Enhanced Efficiency of Polymer： Fullerene Bulk Heterojunction Solar Cells with the Insertion of Thin TiO2 Layer near the LiF/A1 Electrode

The insertion layer of TiO2 between polymer-fullerene blend and LiF/AI electrode is used to enhance the shortcircuit current Isc and fill factor （FF）. The solar cell based on the blend of poly[2-methoxy-5-（2＇-ethylhexyloxy）- 1,4-phenylenevinylene] （MEH-PPV） and C60 with the modifying layer of TiO2 （about 20nm） shows the open- circuit Voc of about 0.62 V, short circuit current Isc of about 2.35 mA/cm^2, filling factor FF of about 0.284, and the power conversion efficiency （PCE） of about 2.4% under monochromatic light （50Onto） photoexcitation of about 17mW/cm^2. Compared to ceils without the TiO2 layer, the power conversion efficiency increases by about 17.5%. Similar effect is also obtained in cells with the undoped MEH-PPV structure of ITO/PEDOT：PASS/MEH- PPV/（TiO2）LiF/AI. The improved solar cell performance can be attributed to enhanced carrier extraction efficiency at the active layer/electrode interfaces when TiO2 is inserted.     

Effect of TiO2 Nanotubes on Polymer-Fullerene Bulk Heterojunction Solar Cells

We investigate the photovoltaic properties of hybrid organ/c solar cell based on the blend of poly[2-methoxy-5-（2- ethylhexoxy-l,4-phenylenevinylene） （MEH-PPV）, C60 and titanium dioxide （TiO2） nanotubes. In comparison of the composite devices with different TiO2：[MEH-PPV ＋C60] weight ratios of lw$.% （D1-1）, 2wt.% （D1-2）, 3wt.% （D1-3）, 5wt.% （D1-4）, 10wt.% （D1-5） and 20wt.% （D1-6）, it is found that the device Dl-a exhibits the best performance. The conversion efficiency is improved by a factor of 3 compared with the MEH-PPV：C60 device.     

TFTTP作为阴极缓冲层提高有机薄膜太阳能电池的内建电场和载流子收集效率

采用一种新型的电子传输材料TFTTP作为阴极缓冲层提高基于SubPc/C₆₀异质结的有机薄膜太阳能电池的性能. 通过在有机活性层和金属电极之间加入TFTTP界面层,器件的能量转换效率提高了约30%. 系统研究了器件的二极管特性、光电流特性以及内部的光场分布情况,结果表明,TFTTP阴极缓冲层的引入可以有效地提高器件的内建电场,进而增加电荷转移激子的分离效率. 通过使用TFTTP作为阴极缓冲层,在C₆₀/金属界面形成良好的欧姆接触,降低了界面接触电阻,有利于自由载流子的收集.     

Properties of C60 thin film transistor based on polystyrene

This paper reports that the n-type organic thin-film transistors have been fabricated by using C60 as the active layer and polystyrene as the dielectric.The properties of insulator and the growth characteristic of C60 film were carefully investigated.By choosing different source/drain electrodes,a device with good performance can be obtained.The highest electron field effect mobility about 1.15 cm 2 /(V·s) could reach when Barium was introduced as electrodes.Moreover,the C60 transistor shows a negligible 'hysteresis effect' contributed to the hydroxyl-free of insulator.The result suggests that polymer dielectrics are promising in applications among n-type organic transistors.     

Interaction between B-Doped C60 Fullerene and Glycine Amino Acid from First-Principles Simulation

The possibility of formation of complexes between glycine and boron doped C60 （C59B） fullerene is investigated and compared with that of C60 fullerene by using the density functional theory calculations. It has been found that the binding of glycine to C59B generated the most stable complexes via its carbonyl oxygen active site, with a binding energy of-37.89 kcal/mol, while the glycine molecule prefers to bind to the pure C60 cage via its amino nitrogen active site, consistent with the recent experimental and theoretical studies. We have also tested the stability of the most stable Gly-C59B complex with ab initio molecular dynamics simulation, carried out at room temperature. These indicate that the B-doped C60 fullerenes seem to be more suitable materials for bindings to proteins than pure C60 fullerenes.     

Dynamics of excitons and carriers at the NPB/C60 interface by transient photocurrents

The transient photocurrent (TPC) technique was performed to explore the dynamics of excitons and carriers at organic active layer/buffer layer interfaces. A special device with ITO/PEIE/NPB/C₆₀/Al structure was designed to study the interfacial processes at the NPB/C₆₀ interface. An external electrical field was provided to neutralize the built-in electrical field of the device. Interestingly, a new phenomenon was observed, wherein the polarity of the TPC changed from negative to positive under an external electrical field. The initial negative signal was ascribed to exciton separation by the built-in field in C₆₀, and the subsequent positive signal can be attributed to the diffusion of electrons that accumulate at the NPB/C₆₀ interface. TPC measurements shown that further increasing the external electrical field causes polarity to change twice. Analyzing the two changes in polarity revealed that the NPB did not only extract holes from C₆₀ but also provided an effective interface for exciton dissociation.     

