0.07 mA/cm2;而且在正向偏压下,器件还表现出了较强的激基复合物电致发光现象,在7.1 V偏压下,器件的亮度达5.3×103 cd/m2,而器件的最高发光效率可达1.8 cd/A.该研究表明,基于PBO/C60双层异质结的多功能光电器件具有较好的开发价值和应用前景.

氮杂苯并菲类n-型有机半导体材料研究进展

苯并菲盘状液晶是一类新型的有机电子学材料.该类材料多数以空穴传输功能为主,能传输电子的n-型材料较少.氮杂苯并菲是与苯并菲衍生物非常相似的一种杂环化合物,材料结构中引入了氮原子,吸电子能力得到增强,是潜在的n-型有机半导体材料,具有重要的应用价值.本文系统回顾了氮杂苯并菲类盘状液晶材料的研究进展,分类讨论了材料的分子结构,其中包括二、四、六氮杂苯并菲,以及它们的合成方法和物理化学性能,论述了材料在光电子领域的最新使用进展,并在此基础上,对该类液晶材料作为n-型有机半导体在光电子器件领域的应用前景进行了展望.

有机/聚合物光电子学器件的应用与研究进展

调研了有机 /聚合物光电子学器件在制备技术和应用方面的近期进展。其中包括 :电光调制器在CATV、高比特网络、相阵列系统、计算机系统的平行互连等工业领域的应用前景等。聚合物调制器正迅速接近商品化 ;聚合物热光开关已在AKZONOBEL公司批量生产 ;其它有机 /聚合物器件和相关技术 ,如互连、聚合物激光器、波导中的 45°镜片、垂直集成波导以及在波导中与有机发光二极管的集成等。至少部分聚合物器件包括电光调制器 ,现在已经是或即将成为信息高速公路工业中实际可用的硬件。

有机光电材料与有机光电器件

近年来,有机光电子学在基础研究和应用方面取得了突飞猛进的发展,已经成为一个较为成熟的跨学科新兴领域。主要介绍有机光电材料的分子结构、导电与发光机理、有机光电器件的分类与工作原理以及有机光电材料在光电器件方面的应用,包括有机发光二极管和发光电化学池、有机太阳能电池、有机场效应晶体管、有机生物化学传感器、有机光泵浦激光器以及有机非线性光学材料等。