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The Natural Forest Protection Program, the Sloping Land Conversion Program and the Desertification Combating Program around Beijing and Tianjing have been gradually launched since 1998 for ecosystem restoration. A large number of rural households have been enrolled in these programs, and the Government of China has designed different polices for these programs, such as subsidies and forbidden or restricted uses. How and how much these programs and policies have affected rural households’ inequality are urgent questions to be answered. The paper used a unique panel data of 1458 sample rural households from 15 counties in China to examine the direct and overall contributions of the Key Priority Forestry Programs (KPFPs) to rural households’ total income inequality. A fixed-effects model was used to estimate the impact of the KPFPs on land-based income and off-farm income. Our empirical results indicate that the direct contribution and overall (including direct and indirect) contribution have experienced a inverted U-shape. Specifically, the overall contributions of the KPFPs’ subsidies to income inequality were less pronounced than that of the direct effects. Furthermore, both the direct contributions and overall contributions to total income inequality changed over time during the study period and differed from one county to another.

With fiber-reinforced Polymers (FRPs) widely used in aircraft, design and analysis of the mechanical performance and stability of structures and parts made of FRPs with various open-holes become very important. Currently, accurately predicting the failure patterns and ultimate strength of open-hole FRP structures remains very challenging. In this paper, a three-dimensional progressive damage model based on Puck's criterion on unidirectional FRP laminates has been developed. More importantly, a scaling algorithm that can differentiate the shear deformation modes and automatically modify the shear toughness has been proposed and implemented in the model. With this modified shear damage evolution law, our model accurately estimates the tensile strengths and captures the failure pattern of carbon fiber reinforced polymer (CFRP) panels consist of different stacking schemes with large open-holes in the middle. Furthermore, our model results point out that in panels of [ ± 45 ] 5 stacking scheme the inter-laminar stresses, although relatively small in magnitude, have a significant influence on the damage initiation locations.

Key Clinical Message A 53‐year‐old man presented with heart palpitations while swallowing. Electrophysiologic study (EPS) and immunohistochemical results of his esophageal leiomyoma suggested that swallowing‐induced atrial tachycardia is related with neural reflex. S100‐immunopositive nerve fibers are demonstrated sympathetic nerves which possibly explain the mechanism. Metoprolol tartrate tablets are effective in our patient.

In this paper, we successfully demonstrated high color rendering index (CRI) and color stable white organic light-emitting diodes (WOLEDs) based on a hole-type single-host double emissive layer (EML) structure. By combining the yellow phosphorescent emission with the blue monomer and red excimer emission of platinum [1,3-difluoro-4,6-di(2-pyridinyl)benzene]chloride (Pt-4), the devices exhibited a maximum CRI of 93, which was attributed to the perfect spectrum complement and the relative intensity adjustment of each emission peak. Meanwhile, the WOLEDs were very stable and showed a slight color coordinate shift of (±0.007, ±0.004) over a wide range of driving voltages from 4 to 10 V. The use of the double EML structure effectively confines the exciton generation zone in the Pt-4 EML, thus, the white-light emission comes from the energy transfer from host to Pt-4 and then to yellow phosphor, which is less affected by the driving conditions.

We reported on the electrical and surface characteristics of radio frequency (rf) AlO x film and their applications in InGaZnO-based thin film transistors (TFTs). By optimizing the rf power, AlO x film with the low leakage current density and smooth surface was obtained. The leakage current density for the 180 W AlO x film was observed to be ∼2.0 × 10 −9 A/cm 2 at electrical field strength of 2 MV/cm. The root mean square (rms) roughness of 180 W AlO x film was about 1.36 nm. InGaZnO-TFTs with different AlO x insulators were fabricated. The InGaZnO-TFT with 180 W AlO x insulator exhibits a field-effect mobility of 6.9 cm 2 /V s, a threshold voltage of 4.2 V, an on/off ratio of 2.7 × 10 7 , and a much smaller V th shift of 6.6 V for 20 V bias stress duration of 10,800 s. The improvement of InGaZnO-TFT with 180 W AlO x film is attributed to smooth surface of AlO x film and smaller trap charges. The results indicate that AlO x is a promising candidate insulator for InGaZnO-TFTs.

