TiO_2/SrTiO_3薄膜电极制备及其光电化学性能研究

采用商用P25TiO2为原料制备纳米多孔TiO2电极,用水热法在多孔TiO2表面包覆SrTiO3。采用X射线衍射仪、扫描电子显微镜及紫外-可见光谱仪对TiO2/SrTiO3薄膜电极进行表征。探讨了水热反应温度对TiO2/SrTiO3薄膜电极组装染料敏化太阳能电池(DSSC)的光电化学性能影响。结果表明:在纳米多孔TiO2电极表面生成了均匀的SrTiO3包覆层,且SrTiO3包覆的样品吸收边有红移;与TiO2薄膜电极相比,不同水热反应温度下制备的TiO2/SrTiO3薄膜电极组装DSSC的光电转换效率均有所提高,180℃时全光转换效率提高了24%。     

Highly efficient ITO-free polymer solar cells based on metal resonant microcavity using WO3/Au/WO3 as transparent electrodes

Indium tin oxide (ITO)-free polymer solar cells (PSCs) with the structure of Glass/tungsten trioxide (WO₃)/Au/WO₃/PCDTBT: PC₇₀BM/LiF/Al was fabricated and studied. The multilayer structure of WO₃/Au/WO₃ is used as the potential transparent electrode to replace ITO. Metal resonant microcavity, which can enhance light harvesting of active layers, was constructed between Au and Al electrodes. According to the J–V and IPCE characterization with 70 nm active layer, power conversion efficiency (PCE) of the ITO-free microcavity device is approaching 4.55%, which is higher than that of the ITO-based device. However, PCE of the ITO-free device is much lower than that of the ITO-based device when the thickness of active layer increases to 130 nm. The opposite experimental tendency leads to theoretical research toward the simulation of light absorption and optical electric field and the calculation of maximum short circuit current density (J_{sc max}) as a function of active layer thickness based on ITO-free and ITO-based devices. The research results show that microcavity effect is closely linked to intrinsic absorption of active layers.     

Transparent Al/WO3/Au film as anode for high efficiency organic light-emitting diodes

A transparent Al/WO₃/Au anode is introduced to fabricate high efficiency organic light-emitting devices (OLEDs). By optimizing the thicknesses of each layers of the Al/WO₃/Au structure, the transmittance of Al(7 nm)/WO₃(3 nm)/Au(13 nm) has reached over 55%. Concerning the performance of OLEDs using the optimized anode, the electroluminescence (EL) current efficiency and brightness are enhanced and the EL spectrum is greatly narrowed as compared to the OLEDs using indium-tin-oxide (ITO) as the anode. The results indicate that the metal/metal oxide/metal transparent electrode is a good structure for the anode of high performance OLEDs. In addition, Al/WO₃/Au can function as a composite transparent electrode for top-emitting OLEDs.     

Au薄膜溅射功率对ZnO/Au复合薄膜质量的影响

在ZnO薄膜上采用不同溅射功率制作了Au薄膜,研究不同溅射功率对Au膜成膜速率、结晶质量和结合力的影响,表明在本实验中100 W功率下Au膜的成膜质量比较好。同时对ZnO薄膜电阻的影响进行了研究,结果表明溅射功率越高,ZnO导通的可能性越大,通过实验,溅射工艺在100 W下制备的Au薄膜对ZnO电阻影响最小。     

Fabrication of Au/PEDOT stacked electrodes for organic thin film transistors by imprinting technology

In this work, the Au/PEDOT stacked source/drain electrodes of OTFTs were fabricated by combining the micro-contact inking and reversal imprinting. The PEDOT was inked on the mold by the micro-contact process and the Au/PEDOT stacked layer was transferred on pentacene by imprinting technology. The threshold voltage, and on-off ratio, carrier mobility, and source/drain contact resistance of organic TFTs were all improved by the proposed process.     

