掺杂PVK薄膜的荧光谱及电荷转移

根据PVK掺杂后荧光谱的变化，说明掺杂PVK薄膜的电致发光存在着从基质分子向掺杂分子的能量传递，用一个由单链模型扩展到包括杂质的哈密顿量进行数值求解，结果表明：在PVK和杂质分子之间有效的能量传递是源于它僮之间的电荷转移，且随着杂质浓度的变化，其荧光谱峰位的移动与掺杂前后系统总能量的改变及荧光谱强度与掺杂后转移的电荷数之间分别存在对应关系。该模型较好地解释了有关的实验结果。     

PVK:DBVP掺杂体系的能量转移及发光性质的研究

研究了不同比例的PVK与齐聚PPV衍生物DBVP掺杂体系的能量转移和发光特性.通过对PVK，DBVP及PVK: DBVP掺杂体系的UV-vis，PL和PLE光谱的研究，分析了PVK与DBVP之间的能量转移过程.利用PVK在体系中类似于溶剂的分散作用，制备了结构为ITO/PEDOT/PVK: DBVP/LiF/Al的电致发光器件，研究了掺杂体系的电致发光性能.结果表明，在掺杂体系的光致发光和电致发光中，PVK的发射被有效地抑制，PVK与DBVP之间发生了非常有效的能量转移，通过调节PVK与DBVP的比例，可以获得蓝色和绿色发光，同时可以改善器件的发光性能，当PVK与DBVP的重量比为1∶2时，器件的绿色发光效率达到1.06cd/A，此时发光亮度为52cd/m².     

PVK∶DBVP掺杂体系的能量转移及发光性质的研究

研究了不同比例的PVK与齐聚PPV衍生物DBVP掺杂体系的能量转移和发光特性.通过对PVK,DBVP及PVK:DBVP掺杂体系的UV-vis,PL和PLE光谱的研究,分析了PVK与DBVP之间的能量转移过程.利用PVK在体系中类似于溶剂的分散作用,制备了结构为ITO/PEDOT/PVK:DBVP/LiF/Al的电致发光器件,研究了掺杂体系的电致发光性能.结果表明,在掺杂体系的光致发光和电致发光中,PVK的发射被有效地抑制,PVK与DBVP之间发生了非常有效的能量转移,通过调节PVK与DBVP的比例,可以获得蓝色和绿色发光,同时可以改善器件的发光性能,当PVK与DBVP的重量比为1∶2时,器件的绿色发光效率达到1·06cd/A,此时发光亮度为52cd/m2.     

掺杂PPQ薄膜的电致发光及电场调制

从掺杂PPQ薄膜单层器件的电致发光光谱在掺杂前后的变化。说明掺杂PPQ薄膜中存在着基质分子和掺杂分子间的能量传递，其电致发光光谱随加电场变化说明电场对PPQ薄膜的电致发光具有调制作用。用一个由单链模型扩展到包括杂质和外场的Hamiltonian进行数值求解。结果表明：在PPQ和TPL分子之间有效的能量传递是源于它们之间的是荷转移，且随着外加电压的变化，其电致发光谱峰位的移动与掺杂前后系统总量的改变及发光强度与掺杂后转移的电荷数之间分别存在对应关系，这一模型很好地解释了电场对PPQ薄膜电致发光的调制作用。     

掺杂8－羟基喹啉铝薄膜的电致发光特性研究

在具有电致发光（ＥＬ）的有机整合染料８－羟基喹啉铝（Ａｌｑ３）中接以染料罗丹明６Ｇ（Ｒ６Ｇ）,用真空热蒸发的方法制备器件,获得了峰值波长５７５ｎｍ的黄色直流薄膜电致发光,从而通过掺杂改变了发光颜色．并在Ａｌｑ３发光层不同区域插入一掺杂薄层（Ａｌｑ３：Ｒ６Ｇ）,利用其发光波长与未掺杂部分（Ａｌｑ３）的不同,以此作为“探测层”,通过对器件光谱及电学特性的测量与分析,探讨了有关发光区域,发光机理,界面对发光影响等基本问题．     

