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In this study, ZnO nanotubes, ZnO/ZnS core-shell nanorods, and ZnO/ZnS nanotubes were fabricated. To fabricate different types of ZnO-based nanocomposites, the central area of the ZnO nanorods was etched by a KCl solution and the outward shell was sulfurized to form ZnS/ZnO shell structures. Surface morphologies and material properties of the various nanostructures were examined by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Transmission X-ray Microscopy (TXM). Multiple material characterizations including X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), and Photoluminescence (PL) were performed. Results indicate that larger surface areas and higher defect concentrations can be obtained by the etching of ZnO nanorods. ZnO/ZnS nanotubes formed by sulfurization roughen the shell surface and mitigate defects. Results indicate that ZnO and ZnO/ZnS nanotubes show promise for future sensing device applications.

ZnO/ZnS core-shell structures were hydrothermally grown on SiO2 substrates functioning as hydrogen gas sensing chips. Results indicate that a core-shell structure with an appropriate sulfurization period of 10 min had better H2 sensing performance than those of all other growth conditions. Furthermore, multiple material characterizations revealed that ZnS with a growth time of 10 min could form high-quality and good-adherent ZnS powders with moderate thickness attached to the ZnO nanorods. Because of their small size, portability, simple fabrication and high sensitivity, ZnO/ZnS core-shell based H2 gas sensors show promise for future H2 detecting applications.

Aggregation/disaggregation properties in organic/inorganic interfaces have been intensively investigated recently because modulation of the aggregation effect can enhance the fluorescent emission, facilitate light scattering and strengthen the material strength. In this study, bisindolo quinoxaline-tips (BIQ-TIPs) organic polymers dropped on ZnO nanorods (NRs) to form organic/inorganic hybrid photosensing materials. Multiple morphological and material characterizations reveal that as-deposited BIQ-TIPs polymers self-aggregated on ZnO NR surfaces. UV/VIS measurements and photoluminescence (PL) mapping indicate that the absorption spectra of ZnO NRs can be broadened by incorporating BIQ-TIPs on top of ZnO NRs. Furthermore, light photosensitive measurements indicate that BIQ-TIPs /ZnO NRs-based devices exhibited better UV sensing behaviors than ZnO NR-based devices. Interestingly, BIQ-TIPs /ZnO NRs still possessed moderate green light sensing capability while ZnO NRs and BIQ-TIPs only samples possessed no green light sensing capability. Owing to their compact size, facile fabrication, and versatility, BIQ-TIPs /ZnO NR devices show promise for integration with BIQ-TIPs analogue-based electronic devices and future broadband sensing and light-harvesting applications.

Most small molecule organic light emitting diode (SM-OLED) device structures are made in one layer using solution-based processing because the solution is usually a high dissolvent material that easily attacks the layer below it. We demonstrate a simple and reliable stamping technique for fabricating multi-solution process flexible white SM-OLEDs. The structure is anode/spin-hole injection layer/spin-emitting layer/stamping-electron transport layer/cathode. Poly(di-methyl silane) (PDMS) stamp is used for transferring electron transport layer. An intermediate ultraviolet-ozone surface treatment is introduced to temporarily modify the PDMS stamp surface. Then, the solution-based electron transport layer film can therefore be uniformly formed on top of the PDMS surface. After that the electron transport layer film on the PDMS stamp is transfer-printed onto the emitting layer with suitable heating and pressing. A solution-based processing is successfully established to efficiently fabricate flexible white SM-OLEDs. The SM-OLEDs were obtained at the current density of 20 mA/cm 2 , luminance of 1062 cd/m 2 , current efficiency of 5.57 cd/A, and Commission internationale de l'eclairage coordinate of (0.32, 0.35).

Reliability investigations were conducted after GaN-based LEDs were stressed in seawater vapour. Multiple electrical, optical, and material analyses on the fine nanostructures of the LED were examined. Results indicate that dark spots on the surface and etching trenches observed on the cross section might damage the quantum well and degrade LED performance. Dissolved sodium ions might diffuse and punch through the quantum well and be responsible for these spots and trenches.