基于钯金复合膜亚波长圆孔阵列的氢气传感器的理论研究

提出了一种基于钯金(Pd/Au)复合膜的亚波长圆孔阵列结构的氢气传感模型,用于氢气泄漏及氢气浓度检测。利用时域有限差分法(finite-difference time-domain, FDTD)对该Pd/Au复合膜亚波长圆孔阵列结构进行模拟仿真,计算其复合膜的横纵截面电场能量分布及透射特性,并进一步分析在不同结构参数下该传感结构的异常光 透射(extraordinary optical transmission,EOT) 特性和传感特性。模拟结果表明:Pd/Au复合膜亚波长圆孔阵列结构可产生明显的EOT效应,形成两个突出的异常透射峰,记作峰Ⅰ、峰Ⅱ。当通入氢气时,钯(Pd)膜会吸收氢气引起Pd介电常数的变化,导致EOT特性发生改变,具体表现为波长和透射率的改变。氢气浓度由0%上升至4%时,峰Ⅰ和峰Ⅱ的透射率变化量分别可达到0.16和0.24。由于其透射率强度变化比较明显,因此可通过透射峰强度变化来实现对氢气浓度的监控和检测。本文所提出的基于Pd/Au复合膜的亚波长圆孔阵列结构的氢气传感器的圆孔结构加工简单,所镀的Pd膜很薄使传感器响应速度快,EOT效应使该结构信噪比(signal-to-noise ratio,SNR) 高,可利用光电集成技术进行批量生产,具有很强的实用价值。     

采用氧化物复合底电极的BTO薄膜结构和性能

用球磨法制备Bi4Ti3O1(2BTO)靶材。用PLD法在Pt/TiO2/SiO2/Si基片上先分别以三种氧化物SrRuO(3SRO)、LaSrCoO3(LSCO)、LaNiO3(LNO)和Pt生成复合底电极,再在其上生长了外延取向的BTO薄膜。分析了薄膜的结构和性能。结果表明,这种BTO薄膜的c轴取向得到抑制,其极化强度从0.45×10–6C/cm2提高到0.9×10–6C/cm2;矫顽场强从90×103V/cm下降到50×103V/cm。     

陶瓷基片表面Au/电阻复合厚膜烧结起泡及其消除

针对以国内新研发的Au导体浆料与电阻浆料在Al_2O_3基片表面印制的Au导体/电阻复合厚膜烧结易起泡的现象,在探明起泡原因的基础上,研究了烧结温度、升温速率以及Au层厚度对复合厚膜起泡的影响,进一步优化厚膜工艺,制备出无起泡的复合厚膜。研究表明,烧成温度过高导致的玻璃相浮于复合膜层表面并结晶,烧结过程不充分和Au层厚度不足等导致不能在陶瓷基片/Au层界面形成连续的玻璃相粘结层,界面结合强度大大降低,在陶瓷基片/Au层界面易起泡。在烧结峰值温度为825℃,升温速率为40℃/min,Au导体层厚度为10μm的工艺条件下,复合厚膜与陶瓷基片结合紧密,无起泡现象。     

电沉积三氧化钨薄膜电致变色及其光电化学性能

电沉积ＷＯ３薄膜显示出可逆光致变色及电致变色行为（在红外区域附近具有蓝色光吸收）。通过Ｘ射线光电子能谱（ＸＰＳ），对ＷＯ３薄膜在不同呈色水平上的Ｗ４ｆ核能级作了观察研究，可见Ｗ４ｆ核能级在ＷＯ３膜显色后变宽，光电化学测定表明ＷＯ３薄膜具有低光电转换效率。     

GaN MSM photodetectors with photo-CVD annealed Ni/Au electrodes

Thin Ni/Au (3/6 nm) bi-layer metal films annealed by photo-chemical vapor deposition (photo-CVD) were investigated. With proper annealing in oxygen by the photo-CVD systems, it was found that the transmittance of the deposited Ni/Au increased from 67 to 85% in the region between 350 and 450 nm. GaN metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors with photo-CVD annealed Ni/Au contact electrodes were also fabricated. It was found that dark current of the detector became significantly smaller after annealing. With a 1 V applied bias, it was found that we can achieve a photocurrent to dark current contrast ratio of 2.54×10³ from the photodetectors with 600 °C photo-CVD annealed Ni/Au contacts.     