掺杂8-羟基喹啉铝薄膜的电致发光特性研究

在具有电致发光(EL)的有机整合染料8-羟基喹啉铝(Alq3)中接以染料罗丹明6G(R6G),用真空热蒸发的方法制备器件,获得了峰值波长575nm的黄色直流薄膜电致发光,从而通过掺杂改变了发光颜色.并在Alq3发光层不同区域插入一掺杂薄层(Alq3:R6G),利用其发光波长与未掺杂部分(Alq3)的不同,以此作为“探测层”,通过对器件光谱及电学特性的测量与分析,探讨了有关发光区域,发光机理,界面对发光影响等基本问题.     

芴-咔唑新型共聚物/PVK掺杂体系的电致发光特性研究

研究了新型的芴-咔唑共聚物(PFC)与聚乙烯咔唑(PVK)掺杂体系的光致发光和电致发光特性.制备了结构分别为indium-tin-oxide(ITO)/PVK:PFC/bathocuproine(BCP)/tris-(8-hydroxylquinoline)-aluminum (Alq₃) /Mg:Ag，ITO/PFC/BCP/Alq₃/Mg∶Ag和ITO/PVK/BCP/Alq₃/Mg∶Ag的三种有机电致发光器件.对器件的光电特性进行了测试.结果表明，掺杂体系中的PVK有效地抑制了固态膜中PFC激基缔合物的形成.掺杂器件在不同的外加电场作用下发生发光层位置的移动，通过调节外加电场，可以获得从绿光到蓝光的可见光发射.当外加电压大于7V时，掺杂器件的蓝色发光亮度达到1650cd/m²，推测其中可能存在从PVK到PFC的能量传递过程.     

掺杂有机电致发光中电压调制变色两种机制的探讨

研究两种掺杂电致发光器件聚乙烯基咔唑（PVK）：Rubrene和Alq3:MN-PPV。通过其光致发光及电致发光特性的研究，发现两种器件的光致发光与电致发光有较大差别。分析认为这是能量传递及电致发光中陷阱对载流子吸引的共同作用使得PVK激子在光致发光和电致发光中的复合速率不同造成的；同时发现对于不同浓度的PVK：Rubrene及Alq3:MN-PPV电致发光随电压增加都发生变色现象，但是它们分别是由两种不同的机制造成的：前者作为染料分子Rubrene，不能形成类似Alq3那样的分相体系，Rubrene发光主要来自PVK的能量传递及陷阱电子对PVK空穴的吸引；后者是由于分相造成载流子在两相中的迁移不平衡。     

基于PVK∶NPB掺杂体系的有机电致发光器件的性能

利用溶液旋涂的方法,通过改变复合功能层中poly(N-vinylcarbazole)(PVK)和N,N′-bis-(1-naph-thyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(NPB)的质量比,制备结构为indium-tin-oxide(ITO)/PVK:NPB/2,9-dimenthyl-4,7-diphenyl-1,10-phenanthroline(BCP)/Mg:Ag的有机电致发光器件,并对器件的电致发光特性进行了表征。研究结果表明,当复合功能层中PVK和NPB的质量比为1:1时器件性能最好,在该器件的电致光谱中,除了NPB的本征谱峰外,在长波方向还出现了一个位于640nm处的谱峰,这是PVK和NPB产生的电致激基复合物发光,并且随着驱动电压的增加,电致激基复合物的发光强度也相对增强。     

La掺杂Bi-2201单晶中宏观相分离迹象的发现及研究

在对系列Ｌａ 掺杂的Ｂｉ２Ｓｒ２ － ｘＬａｘＣｕＯ６ ＋ δ单晶的研究中,我们发现在极度Ｌａ 掺杂（ 空穴极度欠掺杂） 的样品中有高达３６Ｋ 的超导相出现．Ｘ 射线衍射图（ＸＲＤ） 和电镜照片都表明这种极度空穴欠掺的样品有很好的单相性,从而排除了样品化学不纯的可能．另外,对这种样品进行脱氧处理后,此超导电性相应消失,说明了这种高Ｔｃ 的超导电性是由活动性空穴掺杂引起的．虽然对相应样品在正常态的磁测量没有测出反铁磁峰（Ｎｅｅｌ 峰） ,但对系列样品的拉曼散射研究发现样品随着Ｌａ 含量的增多,其反铁磁交换作用明显加强．所以,我们认为这种高Ｔｃ 超导电性的出现是在Ｂｉ２２０１ 体系中存在宏观相分离的明显迹象     

