共查询到19条相似文献,搜索用时 140 毫秒
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叙述了多碱光电阴极光谱反射的特点,测量了超二代微光像增强器多碱光电阴极的光谱反射曲线,分析了光谱响应曲线产生干涉加强峰和干涉减弱峰的原因,比较了不同膜层厚度多碱阴极光谱反射曲线的区别.根据能量守恒定律,利用实测的多碱光电阴极光谱反射率和光谱透过率,计算出多碱光电阴极的光谱吸收曲线,通过研究不同厚度多碱阴极的光谱吸收,发现多碱光电阴极膜层厚度加厚并不会提高其对所有波段光吸收率的特点.厚度增加只会增加短波和长波的光吸收率,但中波的光吸收率不会增加反而下降,这是由于受到光谱反射的影响.阴极膜层的厚度既影响光谱反射和光谱透过,又会影响光谱吸收,因此也影响多碱阴极的光谱响应,所以多碱光电阴极的膜层厚度是影响多碱光电阴极灵敏度的一个关键参数.实践证明,转移式技术制作的多碱光电阴极膜层厚度也存在一个最佳值,超过这一最佳厚度,阴极的灵敏度不增反降,这是因为红外光谱响应增加不多,但中波光谱响应下降很多.所以对转移式多碱光电阴极而言,实践证明当膜层厚度达到最佳厚度时,膜层呈现淡红色,在制作过程中要控制好阴极膜层的厚度,这样才可能获得较高的阴极灵敏度. 相似文献
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通过将聚乙二醇(PEG)掺入活性层制备聚合物太阳 能电池,利用PEG的迁移特性获得阴极修饰层,研 究PEG阴极修饰层对聚合物太阳能电池光电性能的影响。X射线光电子能谱(XPS)分 析表明,掺入活性层中的 PEG迁移到活性层与Al电极之间,形成了阴极缓冲层。吸收光谱、电流密度-电压 特性曲线和外量子 效率谱的分析表明,PEG阴极缓冲层的形成改善了活性层与阴极的界面接触特性, 降低了活性层与电 极之间的能级势垒,有利于载流子传输,因此显著地改善了聚合物太阳能电池的光电性能, 使得器件的开 路电压Voc、短路电流密度Jsc和填充因子(FF)都有明显提高。当P3HT:PCBM 活性层中掺入体积比为0.5%的PEG时,聚合物太阳能电池的能量转换 效率(P CE)最高,达到了3.07%,比未掺杂PEG的参考器件提 高了38.5%。 相似文献
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利用金属有机物化学气相沉积技术在蓝宝石衬底上异质外延生长了GaN光电发射层,为降低GaN发射层和蓝宝石衬底间的晶格失配与热失配,在蓝宝石衬底和GaN发射层间分别采用了AlN和AlxGa1-xN两种不同的缓冲层材料。对具有不同缓冲层材料的两种样品进行了表面清洗与激活,在激活结束后利用多信息量测试系统分别测试了样品的光谱响应,其最大量子效率分别为13%和20%,依据激活后光电阴极的光谱响应作为评估标准,可以得出,采用组份渐变AlxGa1-xN作为缓冲层激活出的阴极具有更高的光电发射性能,从而实现了GaN光电阴极结构的优化设计。 相似文献
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不同结构的反射式GaAs光电阴极的光谱特性比较 总被引:1,自引:1,他引:0
利用分子束外延生长了三种结构的反射式GaAs光电阴极,其中一种为传统结构的反射式GaAs光电阴极,另外两种为具有GaAlAs缓冲层的均匀掺杂和梯度掺杂反射式GaAs光电阴极.激活后的光谱响应测试结果表明,与传统结构的反射式GaAs光电阴极相比,具有GaAlAs缓冲层的均匀掺杂反射式GaAs光电阴极的长波响应更好,而具有GaAlAs缓冲层的梯度掺杂反射式GaAs光电阴极相比其它结构的反射式GaAs光电阴极能够获得更好的光电发射性能,光谱响应曲线更平坦,拟合光谱响应曲线结果表明其电子扩散长度和电子表面逸出几率都得到了增加,从而具有更高的积分灵敏度和长波响应. 相似文献
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采用聚氧化乙烯(PEO)作为聚合物太阳能电池的阴极修饰层,以P3HT:PCBM为活性层制备了聚合物本体异质结太阳能电池。考察了PEO的厚度对器件光伏性能及稳定性的影响。比较了加入PEO修饰层前后器件的稳定性,研究了采用PEO修饰层前后器件电阻的差异。结果表明:加入PEO作为阴极修饰层后器件的光电性能(JSC,VOC,FF,PCE)均有明显提高,而器件的串联电阻Rs则有了明显降低。没有阴极修饰层的器件的初始光电转换效率为1.92%,90 h后衰减为初始值的5%;而加入PEO修饰层后初始光电转换效率为3.36%,90 h后仅衰减为初始值的20%,光电转换效率提高了75%,稳定性提高了3倍。 相似文献
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《Electron Devices, IEEE Transactions on》1972,19(11):1178-1180
The sensor is a gas-filled tube of the Geiger-Mueller type, in which an electron emitted from a photocathode is accelerated by an applied electric field to cause ionization of the fill gas. Although the operating principle is not new, this tube differs from others in that the cathode consists of a semitransparent layer of metal on the inside of the cylindrical tube envelope, which is applied by sputtering after filling and sealing. Used as a cathode during sputtering, the anode consists of a pin along the axis of the tube, providing the cylindrical symmetry for uniform wide-angle viewing. The performance of the tube is compared with that of a tube of the same external dimensions, but with more conventional parallel wire electrodes. The counting rate for the sputtered tube was a factor of 10 higher than the conventional tube, due to the larger sensitive cathode area, and uniform over 360° in a plane perpendicular to the tube axis, due to cylindrical symmetry. The counting rate for the sputtered tube was 2000/min in response to a flame 7 ft away burning natural gas at the rate of 138 cm3/min. 相似文献
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Xiaohui Yang Ruixue Wang Changjun Fan Guoqing Li Zuhong Xiong Ghassan E. Jabbour 《Organic Electronics》2014,15(10):2387-2394
We report inverted light emitting devices using ethoxylated polyethylenimine (PEIE) as a single electron injection layer for indium tin oxide cathode, which possess comparable efficiency to those using ZnO/PEIE double electron injection layers. Implementation of a PEIE layer between light emitting polymer layer and aluminum has been shown to significantly enhance device efficiency as well. Improvement of device efficiency can be attributed to increased electron injection due to the reduced work function of PEIE modified cathode as well as the hole blocking effect of PEIE layer. Furthermore, PEIE serves as an efficient electron injector for a range of light emitting polymers with wide distribution of energy levels. 相似文献