Organic light-emitting devices obtained with helium-ion-beam-assisted deposition process

Until now, the organic light-emitting diode (OLED) has consisted of a luminescent electron transport layer (Alq3 in our case) and a hole transport layer (HTL) such as TPD (obtained in a chemical way) which differs from the luminescent layer. In this paper, we report results where the HTL layer is also the luminescent layer (Alq3) modified by a physical way: the ion-beam-assisted deposition (IBAD). With helium ions, which are inactive ions with a small size, we determine the ion-beam parameters to optimize the OLED optoelectronic parameters: ion-beam energy E_i=100 eV, ion-beam current density J_i=100 nA/cm², speed of deposition v_dep=0.41 nm/s. With these ion-beam parameters and only an ion-beam assistance of the Alq3 layer located on the anode side, we obtain a twentyfold improvement in efficiency.     

4,4′,4″-三(N-3-甲基苯基-N-苯基氨基)三苯胺掺杂MoOx作为空穴传输层对有机太阳电池性能的影响

通过采用4,4′,4″-三(N-3-甲基苯基-N-苯基氨基)三苯胺 (m-MTDATA)掺入MoO_x作为器件的空穴传输层来提高酞菁铜(CuPc)/C₆₀小分子 有机太阳电池的效率. 采用真空蒸镀的方法制备了一系列器件, 其中结构为铟锡氧化物 (ITO)/m-MTDATA:MoO_x(3:1)(30 nm)/CuPc(20 nm)/C₆₀(40 nm)/4,7-二苯 基-1,10-菲罗啉 (Bphen)(8 nm)/LiF(0.8 nm)/Al(100 nm)的器件, 在AM1.5 (100 mW/cm²)模拟太阳光的照射条件下, 开路电压V_oc=0.40 V, 短路电流J_sc=6.59 mA/cm², 填充因子为0.55, 光电转换效率达1.46%, 比没有空穴传输层的器件ITO/CuPc(20 nm)/C₆₀(40 nm)/Bphen(8 nm)/LiF(0.8 nm)/Al(100 nm) 光电转换效率提高了38%. 研究表明, 加入m-MTDATA:MoO_x(3:1)(30 nm)空穴传输层减小了有机层和ITO电极之间的接触电阻, 从而减小了整个器件的串联电阻, 提高了器件的光电转换效率.     

Ultraviolet Photoelectron Spectroscopy of Fullerenes C60 and C70:A Model Study

Geometrical optimizations of two fullerenes, C₆₀ and C₇₀, have been performed by means of density-functional theory techniques. Based on the Gelius model, ultraviolet photoelectron spectra (UPS) of C₆₀ and C₇₀ have been simulated. We have shown how the different local arrangements of carbon atoms of C₇₀ are responsible for the spectra. Our calculated spectra are in good agreement with the experimental counterparts.     

Organic Light Emitting Diodes Using Doped Alq3 as the Hole-transport Layer

Effects of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane （F4TCNQ） doping on the hole conductivity of Alq3 layer are measured. In the hole-only device of Alq3, the current densities increase in 1-3 orders of magnitude upon doping with F4TCNQ, suggesting that the doping can effectively enhance the hole-injection and hole- transport ability of Alq3. An organic light-emitting device using an F4TCNQ doped Alq3 layer as the hole- injection and hole-transport layer, and pristine Alq3 as the electron-transport and emitting layer is fabricated and characterized. Bright emission is achieved in the simple OLED with p-doped Alq3 as the hole-transport layer and the intrinsic Alq3 as the electron-transport and emitting layer. The emitting efficiency and brightness of the device are further improved by inserting a thin electron block layer to confine the carrier recombination zone in the middle of the organic layers.     

Carbon Nanoparticles in Nematic Liquid Crystals

Fullerene C60, C7o, single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal （LC） host in the same percentage. Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications. Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules, while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.     

