Barrier characteristics of biopolymer-based organic/inorganic Au/CTS/n-InP hybrid junctions

Thin film of biopolymeric compound chitosan (CTS) has been surfaced on moderately doped n-InP substrate as an interfacial layer by means of spin coating for the electronic modification of Au/n-InP structure. Electrical characterization of Au/CTS/n-InP hybrid junction has been performed by I–V and C–V measurements at room temperature. An effective barrier height (BH) value of 0.678 eV and an ideality factor of n = 1.665 have been obtained for the hybrid junction. The CTS interfacial layer has been found to reduce the reverse bias leakage current of the junction by about three orders of magnitude and enhance the BH by about 0.213 eV. Furthermore, the BH value of the hybrid junction has been obtained as 0.693 eV by C–V measurement. Good performance of the device could be ascribed to the passivation effect of the CTS interfacial layer between Au and n-InP. The BH values of 0.678 and 0.693 eV for the hybrid junction have been significantly higher than that of the conventional Au/n-InP junction (~0.465 eV). The results indicated that biopolymeric thin interfacial CTS layer might lead to the modification of the potential barrier for metal/n-InP junctions. Moreover, band gap of the CTS layer has been determined as 4.60 eV via UV–vis spectroscopy.     

Differential capacitance of hybrid organic/inorganic CdSe/ZnS quantum dots light-emitting device

We have studied the differential capacitance of self-assembly hybrid organic/inorganic quantum dot (QD) light-emitting devices (QD-OLEDs) at room temperature in the frequency range of 1×10³ to 1×10⁶ Hz. Self-assembly CdSe/ZnS QDs monolayer was used to fabricate trilayer hybrid QD-OLEDs on indium tin oxide coated glass substrates. We observed negative differential capacitance (NDC) in both OLED and QD-OLEDs for the first time in the intermediate frequency range of 5×10³ to 5×10⁵ Hz. The onset and frequency range of NDC are strongly depended on the applied bias voltage. This behavior is described by a mathematical model. The simulated results showed that the NDC was due to the time-dependent transient current from the QDs and organic/metal interfacial states in the device. The probable mechanisms of NDC in organic devices are discussed.     

溶胶-凝胶法制备有机硅掺杂有机/无机复合疏水性减反射膜的研究

以正硅酸乙酯(TEOS)和硅油为前驱体,在碱性催化体系中制备出有机硅改性二氧化硅溶胶,采用提拉法获得了具备疏水性能的二氧化硅减反膜。通过透射电镜、扫描探针显微镜、红外光谱、分光光度计、表面轮廓仪等多种方法研究了改性后的膜层性能。在高湿度环境中存放两周后,在波长确定的情况下,常规二氧化硅减反膜透过率由99.2%降到了96.5%,疏水改性膜层透过率仍然高于99%。与常规减反膜相比,疏水改性减反膜在高湿度条件下防止潮气侵蚀的性能得到了大幅度的提高。     

Converting Wannier into Frenkel excitons in an inorganic/organic hybrid semiconductor nanostructure

Electronic coupling between Wannier and Frenkel excitons in an inorganic/organic semiconductor hybrid structure is experimentally observed. Time-resolved photoluminescence and excitation spectroscopy directly demonstrate that electronic excitation energy can be transferred with an efficiency of up to 50% from an inorganic ZnO quantum well to an organic [2,2-p-phenylenebis-(5-phenyloxazol), alpha-sexithiophene] overlayer. The coupling is mediated via dipole-dipole-interaction analog to the F?rster transfer in donor-acceptor systems.     

紫外光固化聚丙烯酰/SiO2有机/无机杂化气凝胶制备

采用自制的甲基丙烯酰多羟基倍半硅氧烷制备了UV固化的有机/无机杂化湿凝胶。湿凝胶经CO2超临界干燥后即得到相应的杂化气凝胶,气凝胶经场发射扫描电子显微镜,高分辨透射电镜分析表明：构成气凝胶3维珍珠链结构的骨架的颗粒尺寸为20～30 nm,骨架上具有5～10 nm的孔洞结构,骨架颗粒有机、无机组分间没有明显的相界面。气凝胶的比表面积、吸附特性和微观孔结构采用经典的N2吸附法获得,结果表明气凝胶比表面积为520.9 m2/g,孔洞结构主要由50 nm以下的介孔所构成。     