ZnO/ZnS core-shell nanostructures were successfully synthesized on porous silicon substrates using hydrothermal methods. Multiple morphological and crystalline characterizations were performed on the structures. Results indicate that a uniformly grown ZnS shell with a thickness of around 10 nm could be observed on the cross-section of ZnO/ZnS core-shell structures. Furthermore, different crystalline phases and morphologies could be observed in selected area diffraction patterns between neighboring nanostructures. Material compositional analysis conducted by energy-dispersive X-ray spectroscopy indicate that varied nanostructure element compositions grew perpendicular to the substrate. ZnS/ZnO nanostructures on porous silicon substrates show promise for future optoelectronic and electronic device applications.

In this paper, the flexible white organic light-emitting diodes (WOLED) was fabricated on polyethylene naphthalate (PEN) with structure of ITO/EHI608 (75 nm)/HTG-1 (10 nm)/3% EB502:0.8% EY53 (5 nm)/3% EB502 (35 nm)/Alq3 (10 nm)/LiF (0.8 nm)/Al (150 nm) and was compared with glass substrate the same structure. It was seen that the performances of flexible and glass substrate are almost the same. The luminance, current efficiency, and CIE coordinates of flexible device is 6351 cd/m2, 12.7 cd/A, and (0.31, 0.38) at 50 mA/cm2, respectively. Then, an Al2O3/HfO2 film on polyethylene terephthalate (PET) was deposited using atomic layer deposition (ALD) as a thin film encapsulation layer have been described and compared, such as the characteristics of water permeability and lifetime of flexible WOLED. The results show that the PET/ALD film low value of about 0.04 g/m2d, and the PET film shows WVTR of about 3.8 g/m2/d. The lifetimes of PET/ALD and PET encapsulations are 840 min and 140 min, respectively. Simultaneous deposition of ALD film on PET film gave the lifetime of flexible WOLED is six times longer than device without ALD encapsulation.

Display Omitted Investigating PhOLEDs with different solvents and dopants concentrations.High efficiency white PhOLEDs induced by the electron transport/hole blocking material.To achieve efficient and low-cost small-molecule-based white PhOLEDs. In this study, white phosphorescent organic light-emitting diodes (PhOLEDs) have been demonstrated with small molecule by using solution processes. Spin-coating is employed as the way for deposition method. 4,4'-N,N'-dicarbazole-biphenyl (CBP) which is typical small molecule based ink is used for spin-coating method, and three phosphorescent dopants materials, Firidium(III) bis(4,6-difluoro phenyl)-pyridinato-N,C2'] picolinate (FIrpic), bis1-(phenyl) isoquinoline) iridium(III) acetyl acetonate (Ir(piq)2 (acac))], and iridium(III) tris(2-phenylpy-ridine) (Ir(ppy)3) were prepared. For spin-coating processes, various parameters properties were investigated including materials concentrations, solvents effect, and electron transporting materials to get high efficiency and white color of white PhOLED device. As a result, the precisely controlled solution processes could be a promising technology for solution process can be a good alternative of vacuum deposition technology.

In this research, complex emitting layers (EML) were fabricated using TCTA doping hole-transport material in the front half of a bipolar 26DCzPPy as well as PPT doping electron-transport material in the back half of 26DCzPPy. Blue dopant FIrpic was also mixed inside the complex emitting layer to produce a highly efficient blue phosphorescent organic light emitting diode (OLED). The hole and electron injection and carrier recombination rate were effectively increased. The fabricated complex emitting layers exhibited current efficiency of 42 cd/A and power efficiency of 30 lm/W when the luminance was 1000 cd/m 2 , driving voltage was 4.4 V, and current density was 2.4 mA/cm 2 . A white OLED component was then manufactured by doping red dopant [Os(bpftz) 2 (PPh 2 Me) 2 ] (Os) in proper locations. When the Os dopant was doped in between the complex emitting layers, excitons were effectively confined within, increasing the recombination rate and therefore reducing the color shift. The resulting Commission Internationale de L’Eclairage (CIE) coordinates shifted from 4 to 10 V is (Δ x =−0.04, Δ y =+0.01). The component had a current efficiency of 35.7 cd/A, a power efficiency of 24 lm/W, driving voltage of 4.6 V and a CIE x , y of (0.31,0.35) at a luminance of 1000 cd/m 2 , with a maximum luminance of 15,600 cd/m 2 at 10 V. Attaching an outcoupling enhancement film was applied to increase the luminance efficiency to 30 lm/W.

