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51.
Analysis of the out-of-phase modulated photocurrent (MPC) signal, the so-called Y signal, is proposed for determining the trapping–detrapping events, recombination processes and gap-state parameters in amorphous silicon. This is demonstrated by analysing experimental Y spectra obtained on this material from different laboratories including our own. Model simulations are also employed in which the amphoteric nature of the dangling bonds and their distribution according to the defect-pool model are taken into account. From the reconstruction of the Y signal, phase shift and MPC amplitude spectra, several contributions resolved from the frequency dependence of the experimental Y spectra are identified. Two electron trapping–detrapping processes are resolved. These are attributed to hydrogen-related positive defects and to transitions involving the D+/0 level of the normal dangling bonds from the defect-pool distribution. At lower frequencies a residual contribution is resolved that is attributed to a term related to recombination through the D+/0 and D0/? levels. Between 300 and 150?K the above recombination contribution is essentially from the D0/? and dominates the Y signal at lower frequencies. In this region a characteristic phase lead appears, which is attributed to the existence of safe hole traps in the valence band tail. Around 150?K, trapping–detrapping events in the conduction band tail dominate. 相似文献
52.
Stefano Caramori Dr. Jérôme Husson Dr. Marc Beley Prof. Carlo A. Bignozzi Prof. Roberto Argazzi Dr. Philippe C. Gros Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2611-2618
Mixtures of polypyridine FeII and CoII complexes are used as electron mediators in Ru–thienyltpy‐sensitised solar cells (tpy=terpyridine). The use of the metalorganic redox couples allows for improved charge‐collection efficiency with respect to the classical iodide/iodine couple which, when associated to Ru–tpy2 dyes, usually produces poor performance. The improved charge collection is explained by a combination of effective dye regeneration and decreased recombination with the oxidised electrolyte on the basis of data obtained by transient spectroscopy and photoelectrochemical measurements. The efficiency of the regeneration cascade is also critically dependent upon the ability of the CoII complex to intercept FeIII centres, as clearly indicated by chronocoulometry experiments. 相似文献
53.
GaN激子跃迁的时间分辨光谱学研究 总被引:1,自引:1,他引:0
用时间分辨光谱学方法研究低压有机金属化学汽相沉积生长的GaN中自由,束缚激子(BX)的跃迁,讨论了这些跃迁的光致发光谱,复合寿命及其与温度的关系,给出了中性施主束缚激子和自由激子(FX)的辐射复合寿命分别为0.12ns和0.4ns。 相似文献
54.
透明带3作为精子的初级受体是透明带的一种主要糖蛋白,而抗ZP3抗体能够阻止精卵结合.因此,ZP3被认为是避孕疫苗的候选免疫原.草原兔尾鼠是新疆的重要害鼠,将它的ZP3基因序列与GenBank上已发表的几种鼠的ZP3基因序列进行同源性比较,将有助于哺乳动物受精机理的阐明与免疫不育疫苗的设计,同时也有助于了解这些鼠在系统进化中的相对地位. 相似文献
55.
简要介绍了利用高温高压合成发现的超导系列CuBa2Can-1CunO2n+2+δ,即Cu-12n(三元数法)或Cu-12(n-1)n(四元数法),简称Cu-系。比较了Cu-系和其它主要高温超导体的结构和主要性质,指出了Cu-系和YBa2Cu3O6的同构关系,以及Cu-系具有的良好的高温高场特性。Cu-系超导体因仅含碱土和铜的氧化物,化学组成简单、经济、安全,具有潜在的应用开发前景。 相似文献
56.
A. Thränhardt C. Ell G. Khitrova H.M. Gibbs 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(4):571-576
We calculate energy levels, dipole moments and radiative broadening of interface fluctuation quantum dots. For optically allowed
states, the dipole moment grows proportionally to the lateral quantum dot radius while the radiative broadening saturates
towards the quantum well radiative broadening for large lateral quantum dot radii. This is accompanied by a change in the
angular emission pattern, concentrating emission in forward and backward direction. Optically forbidden states do not couple
to light propagating in the growth direction yet they may have a considerable radiative broadening due to spontaneous emission
in other directions.
Received 20 March 2002 Published online 25 June 2002 相似文献
57.
建立了双层有机发光二极管中载流子在有机层界面复合的无序跳跃理论模型.由于有机分子材料的空间及能带结构的无序性,采用刚体模型处理有机层界面问题是不恰当的,而采用无序跳跃模型比较合理.复合效率及复合电流由载流子跳跃距离、有机层界面的有效势垒高度及该界面处的电场强度分布所决定:在双层器件ITO/α-NPD/Alq3/Al中,当所加电压小于19.5V时,复合效率随着载流子跳跃距离的增加而增加,而大于19.5V时,复合效率随着其距离的增加而减少;复合效率随着有机层界面有效势垒高度的增加而增加;
关键词:
有机层界面
双层有机发光二极管
复合效率
有效势垒高度
无序跳跃模型 相似文献
58.
O. P. Ermolaev 《Journal of Applied Spectroscopy》1997,64(4):493-496
This study was carried out to investigate low-temperature (T=4.2 K) photoluminescence caused by interdopant recombination
transitions in n-germanium irradiated by fast (epicadmium) reactor neutrons and subjected to “complete” annealing (+450°C,
24 h). It is shown that lines of interdopant radiative recombination observed in initial and in irradiated and annealed specimens
are caused by both initial impurities and (mainly) dopants (As and Ga) implanted by transmutation as well as by defect sets
stable at long-time high-temperature annealing that do not contain fine dopants.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 4, pp. 479–482, July–August, 1997. 相似文献
59.
建立了在单层有机发光二极管中电场强度不太大(E≤104Vcm)的情况下,载流子注入、传输和复合的理论模型.通过求解非线性Painleve方程得出了电场强度随坐标变化的解析函数关系式以及电流密度随电压变化关系,给出了电流密度以及器件的复合效率在不同的载流子迁移率情况下随电压变化关系图像.结果表明,复合效率受载流子迁移率影响较大,在器件中多数载流子应具有较低的迁移率,而少数载流子应具有较高的迁移率,这样有利于载流子的注入和传输,从而可提高发光效率.并且得出当空穴迁移率大于电子迁移率时,复合区域偏向阴极,反之亦
关键词:
单层有机发光二极管
复合效率
迁移率 相似文献
60.
Ultrasonic cavitation in organic solvents remains poorly understood in contrast with aqueous systems, largely because of complexities related to solvent decomposition. In this study, we sonicated different types of organic solvents (i.e. linear alkanes, aliphatic alcohols, aromatic alcohols, and acetate esters) under argon saturation. The average temperature of the cavitation bubbles was estimated using the methyl radical recombination method. We also discuss the effects of the physical properties of the solvents, such as vapor pressure and viscosity, on the cavitation temperature. The average cavitation bubble temperature and sonoluminescence intensity were higher in organic solvents with lower vapor pressure; for aromatic alcohols, these values were particularly high. It was found that the specific high sonoluminescence intensities and average cavitation temperatures exhibited in aromatic alcohols are caused by the highly resonance-stable generated radicals. The results obtained in this study are very useful for acceleration of sonochemical reaction in organic solvents, which are indispensable for organic synthesis and material synthesis. 相似文献