最新刊期
卷 35 ， 期 1 ， 2014
- 摘要：Zinc oxide (ZnO), as a typical wide bandgap (3.37 eV) semiconductor, has abstracted increasing interests in optoelectronics field. Its large exciton binding energy of 60 meV endows it with high radiative recombination efficiency, which is a unique advantage in light emitting and lasing devices. After more than a decade of developments, the thin film growth, doping and the device study have achieved much improvement. In this review, we introduce a part of results on the above aspects in the last five years. In these improvements, the ones achieved by the "973" project group (2011CB302000) are shown in detail. So far, their jobs cover hertero-and homo-epitaxy of thin film, interface and surface engineering, carrier transport, energy engineering, p-type doping and optoelectronics devices. They have realized the 2-D growth of thin film, epitaxial growth on silicon, solar blind UV detector, LED with dozens-hour continual-operating time, and lasing device with controllable mode. These advancements are expected to accelerate the process of practical applications of ZnO.关键词：ZnO;MgZnO;molecular beam epitaxy;surface/interface engineering;ultraviolet photodetector395|453|24更新时间：2020-08-12
- 摘要：MPO4:Eu3+,Bi3+/Tb3+ (M=La,Gd,Y) phosphors were synthesized by conventional solid state reaction. The structures of the samples were characterized by X-ray diffraction (XRD). The results indicate that YPO4 crystallizes is cubic structure while LaPO4 and GdPO4 are monoclinic structure. The difference between the emission spectra of YPO4:0.04Eu3+ and LaPO4:0.04Eu3+ indicates that the Eu3+ ions occupy nonequivalent sites in differrent material. The cubic structure is better for the luminescence of the doped RE ions than monoclinic structure. YPO4:0.04Eu3+ exhibits strong absorption at 394 nm and intense red emission. The same result can be obtained while the Eu3+ ions are changed into Tb3+ ions. The introduction of Bi3+ ions can significantly improve the photoluminescence properties of the phosphors.关键词：phosphor;phosphate;MPO4：Eu3+;Bi3+/Tb3+ (M=La;Gd;Y);crystal structure172|73|1更新时间：2020-08-12
- 摘要：Under different drive current and heat sink temperature, luminous performances as well as physical mechanisms were studied for both traditional phosphor-dispensing packaging white LED and blue light-converting hemisphere remote phosphor LEDs. With the increase of the heat sink temperature and the drive currents, the quantum efficiency and light conversion efficiency in the traditional phosphor-dispensing packaging white LED drop rapidly, which is responsible for the decrease of Y/B ratio (Yellow/Blue Ratio) and the apparent increase of CCT (correlated color temperature). However, the parameters of quantum efficiency, light conversion efficiency and CCT in blue light-converting hemisphere remote-phosphor packaging LEDs have little change under the same experimental conditions. In addition, the remote phosphor LEDs exhibit a batwing spatial luminous intensity distribution and the spatial Y/B ratio distribution is much more homogeneous compared with the traditional phosphor-dispensing packaging white LED.关键词：LED;phosphor;correlated color temperature (CCT);quantum efficiency;light conversion efficiency235|191|19更新时间：2020-08-12
- 摘要：Submicron sized Ca2.40Lu0.54ScMgSi3O12:0.06Ce3+ phosphor was prepared by sol-combustion (SC) method. The phase-forming, morphology, photoluminescence and thermal quenching properties of phosphor were investigated. The results confirm that the Ca2.40Lu0.54ScMgSi3O12:0.06Ce3+ phosphor can be prepared by SC method at 1ower temperature, and the morphology is much more uniform than the samples prepared by solid state (SS) method. Photoluminescence measurements show that the emission of the submicron sized Ca2.40Lu0.54ScMgSi3O12:0.06Ce3+ phosphor presents a ~10 nm red shift compared with the SS sample, and the thermal quenching of the submicron sized Ca2.40Lu0.54ScMgSi3O12:0.06Ce3+ phosphor is obviously weaker.关键词：LED;phosphor;submicron sized;thermal-quenching118|37|0更新时间：2020-08-12
- 摘要：Micro-structure of titanium dioxide (TiO2) layers were prepared by RF sputtering and Sol-gel on conductive glass FTO and porous alumina (AAO). The results show that there are great differences in the two kinds of TiO2. XRD diffraction and Raman scattering spectra illustrate that the crystal structure of TiO2 prepared by RF sputtering and Sol-gel are different after being calcinated at 500 ℃. On the conductive glass FTO, the TiO2 particles prepared by RF are distributed evenly and no cluster phenomenon, but the TiO2 prepared by sol-gel consist of small particle. On AAO templet, TiO2 sol particles are easy to flow in the hole due to the liquidity colloidal solution, which is contrary with the simple prepared by RF. The photocurrent experiment results show that the TiO2 prapered by sol-gel have better photocurrent performance.关键词：RF sputtering;sol-gel;AAO;TiO2/AAO94|71|0更新时间：2020-08-12