Hybrid white organic light emitting diodes (HWOLEDs) with fluorescence and phosphorescence hybrid structures are studied in this work. HWOLEDs were fabricated with blue/red emitting layers: fluorescent host material doped with sky blue material, and bipolar phosphorescent host emitting material doped with red dopant material. An electron blocking layer is applied that provides hole red guest emitter hole trapping effects, increases the charge carrier injection quantity into the emitting layers and controls the recombination zone (RZ) that helps balance the device color. Spacer layers were also inserted to expand the RZ, increase efficiency and reduce energy quenching along with roll-off effects. The resulting high efficiency warm white OLED device has the lower highest occupied molecule orbital level red guest material, current efficiency of 15.9 cd/A at current density of 20 mA/cm2, and Commission Internationale de L'Eclairage coordinates of (0.34, 0.39).

A mixed host emitting layer consisting of TCTA and 3TPYMB can greatly increase the efficiency of blue and white organic light emitting diodes (OLED). The hole transport material TCTA can be used as a buffer layer and a hole-transport host emitting layer. Combining TCTA with electron-transport 3TPYMB produces a mixed host emitting layer that can effectively confine the charge carrier within luminous layer. The electron transport layer 3TPYMB reduces electronic injection energy barriers, improves charge balance, and reduces drive voltage to 4.38 V with proper adjustment to optimum thickness. The luminous efficiency of blue light OLED mixed with FIrpic can reach 36.0 cd/A, 27.5 lm/W, and luminous efficiency of white light OLED mixed with Os tangerine adulterant can reach 36.1 cd/A, 26.4 lm/W.

The high haze light-trapping (LT) film offers enhanced scattering of light and is applied to a-Si:H solar cells. UV glue was spin coated on glass, and then the LT pattern was imprinted. Finally, a UV lamp was used to cure the UV glue on the glass. The LT film effectively increased the Haze ratio of glass and decreased the reflectance of a-Si:H solar cells. Therefore, the photon path length was increased to obtain maximum absorption by the absorber layer. High Haze LT film is able to enhance short circuit current density and efficiency of the device, as partial composite film generates broader scattering light, thereby causing shorter wave length light to be absorbed by the P layer so that the short circuit current density decreases. In case of lab-made a-Si:H thin film solar cells with v-shaped LT films, superior optoelectronic performances have been found (V oc = 0.74 V, J sc = 15.62 mA/cm 2 , F.F. = 70%, and η = 8.09%). We observed ~ 35% enhancement of the short-circuit current density and ~ 31% enhancement of the conversion efficiency.

The effect of the phosphor doping concentration on the optoelectronic characteristics of white phosphorescence organic light emitting diodes (PHOLEDs) was studied. A high efficiency white PHOLED was achieved using the unique efficiency properties of the red-emitting Osmium complex ([fptz = 3-trifluoromethyl-5-(2-pyridyl)-1,2,4-triazole, PPh2Me = phosphineligand]; Os(fptz)2(PPh2Me)2) combined with a well known efficient blue-emitting Iridium complex (bis[(4,6-difluorophenyl)-pyridinate-N,C2′; FIrpic]). The results demonstrate that with 2 wt% Os(fptz)2(PPh2Me)2 co-doped into the blue-emitting layer (10 wt% FIrpic doped into the host), the device can achieve a luminance efficiency of up to 40.4 cd/A (25.6 lm/W) with a good corresponding CIE coordinate (0.39, 0.40). The doping concentrations of the red-emitting and blue-emitting phosphors were adjusted to obtain a pure white light with a CIE coordinate of (0.368, 0.366). A high efficiency white PHOLED was achieved by optimizing the doping concentration of the red-emitting and blue-emitting complexes.