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Kun-Mo Chu Jung-Sub Lee Han Seo Cho Hyo-Hoon Park Duk Young Jeon 《Electronics Packaging Manufacturing, IEEE Transactions on》2004,27(4):246-253
Alloys of lead-tin system are the most common solder alloys used today. However, there are environmental and health issues concerning the toxicity of lead present in these lead-tin solder alloys. Also, the flux residue removal is mandatory and leads to environmental threats. More importantly, the use of flux may contaminate the optically active surface by organic residue leftover, and a conventional cleaning method may not be effective for optoelectronic assemblies. Therefore, it is necessary to look for fluxless soldering processes for soldering optoelectronic systems. In the present study, we have conducted low-temperature flip-chip bonding of vertical-cavity surface-emitting laser (VCSEL) arrays on a glass substrate that provides propagation paths of laser beams and also supports a polymeric waveguide. Considering both the die shear test and the spreading test, the appropriate bonding temperature and pressure using indium solder bump were found to be about 150/spl deg/C/500 gf. The fracture occured between the indium solder bump and the VCSEL chip pad during the die shear test. It is inferred that both the low bonding temperature and the oxide layer which is formed on the surface of the indium solder prevented the bump from interacting with the chip pad. We expect the thin silver layer coating on the indium bump to protect the inner indium solder from oxidation and to decrease the melting temperature of the indium solder. Thus, we try coating a thin silver layer onto the indium surface. An eutectic reaction occurs at 97 wt.% of In with an eutectic point of 144/spl deg/C and the outer silver layer interacts with indium to form a AgIn/sub 2/ compound layer due to the high interdiffusion coefficient. As a result, the thin silver layer coated on the solder bump is very effective to enhance the adhesion strength between the indium bump and the VCSEL chip pads by decreasing the melting temperature of the indium solder bump locally. 相似文献
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Tiefeng Liu Lulu Sun Xinyun Dong Youyu Jiang Wen Wang Cong Xie Wenwu Zeng Yang Liu Fei Qin Lu Hu Yinhua Zhou 《Advanced functional materials》2021,31(51):2107250
Cathode with low work-function (WF) is a vital unit in optoelectronic devices. Yet, the stable cathode is still a big challenge. Here, PEDOT:PSS-TBA is reported among series of PEDOT:PSS-M, where PEDOT:PSS denotes poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), M refers to monovalent cation and TBA is tetrabutylammonium specifically, as a stable cathode. The PEDOT:PSS-TBA is synthesized via ion exchange with WF of 4.1–4.2 eV and its conductivity can be improved to 300 S cm−1 by the additive. Meanwhile, PEDOT:PSS-TBA is stable even under plasma, heat, or isopropanol sonication. Organic solar cells (OSCs) are fabricated with indium tin oxide (ITO)/PEDOT:PSS-TBA and highly conductive PEDOT:PSS-TBA (with additive, hc-PEDOT:PSS) electrodes respectively. The OSCs display superior stability than the reference with ITO/ZnO as the cathode. As a proof of concept, solution-processed OSCs are demonstrated with a three-layered structure (hc-PEDOT:PSS-TBA/active layer/PEDOT:PSS), which proves PEDOT:PSS-TBA as a promising cathode for printable optoelectronic with a simplified structure. 相似文献
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Ai-Li Shi Yan-Qing Li Zai-Quan Xu Fu-Zhou Sun Jian Li Xiao-Bo Shi Huai-Xin Wei Shuit-Tong Lee Satoshi Kera Nobuo Ueno Jian-Xin Tang 《Organic Electronics》2013,14(7):1844-1851
An efficient inverted polymer solar cell (PSC) is reported by integrating a small molecular electron collection layer (ECL) between indium tin oxide (ITO) cathode and the photoactive layer of blended poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM). The ECL is composed of a cesium carbonate-doped tris(8-hydroxyquinolinato) aluminum (Cs2CO3:Alq3) layer. As determined by photoelectron spectroscopy and electrical measurements, the Cs2CO3 doping induces suitable energy level alignment at the ITO/Cs2CO3:Alq3/PCBM interface and the increase in bulk conductivity of organic ECL, which are favorable to electron extraction through Cs2CO3:Alq3 to ITO cathode. In addition, optical simulation indicates that the Cs2CO3:Alq3 layer can act as an optical spacer to modulate the region of highest incident light intensity within the photoactive layer, where absorption and charge dissociation are efficient. The inverted PSC with an optimized Cs2CO3:Alq3 ECL exhibits a power conversion efficiency of 4.83%. The method reported here provides a facile approach to achieve high-performance inverted PSCs at low processing temperature. 相似文献