Mass spectroscopic and degassing characteristics of polymeric materials for 157 nm photolithography

We report on the mass spectroscopic and the degassing characteristics of an epoxy novolac-based chemically amplified photoresist, with triphenylsulfonium hexafluoroantimonate as photoacid generator, using an F₂ pulsed discharge molecular laser at 157 nm. This photoresist has been used previously for optical (248 nm), e-beam, and X-ray microlithography both in wet and dry development processes. For laser energy of 1 mJ per pulse focused on the sample and 5 MW/cm² intensity, photofragments with m/e less than 40 amu have a higher probability of formation. These fragments are mainly attributed to the breaking of the substituents of the aromatic rings. The specific fragments observed are: H, H₂, C, CH, CH₂, CH₃, O, OH, H₂O, HF, C₂, C₂H, C₂H₂, C₂H₃, CO, C₂H₄, C₂H₅, C₂H₆, H₂CO, OCH₃, O₂, C₃H₃, C₃H₄, C₃H₅, C₃H₆, C₃H₇, C₂H₃O, C₃H₈, C₂H₅O, C₃O, C₃HO, C₃H₂O, C₃H₃O, C₃H₄O, C₃H₅O, C₂HO₂, C₂H₂O₂, C₂H₃O₂, C₂H₄O₂, C₂H₅O₂ and C₂H₆O₂. Comparison of these results with the ones obtained from samples with pure epoxy novolac polymer show that the direct fragmentation of the side polymer bonds is predominant over bond breaking arising from the presence of the triphenylsulfonium salt sensitizer.     

Influence of Dopant Concentration on Electroluminescent Performance of Organic White-Light-Emitting Device with Double-Emissive-Layered Structure

A novel phosphorescent organic white-light-emitting device （WOLED） with contiguration of ITO/NPB/CBP： TBPe：rubrene/Zn（BTZ）2：Ir（piq）2（acac）/Zn（BTZ）2/Mg：Ag is fabricated successfully, where the phosphorescent dye bis （1-（phenyl）isoquinoline） iridium （Ⅲ） acetylanetonate （Ir（piq）2 （acac）） doped into bis-（2-（2-hydroxyphenyl） benzothiazole）zinc （Zn（BTZ）2） （greenish-blue emitting material with electron transport character） as the red emitting layer, and fluorescent dye 2,5,8,11-tetra-tertbutylperylene （TBPe） and 5,6,11,12-tetraphenyl-naphthacene （rubrene） together doped into 4,4＇-N,N＇-dicarbazole-biphenyl （CBP） （ambipolar conductivity material） as the blue-orange emitting layer, respectively. The two emitting layers are sandwiched between the hole-transport layer N ,N＇-biphenyl-N , N＇-bis （1-naph thyl）-（1,1＇-biphenyl）-4, 4 Cdiamine （NP B） and electron-transport layer （Zn（BTZ）2 ） The optimum device turns on at the driving voltage of 4.5 V. A maximum external quantum efficiency of 1.53%. and brightness 15000 cd/m^2 are presented. The best point of the Commission Internationale de 1＇Eclairage （CIE） coordinates locates at （0.335, 0.338） at about 13 V. Moreover, we also discuss how to achieve the bright pure white light through optimizing the doping concentration of each dye from the viewpoint of energy transfer process.     

基于光学与光—电转换模型对聚合物电池功能层厚度与性能相关性分析

本文基于Forouhi-Bloomer 模型得到了这种功能层的光学常数.根据菲涅耳系数矩阵法计算了这种器件内的光电场分布,并计算了不同厚度的聚合物功能层的光子吸收数.同时,通过Onsager-Braun理论,分析了在无外加电场下聚合物功能层厚度对激子分离概率的影响.理论分析和实验结果证明:在特定的薄膜制备工艺下,器件结构为ITO/PEDOT/ P3HT:PC₆₀BM /LiF/Al时,聚合物功能层厚度在100 nm左右时,可以使器件的光子吸收数最大化,同时避免了激子分离概率的降低. 关键词： 光学常数 激子 聚合物太阳能电池     

A comparative study of electrode effects on the electrical and luminescent characteristics of Alq3/TPD OLED: Improvements due to conductive polymer (PEDOT) anode

The performance of organic light emitting device (OLED) structures, based on identically fabricated Alq₃/TPD active regions, with various anode and cathode electrode structures are compared, and performance differences related to the different anode structure. The best performance was achieved with a conductive polymer, 3,4-polyethylenedioxythiopene-polystyrenesultonate (PEDOT), used as an anode layer, yielding a brightness of 1720 cd/m² at 25 V, a turn-on voltage of 3 V, and electroluminescence (EL) efficiency and external quantum efficiency of 8.2 cd/A and 2%, respectively, at a brightness of 100 cd/m² and 5 V. Compared to a baseline device (TPD/Alq₃/Al), PEDOT anodes substantially reduce the turn-on voltage and made current injection almost linear after turn-on, whiles devices incorporating a LiF and CuPc layers significantly improved device efficiency while slightly improving turn-on voltage and maintaining superlinear I-V injection. This is attributed to the reduced barrier at the organic-organic interface in PEDOT, the ‘ladder’ effect of stepping the band offset over several interfaces, and the favorable PEDOT film morphology. The benefit of the PEDOT anode is clearly seen in the improvement in device brightness and the high external quantum efficiency obtained.     