The characteristics of blue phosphorescent organic light-emitting diodes (PHOLEDs) with hole–buffer structure were investigated by inserting a hole transport-type host (TCTA) between the hole transport layer (HTL, TAPC) and emitting layer (EML, FIrpic:26DCzPPy). The hole transport-type host has lower hole mobility than the HTL material, which could effectively control the hole injection current from the HTL into the EML. Moreover, the hole injection barrier from HTL to EML can be reduced due to the suitable HOMO level of the insertion hole buffer layer, which results in the improvement of driving voltage. Furthermore, the power efficiency was improved by controlling the hole injection current through buffer layer thickness optimization. From the experimental results, an optimal blue PHOLED structure was established: ITO/TAPC(20 nm)/TCTA(25 nm)/FIrpic:26DCzPPy(20 nm)/3TPYMB(40 nm)/LiF(0.5 nm)/Al(200 nm). At luminance of 1000 cd/m2, the driving voltage decreased from 6.3 to 5.1 V and power efficiency enhanced from 6.7 to 13.5 lm/W could be observed.

UV-curable organic/inorganic hybrid composites with gas barrier and heat-dissipating capability have been successfully fast synthesized with microwave irradiation and utilized for the encapsulation of top-emitting organic light-emitting diodes (TEOLEDs). Experimental results manifest that lab-made organic/inorganic hybrid composites can effectively not only obstruct the invasion of moisture as well as oxygen in the atmosphere into the device but also lower the temperature of device. Therefore, the lifetimes of TEOLEDs with their encapsulation are 2.2 folds longer than those without encapsulation.

The lifetimes of organic light emitting diodes (OLEDs) have been successfully enhanced with the modulation of LiF thickness and the utilization of encapsulating adhesives, which have been successfully and quickly synthesized with UV irradiation. Experimental results demonstrate that LiF and lab-made encapsulating adhesives can block the invasion of moisture as well as oxygen in the atmosphere into the OLEDs so that the lifetimes of devices with their encapsulation are 18-folds longer than those without encapsulation.

We dissolved hole transport materials α-NPD and NPB in THF solvent, and spin-coated the α-NPD + THF or NPB + THF solution onto ITO anode surface to improve the luminance efficiency and lifetime of flexible fluorescent and phosphorescent organic light emitting diodes. Then the BCP and TPBi were employed as hole blocking layer (HBL) of phosphorescent device and its thickness was optimized. From the experimental results, the maximum luminance efficiency is 4.4 cd/A at 9 V of fluorescent device and 24.4 cd/A of phosphorescent device, respectively. Such an improvement in the device performance was attributed to the smoother surface and good contact between the interface of spin-coated HTL/ITO, the hole were effectively injected from the anode into the organic layer. And the deposited HTL can block excitons from diffusing into the anode to quench, thus improving the luminance efficiency and lifetime greatly.

UV-curable organic/inorganic hybrid nanocomposites have been successfully synthesized with polymer monomers (tetramethoxysilane (TMOS)/3-glycidoxypropyl-trimethoxysilane (GPTMS)) nano-fillers (silica/alumina), curing agents (bisphenol A (BPA)), and photoinitiators (triaryl sulfonium hexafluoroantimonate (TSH)) by in situ polymerization. Their thermal stability, coefficient of thermal expansion (CTE), adhesion strength, and gas barrier capability have also been investigated with thermogravimetry analysis (TGA), thermomechanical analysis (TMA), micro-computer universal testing machine and moisture penetration tests. Experimental results indicate that nano-fillers are completely homogeneously dispersed in the polymer matrices and the increase of nano-fillers in the nanocomposites causes the raise of decomposition temperature (Td) as well as gas resistance and the reduction of CTE as well as adhesion strength. Because lab-made organic/inorganic hybrid nanocomposites have been discovered to exhibit excellent gas barrier properties, we have also applied them for the encapsulation of organic light-emitting diodes (OLEDs) and flexible OLEDs. With lab-made nanocomposite d, the lifetimes of OLEDs and flexible OLEDs can be successfully lengthened to 92 and 36 h, respectively, whereas those of OLEDs and flexible OLEDs without encapsulation are 11 and 7 h, respectively. © 2008 Elsevier B.V. All rights reserved.