Objective: To clarify whether hyperthyroidism (HT) itself confers an additional effect on the hypercoagulable state and the risk of ischemic stroke among patients with hyperthyroid atrial fibrillation (AF). Methods: We prospectively evaluated plasma D-dimer levels and thromboembolic events among three groups of patients (hyperthyroid AF, n = 62; nonthyroid AF, n = 107, and HT without AF, n = 100). Plasma D-dimer levels were used to evaluate the hypercoagulable state. Results: The D-dimer level was significantly higher in patients with hyperthyroid AF than in nonthyroid AF (0.66 ± 0.06 vs. 0.34 ± 0.02 mg/l, p < 0.001) and HT without AF (0.66 ± 0.06 vs. 0.27 ± 0.02 mg/l, p < 0.001). During a 3-year follow-up, patients with hyperthyroid AF had a significantly higher incidence of ischemic stroke compared with patients with nonthyroid AF (hazard ratio, HR: 3.2, 95% confidence interval, CI: 1.01-5.59, p = 0.04). Cox regression analysis revealed that age (HR: 2.5, 95% CI: 1.01-1.21, p = 0.05), CHADS2-VAS score (HR: 5.5, 95% CI: 1.51-7.43, p = 0.01) and anticoagulation (HR: 0.45, 95% CI: 0.07-0.54, p = 0.01) were independent predictors of risk for the occurrence of ischemic stroke. Conclusions: The present study suggests that HT may enhance the hypercoagulable state and the risk of ischemic stroke in patients with AF.

Over the past two decades, China has undertaken unprecedented forest programs in an effort to restore damaged ecosystems and increasing farmers’ income. Using survey results of 2070 rural households in 15 counties of six provinces, we estimate the effects of China's Priority Forest Programs (PFPs) on rural households’ income mobility. The effects of the area enrolled in the PFPs on rural households are mixed. It appears that larger area enrolled in the Industrial Timber Plantation Program and the Sloping Land Conversion Program pushed up rural households’ income mobility, whereas greater area enrolled in the Natural Forest Protection Program constrained their income mobility, and the size of enrollment in the Desertification Combating Program around Beijing and Tianjin and the Shelterbelt Development Program in the Three-North Regions and the Yangtze River Basin seem to have little effect on rural households’ income mobility.

White organic light-emitting devices (WOLEDs) with enhanced current efficiency and negligible color shifting equipped with an internal color conversion layer (CCL) were fabricated. They were attained by embedding a single layer of silver nanoclusters (SNCs) between the CCL and light-emitting layer (EML). The simultaneous enhancement of the photoluminescence (PL) of the CCL and electroluminescence (EL) of the EML were realized by controlling the thickness and size of the SNCs to match the localized surface plasmon resonance spectrum with the PL spectrum of the CCL and the EL spectrum of the EML. The WOLED with optimal SNCs demonstrated a 25.81% enhancement in current efficiency at 60 mA cm-2 and good color stability over the entire range of current density.

We developed high color rendering index (CRI) white organic light emitting diodes (WOLEDs) by the incorporation of yellow or green fluorescence emission located between the monomer and excimer emission of platinum [1,3-difluoro-4,6-di (2-pyridinyl) benzene]chloride (Pt-4). The devices comprising yellow or green fluorescence emission exhibited a maximum CRI of 92 and 94, respectively. Meanwhile, the devices showed excellent chromatic stability and low efficiency roll-off. We attribute the high CRI to the perfect spectrum complement and the relative intensity adjustment between two emission layers (EMLs). The mechanism of triplet excition confinement plays a crucial role in the suppression of chromaticity shifting and efficiency roll-off.

The thin-film transistors (TFTs) with InGaZnO active layer with different oxygen partial pressures are fabricated by radio frequency sputtering. The influence of the oxygen partial pressure on the density of states (DOS) for InGaZnO-TFT is investigated by using temperature-dependent field-effect measurements. It indicates that the DOS become smaller with increasing oxygen partial pressure. The results are verified by the threshold voltage shift of InGaZnO-TFT with different oxygen partial pressures. The trend of the variation of DOS is consistent with that of the threshold voltage shift for InGaZnO-TFT. Thus, the gate bias instability is attributed to the charge trapping mechanism based on DOS. Therefore, this work offered a brief and accurate method to calculate DOS for demonstrating the bias stability of transistor.