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Improvement of Performance of A Blue Organic Light-emitting Diode by Inserting Charge Control Layers
摘要：The performance of blue fluorescent organic light-emitting device (OLED) with N6,N6,N12,N12-tetrap-tolylchrysene-6,12-diamine (DNCA) as emitting layer (EML) was improved by inserting 2-methyl-9,10-di(2-napthyl)anthracene (MADN) 9,10-di(2-naphthyl)anthracene (ADN) as charge control layers (CCLs) into the device. For the optimum device with CCL structure of ITO/NPB (40 nm)/DNCA(15 nm)/MADN(3 nm)/DNCA(15 nm)/ADN(3 nm)/Bphen(30 nm)/LiF(0.8 nm)/Al(120 nm), the maximal current efficiency of 5.6 cd/A and the maximal luminance of 23 310 cd/m2 were achieved, which were enhanced by 70% and 87% comparing with the control device (CD) without CCLs, respectively. The performance improvement of the device can be attributed to the synergistic action (function) of the two CCLs. By utilizing the CCL structure, the original emitting zone can be separated into two parts by inserting MADN in the first EML, and the exciton formation region can also be broadened accordingly. Therefore, the excitons radiative process can be utilized to a great extent. Meanwhile, the holes can be effectively confined in the second EML by inserting ADN between the EML and ETL, which can prevent the excitons non-radiative process in the ETL so as to improve the device performance.关键词：blue OLED;charge control layers;exciton formation region154|91|2更新时间：2020-08-12 - 摘要：Yb3+/Er3+ co-doped 60P2O5-15BaO-10Al2O3-5ZnO-10R2O(R=Na, K) phosphorus based material with P2O5 as the principal ingredient were researched. The spectroscopic properties of the fiber material and the effect of Yb3+/Er3+ concentration ratios on the spectral properties were researched. When Er3+ concentration is 9.100×1019/cm3, Yb3+ concentration is 5.407×1020/cm3, and their optimum concentration ratio is 6:1, the largest stimulated emission cross section is obtained for 6.17×10-21 cm2. At the meantime,the fluorescence lifetime is 9.73 ms, full width half maximum (FWHM) is 53.16 nm, and the product of emission cross section and FWHM is 3.28×10-32 m3, which indicates this material has the best performance.关键词：active fiber;phosphorus glass;rare earth ion;spectroscopic properties105|112|2更新时间：2020-08-12
- 摘要：Indium interlayers with thickness of 0, 0.1, 0.5, 1 nm were deposited respectively before wurtzite InN was grown on silicon substrate by plasma-assisted molecular beam epitaxy (PA-MBE). X-ray diffraction (XRD) spectra, scanning electron microscope (SEM), absorption and photoluminescence (PL) spectra were adopted to analyze the influence of indium interlayer on the crystal and optical properties of InN. XRD and SEM results indicate that indium interlayer with the thickness of 0.5 nm can improve the morphology of InN epitaxial with larger crystalline grains and have a better crystal quality. Absorption and PL spectra show that the sample with 0.5 nm indium interlayer exhibits the smallest blue-shift of absorption edge, the narrowest FWHM of PL spectra and the best near-band-edge radiative recombination efficiency. In conclusion, indium interlayer with appropriate thickness does have a positive influence on the crystal and optical properties of InN grown on silicon substrate.关键词：InN;Si;MBE;indium interlayer82|154|0更新时间：2020-08-12
- 摘要：GaN-based green high-voltage (HV) light emitting diodes (LEDs) of 12 V were designed and fabricated. The optical and electrical parameters such as forward voltage, peak of wavelength, optical power, and luminous efficiency were investigated when the injection current varied from 3 mA to 50 mA at 25 ℃. The results show that the injection current has a great effect on the optical and electrical properties of the GaN-based high-voltage LED. When the current is 20 mA, the corresponding voltage is 14 V. With the increasing of the injection current, the blue-shift of LED peak wavelength reaches 2 nm. In addition, the optical power increases approximately linearly with the current increasing. The luminous efficiency decreases 61% when the injection current increases from 3 mA to 20 mA, and decreases 39% when the injection current increases from 20 mA to 50 mA. It indicates that the luminous efficiency decreases more slowly when the high-voltage LED is driven by large current. These results will have a certain reference value for the improvement and optimization of GaN-based high-voltage LEDs.关键词：GaN-based high-voltage light emitting diode;injection current;forward voltage;peak wavelength;luminous efficiency98|240|1更新时间：2020-08-12