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Copper indium gallium selenium (CIGS) thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is covered by the buffer layer and absorption layer. Traditionally, cadmium sulfide (CdS) is inserted into the middle of the window layer (ZnO) and absorption layer (CIGS) as a buffer layer. However, the application of the GIGS/CdS thin film solar cells has been limited because of the environmental pollution resulting from the toxic cadmium atom. Although zinc sulfide (ZnS) has been proposed to be one of the candidates, the performance of such battery cells has not been investigated. Here, in this paper, we systematically study the possibility of using zinc sulfide (ZnS) as a buffer layer. By including the effects of thickness, concentration of a buffer layer, intrinsic layer and the absorbing layer, we find that photoelectric transformation efficiency of ZnO/ZnS(n)/CIGS(i)/CIGS(p) solar cell is about 17.22%, which is qualified as a commercial solar cell. Moreover, we also find that the open-circuit voltage is~0.60 V, the short-circuit current is~36.99 mA/cm2 and the filled factor is~77.44%. Therefore, our results suggest that zinc sulfide may be the potential candidate of CdS as a buffer layer. 相似文献
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Wenhui Lu Hang Song Yixin Jin Haifeng Zhao Zhiming Li Hong Jiang Guoqing Miao 《Microelectronics Journal》2008,39(5):782-785
An efficient way to improve field emission characteristic of carbon nanotubes (CNTs) through an Ag micro-particle intermediation layer is presented. In this way, the intermediation layer is deposited on an indium tin oxide glass substrate by electrochemical method and then the CNTs are covered onto surface of the intermediation layer by electrophoretic method as CNT field emitters. The field emission characteristic of the CNT field emitters with the intermediation layer is significantly improved compared to the one without the intermediation layer, including decreased turn-on electric field from 4.2 to 3.1 V/μm and increased emission current density from 0.224 to 0.912 mA/cm2 at an applied electric field of 6 V/μm. The improved field emission characteristic may be attributed to gibbous surface of the CNT field emitters. This efficient way is much simple, low cost, and suitable for production of large scale CNTs–based field emission cold cathode. 相似文献
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Zai-Quan XuJin-Peng Yang Fu-Zhou SunShuit-Tong Lee Yan-Qing Li Jian-Xin Tang 《Organic Electronics》2012,13(4):697-704
An efficient inverted polymer solar cell is enabled by incorporating an n-type doped wide-gap organic electron transporting layer (ETL) between the indium tin oxide cathode and the photoactive layer for electron extraction. The ETL is formed by a thermal-deposited cesium carbonate-doped 4,7-diphenyl-1,10-phenanthroline (Cs2CO3:BPhen) layer. The cell response parameters critically depended on the doping concentration and film thickness of the Cs2CO3:BPhen ETL. Inverted polymer solar cell with an optimized Cs2CO3:BPhen ETL exhibits a power conversion efficiency of 4.12% as compared to 1.34% for the device with a pristine BPhen ETL. The enhanced performance in the inverted device is associated with the favorable energy level alignment between Cs2CO3:BPhen and the electron-acceptor material, as well as increased conductivity in the doped organic ETL for electron extraction. The method reported here provides a facile approach to optimize the performance of inverted polymer solar cells in terms of easy control of film morphology, chemical composition, conductivity at low processing temperature, as well as compatibility with fabrication on flexible substrates. 相似文献