Investigation of Interpolymer Complexation Between Poly(Vinylcaprolactam) and Poly(Maleic Acid-Alt-Styrene)

The interactions between two synthetic polymers used in biomedical applications, maleic acid-styrene copolymer (MAc-St) and poly(vinylcaprolactam) (PVCL), were investigated in dilute aqueous solution considering the influence of the pH, the added salt and the ratio between the components in the mixture. Hydrogen-bonding interactions between the COOH groups of MAc-St and the C═O groups of PVCL, together with hydrophobic interactions are involved in the formation of the interpolymer complex. The complex is insoluble below pH = 2.85 in aqueous solution, but the addition of NaCl enlarged the pH domain where the precipitation of the complex occurred. When the ratio between the polymers was varied, two maxima of the optical density were obtained: at a 1:1 ratio between the COOH and caprolactam groups, and also at a lower ratio (1:3). Other investigations, like the measurements of the turbidity in situ during mixing, and fluorescence, viscometric and potentiometric measurements were performed in order to understand these interactions. The phase separation of the thermosensitive poly(vinylcaprolactam) in the presence of MAc-St was also studied. The cloud point and the phase transition profile were found to be influenced by the amount of polyacid, as well as by the pH.     

PMMA掺杂对P3HT/P(VDF-TrFE)复合薄膜阻变性能影响研究

Organic semiconducting/ferroelectric blend films attracted much attention due to their elec-trical bistability and rectification properties and thereof the potential in resistive memory devices. Blend films were usually deposited from solution, during which phase separation oc-curred, resulting in discrete semiconducting phase whose electrical property was modulated by surrounding ferroelectric phase. However, phase separation resulted in rough surface and thus large leakage current. To further improve electrical properties of such blend films, poly(methyl metacrylate) (PMMA) was introduced as additive into P3HT/P(VDF-TrFE) semiconducting/ferroelectric blend films in this work. It indicated that small amount of PMMA addition could effectively enhance the electrical stability to both large electrical stress and electrical fatigue and further improve retention performance. Overmuch PMMA addition tended to result in the loss of resistive switching property. A model on the con-figuration of three components was also put forward to well understand our experimental observations.     

塑料光纤相位调制灵敏度的研究

研究了压电涂层PMMA纤芯塑料光纤中的相位调制.射频信号通过对光纤外层的压电涂层作用,使纤芯中产生应变,从而对光纤中的光信号进行相位调制.数值计算结果表明,与传统的石英光纤相比,PMMA塑料光纤的相位调制的灵敏度要高数十倍以上.     

Critical behavior in Co-doped manganites La0.67Pb0.33Mn1−xCoxO3 (0≤x≤0.08)

The critical properties of perovskite manganite La_0.67Pb_0.33Mn_1−xCo_xO₃ (0≤x≤0.08) around the paramagnetic-ferromagnetic phase transition are investigated through various techniques such as the modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis. Though the nature of this transition was found to be in second order, the estimated critical exponents β (0.233≤β≤0.368), γ (1.03≤γ≤1.40) and δ (4.32≤δ≤5.54) are in between the theoretically predicted values for three-dimensional Heisenberg and tricritical mean-field model. This model suggests the coexistence of the short-range and long-range ferromagnetic orders around the critical temperature. The values of the critical exponents obtained from different methods and the well-obeyed scaling behavior confirm that the calculated exponents are unambiguous and purely intrinsic to the system.     