This paper demonstrates the influence of temperature, exciton concentration, and electron transportation layers on the excimer emission of a novel deep-blue material: 4,4′-bis(4′′-triphenylsilyl) phenyl-1,1′-binaphthalene (SiBN), by studying the photoluminescence and electroluminescence spectra of SiBN-based film. We have further developed sunlight-like and warm-light white organic light-emitting diodes (WOLEDs) with high efficiency and wide-range spectra, using SiBN and bis(2-phenylbenzothiozolato-N,C2′)iridium(acetylacetonate) (bt2Ir(acac)) as the blue excimer and yellow materials, respectively. The resulting device exhibited an excellent spectra overlap ratio of 82.9 % with sunlight, while the device peak current efficiency, external quantum efficiency, and power efficiency were 18.5 cd/A, 6.34 %, and 11.68 lm/W, respectively, for sunlight-like WOLEDs.

PURPOSE: To evaluate the feasibility of femtosecond laser–induced lenticule transplantation in the rabbit cornea and to observe the relative histologic characteristics of corneal tissue and nerve repair after transplantation. METHODS: Eight healthy, purebred, New Zealand white rabbits underwent femtosecond laser small-incision lenticule extraction (SMILE) surgery in the right eye. Lenticules were inserted into a femtosecond laser–created corneal stromal pocket in the left eye, which was defined as femtosecond laser corneal lenticule transplantation. Postoperative observation and examination were completed to evaluate the surgery. RESULTS: In the early postoperative period, inflammation of the cornea was noted, tissue around the lenticule was edematous, and cells were activated. Tissue edema remained at postoperative day 10. By 1 month, edema had resolved, activated cells gradually became quiescent, and nerve fiber regeneration was observed. By 3 months, the lenticule integrated into the recipient cornea, extracellular matrix gradually cleared, and thicker nerve fibers were noted. By 6 months postoperative, morphology and distribution of the corneal stromal fibers were close to normal, and the number of nerve fibers was reduced. CONCLUSIONS: Femtosecond laser corneal lenticule transplantation in rabbits is feasible, as the lenticule was shown to thrive and integrate with the recipient stroma. Nerve regeneration begins after 1 month.

We have fabricated indium–gallium–zinc (IGZO) thin film transistor (TFT) using SiO x interlayer modified aluminum oxide (AlO x ) film as the gate insulator and investigated their electrical characteristics and bias voltage stress. Compared with IGZO-TFT with AlO x insulator, IGZO-TFT with AlO x /SiO x insulator shows superior performance and better bias stability. The saturation mobility increases from 5.6 cm 2 /V s to 7.8 cm 2 /V s, the threshold voltage downshifts from 9.5 V to 3.3 V, and the contact resistance reduces from 132 Ωcm to 91 Ωcm. The performance improvement is attributed to the following reasons: (1) the introduction of SiO x interlayer improves the insulator surface properties and leads to the high quality IGZO film and low trap density of IGZO/insulator interface. (2) The better interface between the channel and S/D electrodes is favorable to reduce the contact resistance of IGZO-TFT.

We fabricated the indium-gallium-zinc oxide (IGZO) thin film transistor (TFT) with reactive sputtered SiOx as passivation layer, and investigated the role of the SiOx passivation layer in the IGZO-TFT under gate bias stress. The bias stability of IGZO-TFT with passivation layer is much better than that of IGZO-TFT without passivation layer. After applying positive bias stress of 20 V for 10000s, the device without passivation layer shows a larger positive Vth shift of 7.3 V. However, the device with passivation layer exhibits a much smaller Vth shift of 1.3 V. It suggests that Vth instability is attributed to the interaction between the exposed IGZO back surface and oxygen in ambient atmosphere during the positive gate voltage stress. The results indicate that reactive sputtered SiOx passivation layer can effectively improve the bias stability of IGZO-TFT.

A copper phthalocyanine (CuPc) organic semiconductor is capped onto an amorphous indium–gallium–zinc-oxide (InGaZnO) thin film transistor (TFT) to enhance the photosensitivity of InGaZnO-TFT. The CuPc organic semiconductor is served as a light absorption layer and forms a p – n junction with the InGaZnO film. After 60 s white light illumination, light responsivity ( R ) of InGaZnO-TFT with a CuPc light absorption layer reaches a value of 148.5 A/W at a gate-source voltage ( V GS ) of 20 V, which is much larger than that (31.2 A/W) of the conventional InGaZnO-TFT. The results are attributed to the following mechanism. First, a CuPc layer is employed as the light absorption layer. Second, CuPc/InGaZnO p – n junction enables the injection of electron into InGaZnO film. Our results indicate that using CuPc as light absorption layer is an effective approach to improve the photosensitivity of InGaZnO-TFT.

