有机半导体苝的DFT理论计算研究

采用密度泛函理论(DFT)方法对苝进行了B3LYP/6-31G水平上的分子结构优化、IR光谱、Raman光谱、THz光谱、UV-Vis光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现苝的THz光谱有三个特征吸收峰,它们分别位于2.94、5.46和7.77 THz,其中5.46 THz的吸收是最强的,它是由以C4-C1-C11-C16为轴的苝分子面外对称弯曲振动产生的。苝在UV-Vis光波段有三个吸收峰,峰值波长分别位于420.79、328.14及303.80 nm,其中420.79nm的紫外吸收峰最强。前线轨道计算表明苝分子的HOMO与LUMO能量差值为3.077eV,它与用UV-Vis的理论计算能隙2.946eV仅有0.131eV(4.45%)的偏差。     

有机半导体ADN的DFT理论计算研究

采用密度泛函理论(DFT)方法对9,10-二(2-萘基)蒽(ADN)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱、分子前线轨道、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现ADN在0.1～10 THz波谱范围内有5个明显的吸收峰,分别位于1.08、2.52、4.44、5.64及6.60 THz,其中5.64 THz的吸收是最强的,它是由萘环面外弯曲及蒽环面内摇摆振动产生的。ADN在紫外光波段有三个吸收峰,分别对应于386.34、352.98及352.50nm,其中386.34 nm的紫外吸收峰最强。ADN理论计算能隙值为3.516 eV,比实验值3.2 eV略高。ADN的Mulliken电荷计算表明,所有H原子的Mulliken电荷皆为正电荷,C原子Mulliken电荷与其具体的化学环境相关。     

OLED绿光掺杂剂DMQA的DFT理论计算研究

采用密度泛函理论(DFT)方法对N,N'-二甲基喹吖啶酮(DMQA)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外.可见光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算.研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射...     

GHB光学性质的DFT理论计算研究

采用密度泛函理论( DFT)方法对γ-羟基丁酸(GHB)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱及分子前线轨道理论等计算.研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现GHB在0.1 ～...     

有机半导体Butyl-PBD的DFT理论计算研究

采用密度泛函理论(DFT)方法对2-(4-叔丁苯基)-5-(4-联苯基)-1,3,4-恶二唑(Butyl-PBD)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算.研究结果表明:理论计算结果与实验数据吻合得较好,对IR...     

微量Co2+掺杂ZnO粉体的结构和光学性能研究

采用球磨法制备了Zn1-xCoxO(x=0,0.004,0.008)纳米粉体,分别利用XRD,PL光谱和紫外-可见吸收光谱对样品进行了表征。XRD图谱显示样品呈六方纤锌矿结构,随着Co2+离子掺杂量的增加,晶格常数和平均晶粒尺寸略有减小。在PL光谱上观察到三个发光带:370nm处的本征发光峰、468nm附近的强蓝光发光峰,以及533nm附近的绿光发光峰。和球磨样品相比,1 200℃退火的样品的发光强度明显增强,这归因于退火使样品晶粒长大。在紫外-可见吸收谱上可以观察到两个吸收带:由ZnO的带隙吸收引起的360～388nm的强紫外吸收带和由Co2+离子的d-d跃迁引起的565nm附近的可见光吸收带。因此通过调节Co2+掺杂量和选择适当的退火温度可制备高质量的发光材料。     

蓝光材料9,10-二(β-萘基)蒽的合成与光谱分析

采用还原β-萘基锂与蒽醌的加成物制备了有机电致蓝光材料9,10-二(β-萘基)蒽(ADN)。通过红外、核磁共振对其结构进行了表征。利用紫外可见吸收光谱、循环伏安法和荧光光谱等研究了其HOMO、LUMO能级及发光性能。紫外可见吸收光谱有2个吸收带,其中E带有2个吸收峰,波长分别为232nm、260nm;B带有3个吸收峰,其波长分别为359nm、377nm、398nm,ADN的吸收带边为420nm,计算其能级差为2.95eV。采用398nm的激发光激发,荧光发射峰值波长为426nm,半峰宽为56nm,有很好的蓝光色纯度。通过循环伏安法测得其氧化峰电位为1.28 V,推算出ADN的HOMO能级为5.60 eV,LUMO能级为2.65 eV。     

氧气中退火Ge-SiO2共溅射薄膜的强紫光发射

Ge-SiO2共溅射薄膜分别在O2、N2和空气中退火后,在Xe灯250nm线激发下,均观测到位于400和300nm的紫、紫外光发射(PL).傅里叶变换红外吸收谱(FT-IR)表明,这两个PL峰与锗氧化物紧密相关.进一步的光致发光激发谱(PLE)则证实它们来源于GeO色心的光学跃迁.对比不同退火气氛下的PL强度,发现最强的光发射出现在800℃氧气里退火的样品中.这表明,退火气氛中氧的存在,能够增强Ge-SiO2共溅射薄膜的紫、紫外光发射,是一种增强光发射强度的新途径.     