紫外光固化聚丙烯酰/SiO2有机/无机杂化气凝胶制备

 采用自制的甲基丙烯酰多羟基倍半硅氧烷制备了UV固化的有机/无机杂化湿凝胶。湿凝胶经CO₂超临界干燥后即得到相应的杂化气凝胶,气凝胶经场发射扫描电子显微镜,高分辨透射电镜分析表明：构成气凝胶3维珍珠链结构的骨架的颗粒尺寸为20～30 nm,骨架上具有5～10 nm的孔洞结构,骨架颗粒有机、无机组分间没有明显的相界面。气凝胶的比表面积、吸附特性和微观孔结构采用经典的N₂吸附法获得,结果表明气凝胶比表面积为520.9 m²/g,孔洞结构主要由50 nm以下的介孔所构成。     

Synthesis and characterization of organic/inorganic heterostructure films for hybrid light emitting diode

Thin-film light emitting devices based on organic materials have been gathering attentions for applying a flat-panel display and a solid-state lighting. Alternatively, inorganic technologies such as Si-based thin-film technology have been growing almost independently. It is then expected that combining the Si-based thin-film technology with the organic light emitting diode (OLED) technology will develop innovative devices. Here, we report syntheses of the hybrid light emitting diode (LED) with a heterostructure consisting of p-type SiC_x and tris-(8-hydroxyquinoline) aluminum films and characterization for the hybrid LEDs. We present the energy diagram of the heterostructure, and describe that the use of high dark conductivities of the p-type SiC_x as well as inserting wide-gap intrinsic a-SiC_x at the p-type SiC_x/Alq interface are effective for improving device performance.     

Laterally inhomogeneous barrier analysis of the methyl violet/p-Si organic/inorganic hybrid Schottky structures

In this work, we have investigated the electrical characteristics, such as current-voltage (I-V) and capacitance-voltage (C-V) measurements, of identically prepared crystal violet/p-Si Organic/Inorganic (OI) Schottky structures formed by evaporation of organic compound solution to directly p-Si semiconductor substrate. It has been seen that the crystal violet organic dye thin film on the p-Si substrate has exhibited a good rectifying behavior. The barrier heights (BHs) and ideality factors of all devices have been calculated from the electrical characteristics. Although the diodes were all identically prepared, there was a diode-to-diode variation: the effective barrier heights ranged from 0.6 ± 0.1 to 0.8 ± 0.1 eV, and the ideality factor from 1.6 ± 0.4 to 3.5 ± 0.4. The barrier height versus ideality factor plot has been plotted for the OI devices. Lateral homogeneous BH was calculated as a value of 0.7 eV from the observed linear correlation between BH and ideality factor, which can be explained by laterally inhomogeneities of BHs. The values of barrier height and acceptor doping concentration yielded from the reverse bias C-V measurements ranged from 0.7 ± 0.1 to 1.3 ± 0.1 eV and from (4.7 ± 0.8) × 10¹⁴ to (8.1 ± 0.8) × 10¹⁴ cm⁻³, respectively. The mean barrier height and mean acceptor doping concentration from C-V characteristics has been calculated 1.0 eV and 5.9 × 10¹⁴ cm⁻³, respectively. It has been seen that the mean BH value of 0.7 eV obtained for the Al/methyl violet/p-Si contact is significantly larger than BH values of the conventional Al/p-Si Schottky diodes. Thus, modification of the interfacial potential barrier for metal/Si diodes has been achieved using a thin interlayer of the methyl violet organic semiconductor; this has been ascribed to the fact that the methyl violet interlayer increases the effective barrier height by influencing the space charge region of Si.     

Preparation of organic/inorganic hybrid nanocomposites by ultraviolet irradiation and their packaging applications for organic optoelectronic devices

By ultraviolet (UV)-assisted synthetic procedure, we have successfully prepared several UV curable organic/inorganic hybrid nanocomposites with excellent gas barrier capabilities, moderate hardness, and good adhesive strength. The experimental results reveal that the physical properties of nanocomposites depend on their chemical structures. Therefore, introduction of silicone and polyurethane (PU) into the Acrylics backbone dramatically raises the adhesive strength as well as refractive index and lowers the gas penetration. Furthermore, we have also applied lab-made nanocomposite g for the encapsulation of organic optoelectronic devices such as OLEDs, flexible OLEDs, and organic solar cells. With the package of lab-made nanocomposite g, the organic optoelectronic devices effectively resist the entry of moisture and oxygen in the air, extending the lifetimes.     