The bias stress effect in pentacene thin-film transistors (TFTs) with and without MoO x interlayer was characterized. The device without MoO x interlayer showed a large threshold voltage shift of 5.1 V after stressing with a constant gate-source voltage of −40 V for 10000 s, while at the same condition, the device with MoO x interlayer showed a low threshold voltage shift of 1.9 V. The results can be attributed to the stable interface between MoO x /pentacene and small contact resistance change for the device with MoO x /Cu electrode. Pentacene-TFTs with MoO x interlayer showed a high field-effect mobility of 0.61 cm 2 /V s and excellent bias stability, which could be a significant step toward the commercialization of OTFT technology.

We demonstrated the tunable contact resistance in pentacene thin film transistor (TFT) by inserting an organic–inorganic hybrid interlayer between Au electrode and pentacene layer. The contact resistance of pentacene-TFT varies with concentration of pentacene-TFT varies with concentration of MoO x in organic–inorganic hybrid interlayer. MoO x in organic–inorganic hybrid interlayer. The contact resistance of the device with 55 wt% MoO x doped pentacene interlayer is about 7.8 times smaller than that of device without interlayer at the gate voltage of −20 V. Comparing the properties of pentacene-TFT without interlayer, the performance of the pentacene-TFT with 55 wt% MoO x doped pentacene was significantly improved: saturation mobility increased from 0.39 to 0.87 cm 2 /V s, threshold voltage reduced from −21.3 to −7.2 V, and threshold swing varied from 3.75 to 1.39 V/dec. Our results indicated that the organic–inorganic hybrid interlayer is an effective way to improve the performance of p -channel OTFTs.

A more steric hindrance pentacene derivative, 6,13-di-(3,5-diphenyl) phenylpentacene (PDT) is synthesized in this experiment. And this manuscript presents the red emission organic light-emitting devices based on tris-(8-hydroxy- quinolinato) aluminum (Alq 3 ) co-doped with 6,13-di-(3,5-diphenyl) phenylpentacene (PDT), and 5,6,11,12-tetraphenylnaphthacene (rubrene). By measuring and analyzing the intensity of red emission and Commission Internationale de l’Eclairage (CIE) coordinates of the devices with different rubrene concentrations and thicknesses of active layer, an optimized structure of [ITO/TPD(50 nm)/Alq 3 : 3mol%PDT:1mol%rubrene(60 nm)/Bphen(25 nm)/LiF/Al] is obtained. The experimental results suggest that rubrene assists energy transfer from Alq 3 to PDT in composite of Alq 3 :PDT:rubrene, which results in relatively pure red emission. A red emission with chromaticity coordinates ( x = 0.61, y = 0.37) is also obtained with the emitting layer of [Alq 3 :3 mol% PDT:1 mol% rubrene] within the driving current density range of 12–120 mA/cm 2 . A maximum luminance efficiency of 2.4 cd/A is measured at current density of 120 mA/cm 2 and high brightness of 2894 cd/m 2 .

Background Danon disease is an X‐linked dominant hereditary condition caused by mutations in the gene encoding lysosomal‐associated membrane protein 2 (LAMP2), leading to failure of lysosome binding to autophagosomes, accumulation of glycogen in the heart, and abnormal cardiac function. Methods We describe identification of a mutation in LAMP2, c.741+1G>T, in a family with Danon disease by whole exome sequencing. Results Pathology examination of patient skeletal muscle biopsy showed myogenic damage and autophagic vacuoles with sarcolemmal features (AVSF). Numerous autophagic vacuoles accumulated in muscle cells were detected by electron microscopy, indicating abnormal autophagy function. Conclusion The mutation did not result in loss of mRNA exons; rather, a 6‐nucleotide (two‐codon) insertion, where the latter was a stop codon, leading to early termination of LAMP2 protein translation. The resulting truncated protein lacks an important transmembrane domain, which will impair lysosome/autophagosome fusion, damage autophagy function, and result in the clinical manifestations of Danon disease.

Bottom-contact (BC) copper phthalocyanine (CuPc) thin film transistor with UV/ozone treated Au as a source/drain electrode was fabricated and the contact resistance was estimated from the transmission line method (TLM). Comparing the properties of OTFT with untreated Au electrode, the performance of the BC CuPc-TFT with the UV/ozone treated Au electrodes was significantly improved: saturation mobility increased from 4.69 × 10−3 to 2.37 × 10−2 cm2/V s, threshold voltage reduced from −29.1 to −6.4 V, and threshold swing varied from 5.08 to 2.25 V/decade. The contact resistance of the device with UV/ozone treated Au electrodes was nearly 20 times smaller than that of the device with untreated Au electrodes at the gate voltage of −20 V. This result indicated that using the UV/ozone treated Au electrode is an effective method to reduce the contact resistance. The present BC configuration with UV/ozone treated Au electrodes could be a significant step towards the commercialization of OTFT technology.