- 摘要：Organic thin-film transistors (OTFTs) were prepared with inkjet-printed 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) as the active semiconducting layer. Poly(4-vinylphenol) (PVP) was spin-coated on the surface of SiO2 substrates as the surface modification layer to improve film morphology of the semiconductor. The source and drain electrodes were thermally eva-porated through a metal mask to complete the OTFTs with a bottom-gate top-contact (BGTC) structure. Compared with the TIPS-pentacene films inkjet-printed on the controlled SiO2 substrate without PVP modification layer, the single-drop semiconductor films deposited on the PVP-modified substrate show much reduced coffee-ring effect and therefore better film uniformity, while large-area films with rectangular pattern printed with overlapping multi-drop shows larger grain size and the corresponding OTFTs also exhibits enhanced field-effect mobility. The average field-effect mobility of the inkjet-printed film on the PVP-modified substrate was as high as 0.065 cm2·V-1·s-1, while the average field-effect mobility of the semiconductor directly printed on the SiO2 substrate was merely 0.02 cm2·V-1·s-1.关键词：organic semiconductor;organic thin-film transistor (OTFT);inkjet printing;surface modification;insulating polymer123|52|3更新时间：2020-08-12
- 摘要：The influence of the air hole filling factor on the frequency shift of depolarized guided acoustic Brillouin scattering in photonic crystal fibers with various structural parameters was presented. The dependence of Brillouin frequency shift on Brillouin scattering efficiency was investigated. The results indicate that the Brillouin frequency shift decreases with the air hole filling factor increasing. For a given lattice pitch or core diameter, the influence of the air hole filling factor on frequency shift of the higher order torsional-radial mode is more sensitive, and the scattering efficiency of the depolarized guided acoustic Brillouin scattering increases with the Brillouin frequency shift increasing.关键词：depolarized guided acoustic wave;photonic crystal fiber;brillouin frequency shift;Brillouin scattering efficiency118|154|1更新时间：2020-08-12
- 摘要：The molecularly imprinted photonic hydrogels (MIPH), based on the combination of photonic crystal and molecular imprinting technique, was prepared with Bisphenol A as template molecules, methanol as solvent, methacrylate and acrylamide as double functional monomer, ethy-lene glycol dimethyl methacrylate as cross-linked, 2,2-diethoxyacetophenone as photoinitiator. When the molecular imprint photonic crystal film is soaked in bisphenol A buffer solution, peak wavelengths of Bragg diffraction will red-shift 36 nm with the concentration increasing from 10-10 mol/L to 10-3 mol/L. The color changes can be distinguished by bare eye. More importantly, the color changing is not influenced by the ionic strength and other structure analogue molecules like ferulic acid, salicylic acid and hydroquinol.关键词：bisphenol A;molecularly imprinted;inverse opal photonic crystal224|124|2更新时间：2020-08-12
- 摘要：A novel fluorescent probe (FP) for detecting Fe3+ was synthesized from rhodamine B, ethylenediamine and glyoxal. Its molecule structure of FP was characterized by 1H NMR and MS, and its fluorescent properties of FP in detecting Fe3+ and other different metal ions were investigated by fluorescent spectroscopy. The experimental results show that FP has a higher selective recognition for Fe3+ in CH3OH, and other metal ions, such as Al3+, Pb2+, Cu2+, Cd2+, Mn2+, Hg2+, Mg2+, Ca2+, K+ and Na+, have no effects on its recognition for Fe3+. The complexation ratio of FP/Fe3+ is l:3 from the method of Jobs plot by UV-Vis spectroscopy. When the concentration of Fe3+ is 4×10-4~5×10-3 mol/L, there is a good linear relationship between the fluorescence intensity of FP and the concentration of Fe3+, and the linear correlation coefficient is 0.995 3. The analysis reveals that FP can be used as a fluorescent sensor for the selective detection of Fe3+.关键词：fluorescent probe;rhodamine B;glyoxal;Schiff-base;Fe3+132|91|5更新时间：2020-08-12
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