真空还原制备的VO_2热致相变薄膜光学性质研究

本文对不同衬底制备的VO2 薄膜进行了表面形貌测试 ,对其红外透射光谱和Raman光谱进行了研究 ,并进行 370nm -90 0nm波段的光透射测试以及 90 0nm波长的热滞回线特性测试 ,表明所制备VO2 薄膜具有优良的热致相变光学特性 ,薄膜为纳米结构 ,并且结晶状态不同的薄膜其Raman谱位置有明显改变 ,室温时的红外光谱表现出较好的红外振动特性。讨论了薄膜结晶状态对Raman位移的影响以及VO2 薄膜的红外光谱     

Li_2的405～460nm范围内的吸收及发射谱

本文报道了锂双原子分子在405～460nm范围内的吸收谱,吸收峰在422.5nm和450nm附近,两个吸收峰应来自x~3∑_u~+→2~3II_g的吸收跃迁.激光泵浦得到了456nm附近的感生荧光谱,并对这一谱带的发射机理进行了讨论.     

Properties of Light Emission Spectrum of Double-barrier Tunnel Junction

Fabricated are the double-barrier light emission tunnel junctions successfully. Introduced are the fabrication process and light emission characteristics. The spectra of the junctions are measured and analyzed especially. Their spectrum wavelength including main wave peak（locates at 450 nm～500 nm） of the double- barrier junction shows a ＂blue shift＂ in comparison with that of the single-barrier Metal/Insulator/ Semiconductor（MIS） or Metal/Insulator/Metal（MIM） junction（wave peak locates at 620 nm-740 nm）. This phenomenon should be due to the occurrence of the electron resonant tunneling in the double-barrier junction.     

Synthesis and Room‐Temperature Ultraviolet Photoluminescence Properties of Zirconia Nanowires

This paper reports the synthesis of tetragonal zirconia nanowires using template method. An as‐prepared sample was characterized by scanning and transmission electron microscopy. It was found that the as‐prepared materials were tetragonal zirconia nanowires with average diameters of ca. 80 nm and length of over 10 μm. The Raman spectrum showed peaks at 120, 461, and 629 cm^–1, which are attributed to the E_g, E_g, and B_1g phonon modes of the tetragonal zirconia structure, respectively. The UV‐vis absorption spectrum showed an absorption peak at 232.5 nm (5.33 eV in photon energy). Photoluminescence (PL) spectra of zirconia nanowires showed a strong emission peak at ca. 388 nm at room temperature, which is attributed to the ionized oxygen vacancy in the zirconia nanowires system.     

Synthesis and photoluminescence properties of the 4H-SiC/SiO2 nanowires

4H-SiC/SiO2 nanowires are synthesized and the temperature-dependent photoluminescence （PL） properties of the nanowires are studied. Their structure and chemical composition are studied by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and Raman spectra. At room temperature, an ul- traviolet PL peak and a green PL band are observed. From the PL spectrum measured in the temperature range from 80 K to 300 K, the free excition emission, donor bound excition emission and their multiple-phonon replicas have been observed in ultraviolet region, and their origins have been identified. Moreover, it has been found that the temperature dependence of the free exciton peak position can be described by standard expression, and the thermal activation en- ergy values extracted from the temperature dependence of the free exciton and bound exciton peak integral intensity are about 40 meV and 181 meV, respectively.     

Epitaxy and Characteristics of Resonant Cavity LEDs at 650 nm

Resonant-cavity light-emitting diodes (RCLED) at 650 nm wavelength were grown by metal organic chemical vapor deposition. In order to improve the interface quality and reduce the device voltage, an AlGaInP material system has been chosen to grow the top DBRs. The emission properties of the RCLED were characterized by measuring PL and EL spectra. The average emission power of the device is 0.5 mW at 20 mA and 2.2 V, and its spectrum full width at half maximum is about 10 nm.     

650纳米谐振腔发光二极管外延生长及性能研究

采用金属有机化学气相淀积（MOCVD）方法生长了波长为650nm的谐振腔发光二极管（RCLED）。为提高界面生长质量,降低压降,采用AlGaInP材料系制作上DBRs。利用光致发光谱（PL）与电致发光谱（EL）研究了其发光特性。得到的器件在20mA注入电流下光功率平均为0.5mW,压降2.2V,光谱半峰宽（FWHM）约10nm。     

New semi-conducting rotaxane based on β-cyclodextrin and anthracene moieties

A new rotaxane (BPAAn/β-CD), consisting of an anthracene-based semi-conducting material (BPAAn) encapsulated into β-cyclodextrin (β-CD), has been synthesized via the Williamson reaction in solvent-free conditions. The supramolecular structure of the compound was confirmed by NMR and FT-IR spectroscopies. The optical and morphological properties of this organic material were investigated by UV–visible absorption, photoluminescence spectroscopy and atomic force microscopy. BPAAn/β-CD film has an optical gap of 2.9 eV and exhibits green photoluminescence. An optical gap of 2.9 eV was estimated from the absorption edge of the rotaxane thin film. The BPAAn/β-CD exhibits a blue photoluminescence in dilute solution; whereas, a green emission was observed in the solid state, due to the π–π interaction in the anthracene moieties. The rotaxane shows a significantly enhanced PL quantum yield and improved film quality in comparison with the free BPAAn. The HOMO and LUMO levels were estimated using cyclic voltammetry analysis, and show enhanced electron affinity of the BPAAn in its complexed form. A single-layer device with the configuration [ITO/rotaxane/Aluminum] has been elaborated and showed low turn-on voltage of 5 V.