In this paper, energy relation between blue emissive layer (blue-EML) and red emissive layer (red-EML) in organic light-emitting diodes based on blue-emitting and red-emitting phosphorescent dopants, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (Firpic) and bis(2-(2′-benzo[4,5-α]thienyl)pyridinato-N,C3′)iridium(acetylacetonate) (Btp 2 Ir(acac)), was studied. Two phosphorescent dopants, Firpic and Btp 2 Ir(acac), were co-doped in the single emissive layer, and the results exhibit complete energy transfer from Firpic to Btp 2 Ir(acac). Then, Firpic and Btp 2 Ir(acac) were doped into blue-EML and red-EML, separately. By inserting 4,4′-bis(N-carbazolyl)biphenyl (CBP) spacer between blue- and red-EML, energy relation between blue- and red-EML was researched. The results of this work reveal that, CBP spacer may strengthen energy transfer between blue- and red-EML. The reason is that CBP triplets at blue-/red-EML interface can transfer their energies to both CBP molecules of red-EML and Firpic molecules of blue-EML in spacer-without devices, while CBP triplets in the spacer can transfer their energies only to CBP molecules of red-EML. Therefore, energy flow from blue- to red-EML is strengthened because of the avoidance of energy transfer from CBP triplets in the spacer to Firpic molecules of blue-EML, leading to the relative enhancement of red emission in CBP-spacer devices.

Three morphological structures of neodymium hydroxide (Nd(OH)3) nanoparticles, i.e. cube, sphere, and oval-like, have been synthesized in microemulsion systems. Calcination of the Nd(OH)3 nanoparticles with different morphologies at 900 °C in air yields neodymium oxide (Nd2O3) nanoparticles with the same morphological structures as those of their Nd(OH)3 precursors. The Nd(OH)3 nanoparticles are characterized by DSC–TGA, XRD and TEM, and the Nd2O3 nanoparticles by XRD and TEM. The morphological structures of the Nd(OH)3 and Nd2O3 nanoparticles are controlled via the variation of the molar ratio of H2O to CTAB (ω). Experimental results show that the stirring time has no effects on the morphological structures of the Nd(OH)3 nanoparticles, but rather has a significant impact on the sizes of the Nd(OH)3 nanoparticles under the same ω. Possible formation mechanisms of the morphological structure of Nd(OH)3 are proposed and discussed.

To date, numerous studies have employed single type nitrogen (N) addition methods in reporting influences of N deposition on soil extracellular enzymatic activities (EEA) during litter decomposition in forest ecosystems. As natural atmospheric N deposition is a set of complex compounds including inorganic N and organic N, it is essential for investigating responses of soil EEA to various mixed N fertilization. In a subtropical forest stand in Zijin Mountain, East China, various N fertilizers with different inorganic N and organic N ratios were added to soils monthly from 2008 to 2009. Samples were harvested from N fertilized and control plots every 4 months. Subsequently, six EEA were assayed. A laboratory experiment was also conducted simultaneously. Both field and laboratory experiments showed that various mixed N fertilizations revealed different influences on soil EEA. Acceleration of most soil EEA by mixed N fertilization was greater than that of single N fertilization. The majority of soil extracellular enzymes exhibited the highest activities under mixed N fertilization, with the ratio of inorganic N to organic N at 3:7. These results suggested that N type and ratio of inorganic N and organic N were important factors controlling soil EEA, and the 3:7 ratio of inorganic N and organic N may be the optimum for soil EEA.

Fluorescent red organic light-emitting devices (OLEDs) with narrow emission and negligible current-induced quenching by using a pentacene derivative of 6,13-di-(3,5-diphenyl)phenylpentacene (PDT) doped emitting system were demonstrated. With the incorporation of C 60 outcoupling layer, the PDT-based top-emitting OLED showed superior electroluminescence performances with Commission Internationale d’Eclairage color coordinates of (0.64, 0.36) and luminous efficiency of ∼3 cd/A. To clarify the actual energy transfer process in PDT-doped emitting system, the Forster’s radius was calculated. The results indicated that the energy transfer process is predominantly from the host of tris(8-hydroquinoline) aluminum to guest of PDT via the assistant dopant of 5,6,11,12-tetraphenylnaphthacene.