Buffer and anode-integrated WO3-doped In2O3 electrodes for PEDOT:PSS-free organic photovoltaics

We developed PEDOT:PSS-free organic solar cells (OSCs) using WO₃ and In₂O₃ (IWO) mixed electrodes acting as a buffer hole injection layer (HIL) and anode simultaneously. Through the co-sputtering and rapid thermal annealing (RTA) of WO₃ and In₂O₃, we achieved buffer and anode-integrated transparent electrodes with a sheet resistance of 17 Ohm/square, a transmittance of 90.32%, and a work function of 4.83 eV, all of which are comparable to values obtained with a conventional ITO anode. Due to the existence of WO₃ in the In₂O₃ matrix, OSCs fabricated on an IWO electrode with no acidic PEDOT:PSS buffer layer showed a PCE of 2.87%. Therefore, a transparent IWO electrode simultaneously acting as an HIL and anode layer can be considered a promising transparent electrode for cost-efficient and reliable OSCs because it could eliminate the use of acidic PEDOT:PSS buffer layer.     

高介电常数Ta/Al2O3复合膜的制备及性能研究

首次在溴的丙酮溶液中,以钽为阳极,氧化铝为阴极,通过直流电沉积方法制备了Ta/Al_2O_3复合膜。借助LCR数字电桥、SEM、EDS等测试手段对Ta/Al_2O_3复合膜的介电性能及微观结构进行了分析与表征。研究表明:Ta/Al_2O_3复合氧化膜的表面沉积了质量分数为41.77%的钽。与普通铝阳极(Al_2O_3)氧化膜相比,复合氧化膜的电容提高了50%以上,这主要归因于介电常数较高的钽在复合氧化膜表面的沉积。     

ITO-free,efficient, and inverted phosphorescent organic light-emitting diodes using a WO3/Ag/WO3 multilayer electrode

We present an indium tin oxide (ITO)-free, bottom-emission inverted phosphorescent organic light-emitting diode (PHOLED) with a maximum luminance of 280,000 cd/m² at 8 V, total maximum current efficiency of 81.4 cd/A, and external quantum efficiency of 22.4%. The inverted OLED structure is composed of glass/WO₃ (30 nm)/Ag (15 nm)/WO₃ (5 nm)/BPhen:15wt% CS₂CO₃ (5 nm)/BPhen (30 nm)/CBP: 8wt% Ir(ppy)₃ (10 nm)/TAPC (50 nm)/WO₃ (5 nm)/Ag (150 nm) multilayers. In this device structure, the WO₃/Ag/WO₃ (WAW) multilayer serving as a transparent cathode demonstrates a low sheet resistance (3.5 Ω/sq) and high optical transmittance (approximately 80%) in a visible light range of 400–600 nm; this multilayer was prepared by thermal evaporation to form a relatively smooth morphology of the conductive thin film on the glass substrate. In addition, an electron-only WAW device was subjected to electrical characterization, and the results revealed that this device exhibited a more efficient electron injection property at the WAW/BPhen:CS₂CO₃ interface than the contact electrode of a standard ITO-based device.     

纳米WO_3/聚苯胺复合材料的制备及气敏性能

用过硫酸铵作为氧化剂,通过界面聚合法制备纳米聚苯胺,并进一步通过水热法制备了纳米WO3/聚苯胺复合材料。通过XRD、FTIR、TG-DTA、SEM等手段对不同聚苯胺掺杂(质量分数为1%,5%,10%)的WO3/聚苯胺复合材料进行了表征,并进行了气敏性能研究。结果显示,合成的球状纳米WO3包覆棒状聚苯胺核-壳结构复合材料主晶相为正交晶系,晶粒大小约为20 nm;掺杂质量分数10%的聚苯胺后,主晶相变为六方晶系,晶粒大小为15 nm左右。复合材料的分解温度提高到262℃左右。气敏性能研究表明,复合材料在室温对三甲胺显示出较好的气敏性能,对体积分数200×10–6的三甲胺的灵敏度达到4.8。     

