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。     

聚合物掺杂有机小分子发光二极管的电致发光与杂质陷阱效应

在新型空穴传输聚合物聚TPD(PTPD)中掺杂电子传输有机小分子荧光染料Rubrene制成薄膜器件.考察了不同掺杂浓度以及不同薄膜厚度器件的电致发光性能,结果表明存在杂质陷阱效应.基于固体中双注入理论，假设杂质陷阱限制在分立能级上，通过求解泊松方程，得到了掺杂器件J-V特性解析模型.该模型的计算值与实验结果一致.     

B原子的掺杂对富勒烯C_(32)的电子传输特性与负微分电阻效应的影响

采用基于密度泛涵理论的第一性原理和非平衡格林函数方法研究了硼原子的掺杂对于富勒稀C32分子的电子传输特性与负微分电阻效应的影响.结果显示硼原子的掺杂明显降低了C32分子的电子传输特性,却增强了分子的负微分电阻效应.分析认为,硼原子的掺杂减少了核外电子是导致分子的电子传输性能降低和负微分电阻效应增强的主要原因.本文还研究了掺杂的硼原子的个数多少对C32分子的影响.     

硼氮原子取代掺杂对分子器件负微分电阻效应的影响

利用基于非平衡格林函数和密度泛函理论相结合的第一性原理计算方法,研究了硼氮原子取代掺杂对三并苯分子电子输运性质的影响.计算结果表明,三并苯分子器件的电流在特定偏压区间内随电压的增加而减小呈现出负微分电阻效应,电流的峰谷之比高达5.12.用硼原子或者氮原子取代分子的中心原子后,器件0.8V以内的电流明显增加,但是负微分电阻效应减弱,相应的电流峰谷比分别降至3.83和3.61.分析认为,输运系数在特定偏压下的移动是器件负微分电阻效应的主要成因.核外电子数的差异导致硼氮原子掺杂取代可以使器件轨道及其透射峰分别向高能方向或者低能方向移动从而有效地调控了器件的低偏压下的电子传输能力和负微分电阻效应.     

B原子的掺杂对富勒烯C32的电子传输特性与负微分电阻效应的影响

采用基于密度泛涵理论的第一性原理和非平衡格林函数方法研究了硼原子的掺杂对于富勒稀C32分子的电子传输特性与负微分电阻效应的影响．结果显示硼原子的掺杂明显改变了C32分子的电子传输特性和负微分电阻效应．同时研究了掺杂的硼原子的个数多少对C32分子的影响．     

采用Li3N n型掺杂层作为电子注入层的OLED器件研究

 相对于传统的无机半导体材料,有机半导体材料特别是有机电子传输材料的载流子浓度和迁移率较低,从而影响了有机发光器件的亮度、效率等性能.为了提高有机发光器件器件性能必须增强电子注入和传输能力,对有机电子传输材料进行n型电学掺杂能够有效地提高电子的注入和传输能力.本文利用Li3N作为n型掺杂剂,以掺杂层Alq3∶Li3N作为电子注入层,有效地提高了有机发光器件器件的性能,在掺杂浓度为5%,掺杂层厚度为10 nm时器件性能表现为最优.Li3N在空气中稳定,并且在较低的温度和压强下能分解产生Li原子和氮气,避免了采用金属掺杂剂如Li、Cs等材料时易受空气中水分和氧气影响的缺点,有利于工艺处理.     

基于溶液加工小分子材料发光层的有机-无机复合发光器件

报道了基于溶液加工有机小分子材料发光层、聚乙烯亚胺电子注入层的有机-无机复合发光器件. 优化了空穴传输层和磷光染料的掺杂浓度, 得到最佳发光效率的器件. 蓝光、黄光和红光器件的最大外量子效率为17.3%, 10.7% 和7.3%. 在发光亮度为1000 cd/m² 时, 蓝光、黄光和红光器件的外量子效率分别为17.0%, 10.6% 和5.8%, 器件效率下降较小. 原因在于同时采用空穴传输型和电子传输型的小分子材料作为共同主体材料, 器件具有较宽的载流子复合区域, 降低了三线激发态-三线激发态湮灭和三线激发态-极化子相互作用对器件发光效率的影响. 白光器件在亮度为1000 cd/m²时, 发光效率和功率效率为31 cd/A和 14.8 lm/W. 器件的色度为(0.32, 0.42), 色度比较稳定, 随电流的变化微小. 器件的效率较以往报道的有机-无机复合发光器件有显著的提高, 主要归因于在聚乙烯亚胺上能够制备特性良好的小分子材料薄膜, 以及小分子主体材料拥有较高的三线态能量和平衡的载流子传输特性, 能够获得高效的磷光发射.     