利用混合有机空穴传输材料提升有机薄膜晶体管场效应迁移率

通过采用在并五苯薄膜与源漏电极之间插入10 nm 并五苯掺杂的N,N’-二苯基-N,N’-二（3-甲基苯基）-1,1’-联苯-4,4’-二胺薄膜的方法研究了基于并五苯有源层的底栅错面型有机薄膜晶体管的电学特性。研究发现：N,N’-二苯基-N,N’-二（3-甲基苯基）-1,1’-联苯-4,4’-二胺的引入可以有效改善有源层和源漏电极接触界面的表面形貌,利于形成欧姆接触,从而改善器件性能,最终使优化器件的迁移率由（0.1±0.01）cm²/（V·s）提升至（0.31±0.02）cm²/（V·s）,阈值电压由（－34.6±1.3）V 降至（－30.1±1.2）V。     

Mass spectroscopy and ablation characteristics of nylon 6.6 in the ultraviolet

We report on the mass spectroscopic and the laser ablative characteristics of nylon 6.6 [-NH-(CH₂)₆-NH-CO-(-CH₂)₄-CO-] at 193 and 248 nm, using the ArF and KrF excimer lasers. The characteristic parameters of the laser ablative process, such as etch rate at different fluences, the threshold fluence, and the absorption coefficient for both wavelengths were determined. Even at low laser energy, there was a complete breaking of the polymeric chain bonds. The following photofragments were observed at 248 nm: H, H₂, C, CH, CH₂, N, NH, O, OH, H₂O, C₂H, C₂H₂, CN, C₂H₃, HCN, N₂, CO, C₂H₄, COH, C₂H₅, N₂H, NO, C₂H₆, H₂CO, N₂H₂, C₂, CH₂NH, O₂, C₃H₃, C₃H₄, C₃H₅, C₃H₆, CNO, HCNO, and H₂CNO. At 193 nm no photofragments were observed for m/e larger than 30 amu. The photofragments with two carbon atoms have a relatively higher probability to be dissociated from the parent monomer, than heavier photofragments with four carbon atoms. The mass spectroscopic studies and the absorption spectrum of nylon 6.6 in the ultraviolet, suggest photochemical bond-breaking at 248 and 193 nm. The monomer dissociates into fragments with the predominant mass at 28 amu for both laser wavelengths. Therefore the amide group is mainly involved in the photodissociation process of nylon 6.6 in the ultraviolet. The experimental results suggest that the photochemical dissociation of the polymeric chain is the dominant mechanism of the laser ablation of nylon 6.6 at 193 and 248 nm.     

Significant improvement of OLED efficiency and stability by doping both HTL and ETL with different dopant in heterojunction of polymer/small-molecules

This paper reports that the polymer/organic heterojunction doped light-emitting diodes using a novel poly-TPD as hole transport material and doping both hole transport layer and emitter layer with the highly fluorescent rubrene and DCJTB has been successfully fabricated. The basic structure of the heterostructure is PTPD/Alq₃. When hole transport layer and electron transport layer are doped simultaneously with different dopant, the electroluminescence quantum efficiencies are about 3 times greater than that of the undoped device. Compared with undoped device and conventional TPD/Alq₃ diode, the stability of the doping device is significantly improved. The process of emission for doped device may include carrier trapping as well as F\"{o}rster energy transfer.     

基于智能剥离技术的SOI材料制备

优化了硅片低温直接键合与智能剥离技术的工艺流程，在550℃，2.1×10^-2 Pa条件下制备了SOI材料，其顶层单晶Si膜的表面粗糙度为8.5 nm，缺陷密度为90 cm^-2，键合强度达到153.7 kg/cm²，形成的SOI结构除了可以形成三维集成电路中有源层间良好的绝缘层，避免了高温过程对有源层器件结构、材料及性能的影响，还能为三维集成电路后续有源层的制造提供高质量的单晶硅材料. 关键词： 绝缘体上硅 智能剥离 低温直接键合     

利用不同阴极缓冲层来改善Pentacene/C60太阳能电池的性能

制备了结构为ITO/Pentacene/C₆₀/Al的双层光伏电池器件,在C₆₀/Al界面插入了常用的缓冲层材料bathocuproine(BCP)作为阴极缓冲层,通过优化BCP层的厚度来提高电池的性能并研究了阴极缓冲层的作用机理.实验发现,BCP厚度为10 nm时器件的效率最高,为0.46%.在此基础上,利用bathophenanthroline(Bphen)和3,4,9,10-Perylenetetracarb-oxylicdianhydride(PTCDA 关键词： 有机太阳能电池 Pentacene 60')" href="#">C₆₀ 缓冲层