Influences of O 2 /Ar flux ratio (R) on surface morphology and structural evolution have been studied in the case of ZnO films deposited on glass substrates by radio-frequency (rf) magnetron sputtering. Results of atomic force microscopy (AFM), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) clearly indicate that the surface root-mean-square (rms) roughness, crystallinity, stress, and defects strongly depend on the R. At R =1/2, the crystallized ZnO film with highly c-axis orientation and highly smooth surface has been obtained. The implication of these results is that a moderate R is needed to realize high-quality ZnO film.

The current roll-off in organic light-emitting diodes has been studied by observing the current density versus voltage characteristics and spectra of single-layer and bilayer devices. Pumped by radiation sources of a variety of intensities, the current densities in a single-layer device decrease and spectra were shifted towards blue region. This is a result of the large amount of excess anion radicals that absorb the emitted photons. Using a bilayer device to balance the excess anion radicals is one of the methods to restrain the current roll-off.

Nanometer-scale α -Fe2O3 particles are prepared by the thermo-decomposition of a new Fe3 + complex with o-nitrobenzoic acid as a ligand. The structure and properties of the Fe3 + complex are revealed and confirmed by FT-IR and TG-DTA, and the α -Fe2O3 nanoparticles are characterized by TEM, XRD, and BET. The results indicate that the yield and dispersion of the α -Fe2O3 nanoparticles can be controlled via an addition of sodium dodecylsulfonate as a surfactant and under certain experimental conditions.

We demonstrated that the electrical properties of pentacene-thin film transistors with low-cost Cu electrodes can be enhanced by inserting a thin MoO x interlayer layer between pentacene and Cu source/drain (S/D) electrodes. In comparison with the device having Cu-only electrodes, the performance of the device with MoO x /Cu electrodes was significantly improved. The saturation mobility increased from 0.13 to 0.61 cm 2 /V s, threshold voltage reduced from −14.5 to −7.3 V, on/off ratio shifted from 8.9 × 10 5 to 1.6 × 10 6 and threshold swing varied from 1.92 to 1.33 V/decade. The improvement was attributed to the reduction of contact resistance and the enhancement of hole-injection efficiency. The results suggest modification of Cu S/D electrodes is a simple and effective way to improve device performance and reduce the fabrication cost.

Top-emitting organic light-emitting devices (TOLEDs) with high efficiency and low driving voltage using silver–silver microcavity structure were demonstrated. With tris(8-hydroquinoline) aluminum as emission layer, the Ag–Ag based TOLED showed a maximum luminous efficiency of 9.21 cd/A which was much higher than conventional Ag–Al/Ag based TOLED (4.21 cd/A) and corresponding bottom-emitting OLED (3.77 cd/A). The Ag–Ag based TOLED also exhibited low driving voltage and thereby an enhanced power efficiency of 4.25 lm/W (at 40 mA/cm 2 ). The excellent performance of Ag–Ag based TOLED was attributed to the significant microcavity effect and efficient carrier injection from Ag electrode.

A new X-shaped solution-processible oligomer with a glass transition temperature of higher than 200 °C based on an anthracene derivative was prepared, and it showed good hole-transporting ability in organic light-emitting diodes (OLED). Such oligomer was also employed as the emitting layer to give the devices showing blue emission.

A new alternative copolymer composed of fluorene and quinoxaline units having benzothiadiazole groups in the side chain was prepared and used as a green emitter for polymeric light-emitting diodes to give a device emitting pure green color at about 520 nm with a chromaticity coordinate of (x = 0.32, y = 0.59), matching the NTSC 1979 standard green color (x = 0.31, y = 0.595) very well.