High-performance self-powered photodetector based on organic/inorganic hybrid van der Waals heterojunction of rubrene/silicon

Organic/inorganic hybrid van der Waals heterostructure with an atomically abrupt interface has attracted great research interests within the field of multifunctional electronic and optoelectronic devices. The integration of organic rubrene films with inorganic Si semiconductors can avoid the atomic mutual-diffusion at the interface, and provide the possibility of forming two-dimensional van der Waals heterojunction accompanied with the type-II energy band alignment, due to the transfer behaviors of majority carriers at the interface. In this study, the high-quality rubrene/Si van der Waals heterostructure with an electronically abrupt junction was prepared, and a self-powered photodetector was then constructed based on this hybrid heterojunction. The photodetector demonstrated an excellent switching response to the 1064 nm monochromatic light with large on/off current ratio of 7.0×10~3, the maximum photocurrent of 14.62 m A, the maximum responsivity of 2.07 A/W, the maximum detectivity of 2.9×10~(11) Jones, and a fast response time of 13.0 μs. This study offers important guidance for preparing high-quality rubrene/Si hybrid van der Waals heterostructure with desirable band alignment, and the designed heterojunction photodetector has an important application prospect in the field of multifunctional optoelectronics.     

Characterization of hybrid organic and inorganic functionalised membranes for proton conduction

Titanium zirconium phosphate and organic polymer hybrid (poly-vinyl alcohol, (3-glycidoxypropyl)-trimethoxysilane and ethylene glycol) based membranes were investigated for their potential application as proton conductors. The hybrid materials were characterized by XRD, FTIR, SEM, TGA and impedance spectroscopy analysis. It was found that embedding of functionalised inorganic particles (TiZrP) into composite polymer matrix allowed for some crystallinity formation, and cross-linking of hydroxyl groups during annealing or reactions within the organic and inorganic phases during synthesis. A complex structure was formed, as many FTIR peaks were masked by more defined peaks assigned to P–O–R bonds. The high concentration of phosphorus in the TiZrP (1:1:9 molar ratio) samples resulted in more hydrophilic particles. This was further reflected in the hybrid membranes as the water losses increased from 13 to 25 wt.% as a function of the TiZrP content changing from 10 to 50 wt.% in the final hybrid membrane, respectively. As a result, proton conductivity increased by two to three orders of magnitude from blank (organic phase only) membranes (2.61 × 10^− 5 S cm^− 1) to TiZrP hybrid membrane (2.41 × 10^− 2 S cm^− 1) at 20 °C. Proton conduction changed as a function of temperature and the Ti1Zr1P9 particles content, mainly attributed to the membrane ability to retain water, thus complying with the Grotthus mechanism.     

有机电致蓝光器件激发YAG∶Ce荧光粉光谱特性研究

模拟无机大功率白光LED由蓝光芯片激发荧光粉形成白光的发光方式,基于有机电致蓝光器件激发黄色的YAG∶Ce荧光粉来实现全色器件.采用真空蒸镀法,制备了ITO/2T-NATA(30 nm)/AND ∶ TB-Pe(50 Wt％,40 nm)/Alq3 (100 nm)/LiF(1 nm)/Al(100 nm)的蓝光器件,...     

Recent advances in organic,inorganic, and hybrid thermoelectric aerogels

The thermoelectric(TE)materials and corresponding TE devices can achieve direct heat-to-electricity conversion,thus have wide applications in heat energy harvesting(power generator),wearable electronics and local cooling.In recent years,aerogel-based TE materials have received considerable attention and have made remarkable progress because of their unique structural,electrical and thermal properties.In this review,the recent progress in both organic,inorganic,and composite/hybrid TE aerogels is systematically summarized,including the main constituents,preparation method,TE performance,as well as factors affecting the TE performance and the corresponding mechanism.Moreover,two typical aerogel-based TE devices/generators are compared and analyzed in terms of assembly modes and output performance.Finally,the present challenges and some tentative suggestions for future research prospects are provided in conclusion.     

Numerical calculation of the spectral bandwidth of optical parametric amplification in hybrid organic/inorganic planar waveguide

The spectral bandwidth of three-wave-mixing optical parametric amplification has been investigated in a simple hybrid polymer/ion exchanged planar optical waveguiding structure. A nonlinear polymer is deposited on the top of a glass substrate with a waveguide realized by the ion-exchange technique. The spectral bandwidth is determined by expanding the wave-vector mismatch in a Taylor series and retaining terms through second order. The relation between parametric bandwidth and gain bandwidth is clearly defined.     

SrS:Ce/ZnS:Mn-A di-band phosphor for near-UV and blue LED-converted white-light emitting diodes

The SrS:Ce/ZnS:Mn phosphor blends with various combination viz 75:25, 50:50 and 25:75 were assign to generate the white-light emission using near-UV and blue-light emitting diodes (LED) as an excitation source. The SrS:Ce exhibits strong absorption at 427 nm and the corresponding intense emission occurs at 480 and 540 nm due to electron transition from 5d(²D)−4f(²F_5/2, _7/2) of Ce³⁺ ion as a result of spin-orbit coupling. The ZnS:Mn excited under same wavelength shows broad emission band with λ_max=582 nm originates due to 3d (⁴G−⁶S) level of Mn²⁺. Photoluminescence studies of phosphor blend excited using near-UV to blue light confirms the emitted radiation varies from cool to warm white light in the range 430-600 nm, applicable to LED lightings. The CIE chromaticity coordinate values measured using SrS:Ce/ZnS:Mn phosphor blend-coated 430 nm LED pumped phosphors in the ratio 75:25, 50:50 and 25:75 are found to be (0.235, 0.125), (0.280, 0.190) and (0.285, 0.250), respectively.     

