有机/无机复合结构光电导型器件的光激发机制

制备了PVK/ZnS有机无机复合的光电导型器件 ,器件结构分别为Glass/ITO/PVK/Al;Glass/ITO/ZnS/Al;Glass/ITO/ZnS/PVK/Al。通过研究此复合器件在外加电场作用下的稳态光电导激发谱 ,得到了基本光激发过程。把PVK/ZnS的吸收谱和器件的光电导谱进行比较 ,知道虽然两者的吸收对器件光电流都有贡献 ,但有效部分在PVK和ZnS的界面处。最大光电流对外加电场的依赖性与器件的暗电流和光电流谱为此提供了证据     

Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers

In this work, bathocuproine (BCP) and bathophenanthroline (Bphen), commonly used in small-molecule organic solar cells (OSCs), are adopted as the buffer layers to improve the performance of the polymer solar cells (PSCs) based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-nm BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen (i) increasing the optical field, and hence the absorption in the active layer, (ii) effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum (Al) interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance (Rs), and (iii) preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode.     

Synthesis of ZnO quantum dots and their agglomeration mechanisms along with emission spectra based on ageing time and temperature

The ZnO quantum dots (QDs) were synthesized with improved chemical solution method. The size of the ZnO QDs is exceedingly uniform with a diameter of approximately 4.8 nm, which are homogeneously dispersed in ethanol. The optical absorption edge shifts from 370 nm of bulk material to 359 nm of QD materials due to the quantum size effect, while the photoluminescence peak shifts from 375 nm to 387 nm with the increase of the density of ZnO QDs. The stability of ZnO QDs was studied with different dispersion degrees at 0 ℃ and at room temperature of 25 ℃. The agglomeration mechanisms and their relationship with the emission spectra were uncovered for the first time. With the ageing of ZnO QDs, the agglomeration is aggravated and the surface defects increase, which leads to the defect emission.     

ZnS∶TbF_3薄膜电致发光器件性能的研究

用射频磁控溅射和扫描电子束蒸发方法研究制备了ZnS∶TbF3薄膜的交流电致发光器件。研究了制备ZnS∶TbF3薄膜电致发光器件的几种因素对电致发光器件性能的影响 ,诸如 ,磁控溅射过程中衬底温度 ,发光层厚度 ,退火等。     

Estimation of luminescence lifetime in frequency domain

Absorption is the origin of luminescence. But it must be noticed that the lifetime of luminescence might reversely influence the rate of absorption. In this paper, it is reported that the luminescence intensity of copper and manganese changes with the driving frequency at constant voltage.The variation of luminescent intensity depends only on the lifetime of luminescence but not on the type of quenching or other factors. Generally the rate of absorption is dominantly determined by the material property and the lifetime of luminescence centres, the absorption of shorter lifetime centre will be larger than that of the longer lifetime centre at the same excited condition.     

窄谱带绿色有机电致发光器件

以Tb³⁺:水杨酸(Tb³⁺:(SA)₃)为空穴传输层兼发光层、高荧光材料Alq₃为电子传输层,得到了窄谱带的绿色有机薄膜电致发光双层结构器件.实验证实,双层器件的电致发光是电荷载流子隧穿内界面(Tb³⁺:(SA)₃/Alq₃)之后分别在两有机层内的复合发光,是两有机层本征发光的叠加.其光谱随着电子传输层厚度而改变,因而减少电子传输层厚度能得到亮度高、稳     

怀念严懋勋教授

严懋勋(William MYEN)教授(美国乔治亚大学)因病,不幸于2008年1月17日逝世。自我国改革开放以来,严教授为推动我国发光学研究的国际化,开展与国际先进研究工作的交流,付出了积极的努力,给予了大力的支持。在他的倡导和支持下,我们先后于1987年和2005年承办和组织了两次国际发光学术会议。多年来,严教授还担任了《发光学报》编辑委员会的国际顾问,对《发光学报》学术质量的提高付出了辛勤。我刊于本期特辟专栏,刊登徐叙2院士、严懋勋教授的同事、合作者和学生们撰写的专文,以永远纪念和缅怀严懋勋教授。     

ZnO薄膜受激发射特性的研究

氧化锌薄膜因其大的激子结合能和强的光发射、激光阈值低和能在高温下工作等优点而成为制备短波长激光、发光二极管等光电子器件的有希望材料。采用激光分子束外延 (L MBE)方法制备了ZnO薄膜。在室温下 ,测量了样品的吸收光谱 ,以及不同光泵浦强度下的发射光谱。从光谱图中可以看出该材料有很好的质量。研究了ZnO薄膜的受激发射特性及机理 ;测量了发射光强与泵浦光强之间的关系 ;比较了较高激发密度下的受激发射、自发发射和激光脉冲的时间特性 ,这些都证实了该发射是受激发射。     

导带电子与电离发光中心的复合(英文)

<正> In electroluminescence the extrinsic light emission follows the impact excitation of discrete centers and the impact ionization of recombination centers. From our experiments we found that these processes are quite different in their behaviour. In case of discrete centers the emission is almost independent on the nature of applied voltage (dc or ac voltage). But     

叶绿素A(Chla)溶液发光同浓度的关系

我们在发光研究中,采用激发样品表层方法抑制自吸收—再发射的作用,得到较好结果,Chla己烷溶液和Chla乙醇溶液,在低浓度均有发光主峰683nm和次峰720nm,Chla己烷溶液发光在浓度为1×10-5M时开始浓度猝灭;Chla乙醇溶液发光,在5×10-4M时仍未见明显浓度猝灭。Chla己烷溶液发光,在不同浓度下,发光峰位基本不变,在高浓度尚有弱峰760nm。Chla己烷溶液发光主峰663nm随浓度增加向长波方向移动。