In this work, we report the preparation of the Sm2O3 nanoparticle precursors (Sm(OH)3) via a simple W/O microemulsion process, in which microemulsions of cetyltrimethylammonium bromide (CTAB)/alkanol/1-octane/Sm(NO3)3 aqueous solution were added into sodium hydroxide (NaOH) aqueous solutions. The Sm2O3 nanoparticles were then prepared by calcining the precursors at 900 degrees C. Particularly, DeltaG(c--i), which is the change in standard Gibbs free energy for transferring cosurfactant from the continuous phase to the microemulsion interface and can be used to estimate the thermodynamic properties of microemulsions, was determined using the dilution method. The effects of alkanol carbon chain length (1-pentanol, 1-hexanol, 1-heptanol and 1-octanol) and the reaction temperatures (298, 308, 318 and 328 K) on both DeltaG(c--i) and Sm2O3 nanoparticle size have been investigated. Specifically, the Sm2O3 nanoparticle size, when calcined at 900 degrees C, was found to be mainly controlled by DeltaG(c--i), and was thereby affected by the thermodynamic properties of microemulsions. The obtained products were characterized by DSC-TGA, XRD, TEM and UV-Vis. The results showed that DeltaG(c--i) decreased with the increase in both the length of alkanol carbon chain and the reaction temperature, and the average size of Sm2O3 nanoparticles decreased as DeltaG(c--i) decreased. The effect of microemulsion thermodynamic properties on Sm2O3 nanoparticle size reported here can provide some insights in controllable preparation of other rare earth oxide nanoparticles via the microemulsion route.

Organic thin film transistors (OTFTs) with different concentrations of tetrafluorotetracyanoquinodimethane ( F 4 -TCNQ) doped pentacene interlayer were fabricated. When a 2 wt% F 4 -TCNQ doped pentacene layer was incorporated between gold electrodes and a pentacene layer, the performance of the OTFT was significantly improved. The saturation mobility increased from 0.21 to 0.63 cm 2 / V s , the threshold voltage was reduced from −31.9 to −7.6 V, and the threshold swing varied from 5.09 to 2.40 V/dec as compared with an OTFT without interlayer. This improvement was ascribed to the reduction of the hole-injection barrier and contact resistance. Our results indicated that contact-area-limited doping is an effective way to improve OTFT performance.

We demonstrate p–i–n organic light-emitting diodes (OLEDs) incorporating an n-doping transport layer which comprises 8-hydroxy-quinolinato lithium (Liq) doped into 4′7-diphyenyl-1,10-phenanthroline (Bphen) as ETL and a p-doping transport layer which includes tetrafluro-tetracyano-quinodimethane (F 4 -TCNQ) doped into 4,4′,4″- tris (3-methylphenylphenylamono) triphenylamine (m-MTDATA). In order to examine the improvement in the conductivity of transport layers, hole-only and electron-only devices are fabricated. The current and power efficiency of organic light-emitting diodes have been improved significantly after introducing a novel n-doping (Bphen: 33 wt% Liq) layer as an electron transport layer (ETL) and a p-doping layer composed of m-MTDATA and F 4 -TCNQ as a hole transport layer (HTL). Compared with the control device (without doping), the current efficiency and power efficiency of Device C (most efficient) is enhanced by approximately 51% and 89%, respectively, while driving voltage is reduced by 29%. This improvement is attributed to the improved conductivity of the transport layers that leads to the efficient charge balance in the emission zone.

Electron injection and transport are key issues in organic light-emitting devices (OLEDs). In this letter, we successfully demonstrated the electron injection property which is usually characterized by electronic barrier height from aluminum cathode to tris(8-hydroquinoline) aluminum (Alq 3 ) or 4,7-diphyenyl-1,10-phenanthroline (BPhen) (the most common two electron-transport materials) by current–voltage ( J – V ) characteristics. The electronic barrier height of 0.66 eV at the Alq 3 /Al interface and that of 0.10 eV at the Alq 3 /LiF/Al interface was obtained, which is in good agreement with the experimental results investigated by ultraviolet photoelectron spectroscopy (UPS) by Mori et al. [Appl. Phys. Lett. 73 (1998) 2763]. The electronic barrier height of 0.83 eV at BPhen/Al interface and that of 0.098 eV at BPhen/Cs 2 O/Al interface was also demonstrated for the first time, suggesting Cs 2 O is a highly efficient electron-injection material (EIM) for BPhen. We proposed a simple and yet practical approach to estimate the electron-injection barrier-height at the organic–metal interface in OLEDs. The results were further explained by the dipole effect.

A novel composite electron injection layer ( c -EIL) composed of 8-hydroquinolatolithium (Liq) and cesium oxide (CsOx) was sandwiched between tris(8-hydroquinoline) aluminum (Alq3) and an Al cathode to enhance electron injection in organic light-emitting devices (OLEDs). Using this strategy, the luminous efficiency was enhanced by ∼22% and ∼31% at the current density of 20 mA/cm2 and 200 mA/cm2, respectively, and the power efficiency has been increased by ∼29% and ∼36% at the same current densities, as compared with the control device when the optimal composition of Liq(1 nm)/CsOx(1 nm) was employed. The enhancement of electron injection by incorporating c -EIL was further verified by electron-only devices and was explained by the dipole effect and a step barrier provided by the intermediate energy level of Liq interlayer. Our results strongly suggested that the c -EIL was an excellent choice to enhance electron injection and would surely contribute to stability of OLEDs since a better improvement in luminous and power efficiencies at higher current density was observed.