采用Li3Nn型掺杂层作为电子注入层的OLED器件研究

相对于传统的无机半导体材料,有机半导体材料特别是有机电子传输材料的载流子浓度和迁移率较低,从而影响了有机发光器件的亮度、效率等性能.为了提高有机发光器件器件性能必须增强电子注入和传输能力,对有机电子传输材料进行n型电学掺杂能够有效地提高电子的注入和传输能力.本文利用Li3N作为n型掺杂剂,以掺杂层Alq3:Li3N作为...     

掺杂N的浓度对SiC薄膜的光敏特性影响

在热丝化学汽相沉积（HFCVD）法制备SiC薄膜过程中，研究不同的N掺杂下制备样品的光敏特性．对薄膜在室温和较高温度（410℃）下进行光敏特性测试，结果表明，薄膜的制备工艺参量对其光敏特性有较大影响；较高温度下其敏感特性和室温下测试的结果大体一致；在合适条件下制备的薄膜对不同波长的光有较好的敏感特性．可以看出，SiC薄膜在研究高温光敏器件领域具有很好的应用前景．     

全湿法制备聚合物电致发光器件

利用全溶液方法制备了聚合物电致发光器件并研究了器件的性能。器件的所有膜层,包括发光层和上电极层均采用溶液湿法获得,完全摒弃了真空蒸镀工艺。利用二次溶剂掺杂获得的PEDOT∶PSS聚合物薄膜的电导率达到608.7 S/cm。在240 nm的厚度时,聚合物电极膜层的面电阻约为68 Ω/□; 当膜层厚度为1 μm时,薄膜的面电阻可低于16 Ω/□。采用溶液滴涂方法制备的高电导PEDOT∶PSS聚合物薄膜作为上电极替代通常所用的铝电极,所制备的聚合物发光器件的开启电压约为4 V。     

Random lasing in an organic light‐emitting crystal and its interplay with vertical cavity feedback

The simultaneous vertical‐cavity and random lasing emission properties of a blue‐emitting molecular crystal are investigated. The 1,1,4,4‐tetraphenyl‐1,3‐butadiene samples, grown by physical vapour transport, feature room‐temperature stimulated emission peaked at about 430 nm. Fabry‐Pérot and random resonances are primed by the interfaces of the crystal with external media and by defect scatterers, respectively. The analysis of the resulting lasing spectra evidences the existence of narrow peaks due to both the built‐in vertical Fabry‐Pérot cavity and random lasing in a novel, surface‐emitting configuration and threshold around 500 μJ cm⁻². The anti‐correlation between different modes is also highlighted, due to competition for gain. Molecular crystals with optical gain candidate as promising photonic media inherently supporting multiple lasing mechanisms.     

有机激光材料及器件的研究现状与展望

有机激光器因其制备简单, 价格低廉和易于集成等优势, 一直以来备受科研工作者的关注. 与无机激光介质相比, 有机激光材料来源广泛, 并具有发射光谱宽, 吸收与发射截面积大等特性, 因而有很大的发展潜力. 本文从激光的基本原理出发, 对有机激光材料的种类、特性进行了归纳, 并总结了高效有机激光材料的普遍特征; 分类讨论了常见有机激光微腔的类型与特点, 对有机激光系统内增益与损耗之间的动态关系进行了探讨. 鉴于实现电抽运激光一直以来都是有机激光领域期待解决的难题, 本文重点讨论了当前电抽运有机激光的研究现状和发展瓶颈, 以及科研工作者们对此问题的不懈探索和已有的工作基础. 最后总结了光抽运有机激光近年来的总体进展, 未来的研究方向, 这对于读者拓展新的研究思路有很好的参考和借鉴意义.     

Length dependence of rectification in organic co-oligomer spin rectifiers

The rectification ratio of organic magnetic co-oligomer diodes is investigated theoretically by changing the molecular length. The results reveal two distinct length dependences of the rectification ratio: for a short molecular diode, the chargecurrent rectification changes little with the increase of molecular length, while the spin-current rectification is weakened sharply by the length; for a long molecular diode, both the charge-current and spin-current rectification ratios increase quickly with the length. The two kinds of dependence switch at a specific length accompanied with an inversion of the rectifying direction. The molecular ortibals and spin-resolved transmission analysis indicate that the dominant mechanism of rectification suffers a change at this specific length, that is, from asymmetric shift of molecular eigenlevels to asymmetric spatial localization of wave functions upon the reversal of bias. This work demonstrates a feasible way to control the rectification in organic co-oligomer spin diodes by adjusting the molecular length.     