聚芳香杂环甲烯的三阶非线性光学效应与时间分辨光克尔效应

合成了一系列聚芳香杂环甲烯,包括聚吡咯甲烯和聚噻吩甲烯.采用四波混频法研究材料的共振三阶非线性光学效应(λ＝532nm),其共振二阶超分子极化率γ三阶非线性光学系数分别达到10^-30esu和10^-8esu.选择具有良好溶解性、成膜性的聚吡咯对二甲氨基苯甲烯(PPDMAB),采用飞秒时间分辨光克尔效应方法研究材料的非共振三阶非线性光学效应(λ=790nm).实验表明,翠绿亚胺碱溶液的光克尔信号仅表现一超快响应的成分,归功于π电子云扭转产生的非共振激发.PPDMAB的非共振二阶超分子极化率γ三阶非线性光学系数分别达到γ=5.78×10^-32esu和χ⁽³⁾=1.26×10^-10esu.     

P3HT/PMMA双层聚合物电双稳器件的研究

通过逐层旋涂的方法,制备了P3HT(poly(3-hexylthiophene))与PMMA(poly(methylmethacrylate))双层器件,并与二者的共混溶液制备的器件进行了性能对比。利用扫描电镜(SEM)表征了双层器件的横截面形貌;利用电流-电压(I-V)以及电流-读取次数(I-t)测试,测量了两种器件的开关比以及持续时间特性。其中,双层器件具有更好的开关比,可达1×10~3,同时反复读写测试表明器件性能非常稳定。为了解释电双稳现象产生的机理,对双层结构器件的电流-电压曲线进行了线性拟合,利用器件的能级图进行分析,得出了电荷在器件中的传输过程。研究结果表明,可以通过电荷俘获释放理论解释P3HT/PMMA双层器件电双稳特性产生的机理。     

卵黄鞘磷脂与DOPC相互作用的单层膜

通过分析单层膜在固定表面压力下的过量分子面积和固定分子面积时的过量表面压力研究了卵黄鞘磷脂和1,2-二油酸基磷脂酰胆碱在单层膜中的混合性行为,通过分析过量吉布斯能量、过量亥姆霍兹能量和弹性系数评估了混合脂单层膜稳定性和压缩性. 热力学分析表明,相对于两组分理想混合时过量分子面积和过量表面压力呈现出正偏差,表明分子间的相互作用力为排斥力. 能量极值点出现在卵黄鞘磷脂含量为0.6处,表明该比例下单层膜结构状态不稳定. 排斥力诱导了单层膜中产生相分离.     

聚（2，5－二丁氧基）苯撑的三阶非线性光学性质

报道了一种新的同可溶性好的，具有连苯结构的共轭有机聚合物：聚（２，５－二丁氧基）苯撑（简称ＰＰＰ），采用四波混频方法测量了它在５３２ｎｍ和１０６４ｎｍ处的三阶非线性光学系数，由此推算了非线性折射率，并讨论了材料的优质因子，指出了材料最适用的光波段。     

Effect of Polydispersity on the Phase Behavior of Polystyrene (PS)/Poly (Vinyl Methyl Ether) (PVME)

The thermodynamics and kinetics of phase separation in partially miscible blends of poly (vinyl methyl ether) (PVME) and two kinds of polystyrene (PS) with the same weight average molecular weight but different polydispersity were studied. The miscibility of PS/PVME with the monodisperse PS was better than that of PS/PVME with the polydisperse PS. Different morphology was observed for the two kinds of PS/PVME (10/90) blends during the nonisothermal phase separation process. The blend with monodisperse PS presented a co-continuous structure while the blend with polydisperse PS presented a viscoelastic phase separated network structure at a quench depth of 29°C. With increase of the heating rate, the increase of cloud point of PS/PVME (30/70) with polydisperse PS was smaller than that of PS/PVME (30/70) with monodisperse PS. During the isothermal phase separation of the critical composition (20/80) of PS/PVME with a quench depth of 30°C, it was found that the phase morphology of the two kinds of blends was nearly the same at the early stage of phase separation. However, as the dispersed phase, an approximately spherical droplet structure was observed in the blend with monodisperse PS at the late stage of phase separation, which did not appear in the blend with polydisperse PS.