Highly stable Ag nanoparticles in agar-agar matrix as inorganic–organic hybrid

A novel synthesis of inorganic–organic hybrid films containing well dispersed and almost uniform size Ag nanoparticles in agar-agar matrix has been reported. The films are found to be highly stable for more than a year. The colloidal particles of Ag can be obtained in large quantities in the form of a film or in the gel form when dispersed in agar-agar or by dissolving in a suitable solvent as solution. Characterization has been done by UV–visible spectroscopy and TEM. The hybrid may be of interest to study third-order non-linear susceptibility.     

Top-gathering pillar array of hybrid organic–inorganic material by means of self-organization

Two-dimensional (2D) pillar arrays with submicrometer to micrometer repetitions have been fabricated from hybrid organic–inorganic material by mask lithography or multi-beam interference lithography. The type of array structure depends on structural parameters such as the pillar height, diameter and distance between neighboring pillars. Two kinds of periodic arrays, 2D arrays and ‘top-gathering’ arrays, can be obtained by controlling the structural parameters. In the top-gathering arrays, the pillars are gathered at the top by means of self-organization, and ‘top-gathering’ units composed of four pillars can be formed. PACS 68.35.Gy; 81.20.Fw; 82.50.-m     

Microheterogeneity in phenyl group modified inorganic/organic hybrid gels after aerosol drying or slow solvent evaporation

Sol-gel systems were prepared by co-hydrolysis and co-condensation of tetraethoxysilane (TEOS) and phenyltriethoxysilane (PhTES). The sols were transferred into silica gels by Evaporation Induced Self-Assembly (EISA) or Aerosol Assisted Self-Assembly (AASA) using a laboratory spray-dryer. The structural properties such as porosity and homogeneity/microheterogeneity of these different systems are compared by N(2) sorption measurements, thermal analysis (TG, DTG and DTA), (29)Si MAS NMR and (29)Si{(1)H} CP MAS NMR. The cross polarization of the AASA gels can be described with the conventional I-S dynamics of a homogeneous proton spin bath. The EISA gels are heterogeneous, and the I-I(*)-S model, or a bimodal I-S model, was employed for the simulation of CP dynamics. Microheterogeneities are observed by (1)H-(29)Si cross polarization on an EISA sample, whereas rapid drying (AASA) transfers the corresponding sol into homogeneous xerogels. The EISA gels are microporous after calcination at 923 K, and the AASA gels are dense.     

Electronic properties of 2D and 3D hybrid organic/inorganic perovskites for optoelectronic and photovoltaic applications

We herein investigate theoretically both 2D and 3D Hybrid Organic/inorganic perovskite crystal structures based on density functional theory (DFT) calculations and symmetry analyses. Our findings reveal the universal features of the electronic band structure for the class of lead-halide hybrids (R-NH \(_{3})_{n}\hbox {PbX}_{m}\) , where \((\mathrm{{n}}, \mathrm{{m}})=(2,4)\) and (1,3) respectively for 2D and 3D structures. Among those, the large spin-orbit coupling acting on the conduction band is shown to play a major role on the band gap of these materials. Moreover, this approach can easily be generalized to related layered and 3D hybrids, thus providing a clear-sighted inside in their electronic and optical properties.     

Microwave‐assisted synthesis of organic/inorganic hybrid nanocomposites and their encapsulating applications for photoelectric devices

UV curable organic/inorganic hybrid nanocomposites with high refractive indices, moderate hardness, good adhesive strength, and excellent gas blocking performances have been successfully rapidly synthesized by in situ microwave‐assisted heating process. We find that the chemical structures of polymer matrices influence the physical properties and addition of silicone and polyurethane (PU) into the acrylics backbone can further reduce the gas permeation and increase the adhesive strength as well as refractive indices. Moreover, lab‐made Silicone/PU/Acrylics I nanocomposites have also been utilized for the encapsulation of organic solar cells, LEDs, OLEDs, and flexible OLEDs. The experimental results demonstrate that they can effectively hinder the penetration of oxygen as well as moisture in the atmosphere into the photoelectric devices, consequently prolonging their lifetimes. Copyright © 2010 John Wiley & Sons, Ltd.