Organic quantum well and superlattice characteristics in quasi-one-dimensional multiblock copolymers

A tight-binding calculation was presented to describe multiblock copolymers, such as [...-(PA)x-(PPP)y-...] composed of PA (polyacetylene) and PPP (poly(p-phenylene). It is found that a copolymer has a quantum well and superlattice characteristics, and evident is the effect of the composite lengths, the interfacial couplings and the electron-phonon interactions on the electronic properties of a copolymer. The quantum tunneling, the Franz-Keldysh effect and the quantum confinement can be generated under an applied electric field. These results were compared to those of traditional inorganic quantum well and superlattice systems.     

The basis of organic spintronics：Fabrication of organic spin valves

Organic spintronics focuses on utilizing the spin degree of freedom in organic materials because of the long spin relaxation time. The vertical organic spin valve (OSV) is a typical sample structure used to study the spin transport phenomena. However, the fabrication of high quality OSVs is difficult, which results in controversial experiment results and hence hinders the development of organic spintronics. In this work, we describe our recent study on the fabrication of typical vertical organic spin valves, La_0.67Sr_0.33MnO₃ (LSMO)/Alq₃/Co. The LSMO bottom electrodes are annealed to obtain an atomically smooth surface and improved magnetic properties. The top Co electrodes are deposited by an indirect deposition method to reduce the interfusion between Co and Alq3. The controlled fabrication process provides much better performance and sample yield of OSVs.     

Organic single crystal phototransistors: Recent approaches and achievements

Organic phototransistors (OPTs), compared to traditional inorganic counterparts, have attracted a great deal of interest because of their inherent flexibility, light-weight, easy and low-cost fabrication, and are considered as potential candidates for next-generation wearable electronics. Currently, significant advances have been made in OPTs with the development of new organic semiconductors and optimization of device fabrication protocols. Among various types of OPTs, small molecule organic single crystal phototransistors (OSCPTs) standout because of their exciting features, such as long exciton diffusion length and high charge carrier mobility relative to organic thinfilm phototransistors. In this review, a brief introduction to device architectures, working mechanisms and figure of merits for OPTs is presented. We then overview recent approaches employed and achievements made for the development of OSCPTs. Finally, we spotlight potential future directions to tackle the existing challenges in this field and accelerate the advancement of OSCPTs towards practical applications.     

Interfacial processes in small molecule organic solar cells

This paper presents an overview of the recent progress of small molecule organic solar cells mainly based on the previous worksof our group. We will mainly focus on the interfacial processes in the cells. The dissociation of excitons at electrode/organic andorganic/organic interfaces can be directly observed by transient photovoltage measurements. A simple model including dissociationof excitons at the interface and drift of free carriers in the built-in field is proposed to explain the observed signals of ...     

可降解有机物湿解实验研究

选用杂草作为城市生活垃圾中可降解有机物的典型组分,研究了湿解参数对湿解后固体、气体和液体比例的影响,以及固体成分中有机质、黄腐酸、胡敏酸和大量营养元素的影响。结果表明,湿解应采用适当的高温和短的反应时间,如在 480 K 下湿解 0.25 h,固体成分保留最多,有机质含量最丰富,腐殖化程度最高,但大量营养元素的含量也最低。     

吩基吡啶铍(Bepp2)配合物的高效蓝光器件

高荧光的吩基吡啶铍(Bepp2)作为发射层构成高效蓝色电致发光器件.这一由空穴注入层、空穴传输层、Bepp2发射层组成的多层器件,使用一电子传输层以获得高性能.这种器件结构,最大亮度达6 200cd·m-2、电致发光效率1.3 cd/A(0.71 lm/W),吩基吡啶铍(Bepp2)的电致发光光谱峰值在451 nm.这些初步的结果表明配合物铍应用于电致发光是非常有前景的材料.在化学方面的进一步考察和新的羟苯基吡啶金属配合物电致发光器件的优化也在进行中.     

Structure design for high performance n-type polymer thermoelectric materials

Organic thermoelectric(OTE)materials have been regarded as a potential candidate to harvest waste heat from complex,low temperature surfaces of objects and convert it into electricity.Recently,n-type conjugated polymers as organic thermoelectric materials have aroused intensive research in order to improve their performance to match up with their ptype counterpart.In this review,we discuss aspects that affect the performance of n-type OTEs,and further focus on the effect of planarity of backbone on the doping efficiency and eventually the TE performance.We then summarize strategies such as implementing rigid n-type polymer backbone or modifying conventional polymer building blocks for more planar conformation.In the outlook part,we conclude forementioned devotions and point out new possibility that may promote the future development of this field.