聚噻吩/WO3复合纳米材料的制备及气敏性能

采用水合肼法制备WO3粉体,再以无水FeCl3作氧化剂,通过原位化学氧化聚合制备了不同聚噻吩(PTh)掺杂量的PTh/WO3复合纳米材料。并研究了用其制备的气敏元件的气敏性能。结果表明:气敏元件对H2S和NOx有较高的灵敏度和较好的选择性。用质量分数w(PTh)为5%的PTh/WO3复合纳米材料制备的气敏元件,在加热电压为2.25V时,对体积分数φ(NOx)为5×10–6的灵敏度可达77.14;用w(PTh)为20%的PTh/WO3复合纳米材料所制之气敏元件,在加热电压为2.43V时,对φ(H2S)为20×10–6的灵敏度达63.27。     

仿生合成CoO/Co/C复合电极材料及其超级电容性能研究

以松木作为生物模板和碳源,以Co(NO_3)_2·6H_2O作为钴源,煅烧制备多孔CoO/Co/C复合电极材料。通过X-射线衍射(XRD),扫描电子显微镜(SEM),N_2等温吸附-脱附(BET)对复合材料的结构和形貌进行表征。结果表明,复合电极材料遗传了木材模板的生物形貌特点和多级孔道结构,BET表面积为369.2 m~2/g。CoO/Co/C电极具有较好的电化学性能,在1 A/g电流密度下比电容达760 F/g,在电流密度5 A/g下循环充放电500次后,电容保持率为73.7%。     

ZnO/Ag 纳米线复合薄膜的光电导型紫外探测器

ZnO/Ag纳米线复合薄膜紫外探测器是利用水热法在旋涂制备的Ag纳米线薄膜上生长ZnO 纳米线阵列制备得到。此紫外探测器在4.9 mW cm_-2紫外光强和1V偏压下,其明暗电流比为3100,响应恢复时间分别为3.47s和3.28s,响应度为0.25A/W,探测度为6.9×10₁₂Jones。制备和工作参数被分析以优化紫外探测器结构和性能,如ZnO 纳米线的生长时间,Ag纳米线薄膜的旋涂转速和紫外探测器的工作温度。     

GaInN/GaN solar cells made without p-type material using oxidized Ni/Au Schottky electrodes

GaInN/GaN solar cells made without p-type material are demonstrated using an oxidized Ni/Au Schottky barrier design to collect photo-generated carriers. The best devices exhibit a short-circuit current density of 0.065 mA/cm² with an open-circuit voltage of 0.4 V under AM0 (1-Sun) illumination. Preliminary computer simulations are in reasonable agreement with experimental results, giving a pathway to improve device performance via iterative redesign and testing.     

CNT/PDMS composite flexible dry electrodes for long-term ECG monitoring

We fabricated a carbon nanotube (CNT)/ polydimethylsiloxane (PDMS) composite-based dry ECG electrode that can be readily connected to conventional ECG devices, and showed its long-term wearable monitoring capability and robustness to motion and sweat. While the dispersion of CNTs in PDMS is challenging, we optimized the process to disperse untreated CNTs within PDMS by mechanical force only. The electrical and mechanical characteristics of the CNT/PDMS electrode were tested according to the concentration of CNTs and its thickness. The performances of ECG electrodes were evaluated by using 36 types of electrodes which were fabricated with different concentrations of CNTs, and with a differing diameter and thickness. The ECG signals were obtained by using electrodes of diverse sizes to observe the effects of motion and sweat, and the proposed electrode was shown to be robust to both factors. The CNT concentration and diameter of the electrodes were critical parameters in obtaining high-quality ECG signals. The electrode was shown to be biocompatible from the cytotoxicity test. A seven-day continuous wearability test showed that the quality of the ECG signal did not degrade over time, and skin reactions such as itching or erythema were not observed. This electrode could be used for the long-term measurement of other electrical biosignals for ubiquitous health monitoring including EMG, EEG, and ERG.