We demonstrated efficient red organic light-emitting diodes based on a wide band gap material 9,10-bis(2-naphthyl)anthracene (ADN) doped with 4-(dicyano-methylene)-2- t -butyle-6-(1,1,7,7-tetramethyl-julolidyl-9-enyl)-4 H -pyran (DCJTB) as a red dopant and 2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1 H ,5 H ,11 H -10(2-benzothiazolyl)quinolizine-[9,9 a ,1 gh ]coumarin (C545T) as an assistant dopant. The typical device structure was glass substrate/ITO/4,4′,4″-tris( N -3-methylphenyl- N -phenyl-amino)triphenylamine ( m -MTDATA)/ N , N ′-bis(naphthalene-1-yl)- N , N ′-diphenyl-benzidine (NPB)/[ADN:Alq 3 ]:DCJTB:C545T/Alq 3 /LiF/Al. It was found that C545T dopant did not by itself emit but did assist the energy transfer from the host (ADN) to the red emitting dopant via cascade energy transfer mechanism. The OLEDs realized by this approach significantly improved the EL efficiency. We achieved a significant improvement regarding saturated red color when a polar co-host emitter (Alq 3 ) was incorporated in the matrix of [ADN:Alq 3 ]. Since ADN possesses a considerable high electron mobility of 3.1 × 10 −4 cm 2 V −1 s −1 , co-host devices with high concentration of ADN (>70%) exhibited low driving voltage and high current efficiency as compared to the devices without ADN. We obtained a device with a current efficiency of 3.6 cd/A, Commission International d’Eclairage coordinates of [0.618, 0.373] and peak λ max = 620 nm at a current density of 20 mA/cm 2 . This is a promising way of utilizing wide band gap material as the host to make red OLEDs, which will be useful in improving the electroluminescent performance of devices and simplifying the process of fabricating full color OLEDs.

A new star-shaped polymer comprising of full fluorene units was synthesized by Suzuki polycondensation between an A3 type monomer and an AB type monomer. For comparison, a fluorene-based linear polymer was also prepared. The star-shaped polymer was soluble in common organic solvents and gave the number-average molecular weight, Mn, of more than 12,000 and the weight-average molecular weight, Mw, of exceeded 22,000. The polymer showed similar optical behavior both in solution and in the solid state. After an annealing process, the linear fluorene-based polymer showed an additional bathochromic emission at about 550 nm, whereas such red-shifted emission was fully eliminated for the fluorene-based star-shaped polymer. Cyclic voltammetry (CV) measurement of the polymer indicated that the polymer was reversible under p-doping.

This paper presents organic light-emitting diodes which generate white emission based on both perylene and rubrene doped in 9,10-di(2-naphthyl)anthracene (ADN). In this doping system, the blue dopant perylene not only emitted but also assisted the energy transfer from ADN to rubrene, which contributes to a lower doping concentration of rubrene. The optimal configuration of the device is ITO/TPD(50 nm)/ADN:0.5 wt% perylene:0.006 wt% rubrene(40 nm)/Bphen(25 nm)/LiF(1 nm)/Al. The maximum luminance of 11 665 cd/m2 at 14 V according to a luminance efficiency of 2.9 cd/A was obtained. A CIE color coordinate of (0.30, 0.37) at 4 mA/cm2 was also achieved.

A new X-shaped π-conjugated monomer comprising of fluorene units and anthracene units was synthesized, and it was used to fabricate the new X-shaped π-conjugated polymers and investigate the properties of the new polymers. Using different molar ratios between such monomer and a fluorene monomer gave three polymers that showed higher absolute PL quantum yields than the linear polyfluorene (PF) in the solid state. After thermal annealing at 200 °C for 4 h, the linear PF showed an additional bathochromic emission at about 550 nm, whereas such red-shifted emission was fully eliminated for the X-shaped polymers. The electroluminescent devices based on the X-shaped polymers with a configuration of ITO/PEDOT:PSS/polymer/LiF/Ca/Al displayed blue emission with low turn-on voltage and high brightness.