We have successfully prepared ultraviolet (UV) curable organic/inorganic hybrid nanocomposites with good thermal stability, moderate adhesion strength, and excellent barrier capability. In order to improve the gas blocking properties, the metal alloy (Invar) has been blended with lab-made organic/inorganic hybrid nanocomposites, dramatically not only raising the gas resistance but also reducing the shrinkage after UV curing. Moreover, we have also applied lab-made nanocomposite IV for the encapsulation of organic solar cells. The experimental results reveal that introduction of nanocomposite IV can effectively block the penetration of moisture as well as oxygen in the air into the devices and consequently promote the lifetime of organic solar cells.

In this work, color/luminance tunable organic light emitting diodes (OLEDs) (ITO glass/naphthyl phenyl benzidine (NPB; 80 nm)/4,4′-bis(diphenylvinylenyl)-biphenyl (ADS082BE; 35 nm)/1,3-bis[2-(2,2′-bipyridine-6-yl)-1,3,4-oxadiazo-5-yl]benzene (Bpy-OXD; 20 nm)/tris-[8-hydroxy-quinoline]aluminum (Alq 3 ; 50 nm)/lithium fluoride (LiF; 3 nm)/aluminum (Al, 80 nm)) with low turn-on voltage (3 V) and high luminance (4850 cd/m 2 at 9 V) have been successfully manufactured. The experimental results reveal that their electroluminescent properties (e.g. hue, luminescent intensity, etc.) can be modulated by the manipulation for the layer thickness of NPB/ADS082BE/Bpy-OXD and the applied voltages. In addition, we have also demonstrated lab-made UV-curable silicone-acrylate encapsulating resin exhibits excellent gas barrier capability so that the half-lifetimes of OLEDs reach 98 h whereas those without encapsulation are only 9 h.

In order to improve the luminance efficiency and flexibility of flexible organic light-emitting diodes (FOLEDs), a buffer layer was inserted between ITO and hole transport layer by spin coating. The buffer layer employed is poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), PEDOT:PSS/Teflon, N,N′-bis-(3-methylphenyl)-N,N′-bis-(phenyl)-benzidine (TPD) or bis[N-(1-naphthyl)-N-phenyl]benzidine (α-NPD). The TPD and α-NPD were first solved in chloroform before spin coating. When 40 nm PEDOT:PSS was employed as buffer layer, the FOLED luminance efficiency increased from 2 to 4 cd/A in comparison with the original device without any buffer layer. If the buffer layer was PEDOT:PSS/Teflon, the luminance efficiency increased slightly to 4.4 cd/A. If α-NPD buffer layer was used, the luminance yield of the FOLED could be increased to levels ⩾5.5 cd/A.

A top-emission inverted organic light-emitting diode (TEIOLED) was fabricated by using Al/AlN x layer as the cathode in the device structure of glass/Al/AlN x /AlQ 3 /NPB/MTDATA/Au/Ag, where AlN x ultra-thin layer was obtained from Al layer under 90 W microwave plasma treatments in Ar and N 2 mixed-gas environment. The N 2 /Ar ratio and plasma treatment time were adjusted to obtain the maximum luminance and efficiency of 1206 cd/m 2 and 0.51 cd/A, respectively, both at 17 V. The AlN x layer surface after plasma treatment was examined by atomic force microscope (AFM) to study the effects of surface roughness on the electroluminescent (EL) characteristics. The thickness of AlN x layer also affected EL results apparently.

The intrinsic and effective microwave surface impedances for a thin type-II superconducting film in the low and parallel DC magnetic field are calculated. We consider the case where the thickness of superconducting thin-film, d , is less than the penetration depth, λ L , and a row of vortices is present in the center plane of film. Firstly, we investigate the intrinsic surface impedance of a thin-film as a function of static field, film thickness, and radiation frequency as well. The contribution of the moving vortex chain to the intrinsic surface impedance will be numerically demonstrated. Next, we shall consider the resonant layered structure such as a superconducting thin-film deposited on a dielectric substrate and the resonant behavior in the effective surface resistance will then be examined in detail. The effect of vortex chain on the resonant phenomenon will be discussed and elucidated.

An unexpected enhancement in the variation of the diffraction intensity due to a predominant three-wave coherent interaction is observed in a four-beam X-ray diffraction. This intensity anomaly is found to result from the modification of mode excitation and the competition between coherent and incoherent interactions in the diffraction process. This finding opens up a new way of solving the phase problem.