超量子理论与半导体LED照明

追求LED照明系统有效光效的最大化,其实质是取得LED照明系统由电能转换成有效光量子的效率最大化。有效光量子表述为到达被照物体上的符合照明标准、生理健康、有超长寿命或满足设计寿命以及能营造舒适视觉环境等要求的光量子。实践证明应用威廉超量子理论生产的照明产品其光效可以比其他同类LED照明产品高出10%~60%。

三亚造礁石珊瑚虫黄藻光合作用效率的日变化规律

对海南三亚鹿回头珊瑚礁礁坪上块状类型的粗糙菊花珊瑚Goniastrea aspera、澄黄滨珊瑚Porites lutea和枝状类型的指状蔷薇珊瑚Montipora digitata的虫黄藻光合作用的有效光量子产量Fv/Fm′(Fv为可变荧光值,Fm′为光适应后的最大荧光值)开展了连续4d的现场监测,旨在了解珊瑚共生虫黄藻光合作用效率的日变化规律。结果表明:1)3种造礁珊瑚虫黄藻的Fv/Fm′与太阳辐射、温度呈现良好的负相关性,即太阳辐射越强、温度越高珊瑚虫黄藻的Fv/Fm′就越低,其中Fv/Fm′与太阳辐射的相关性高于与温度的相关性。2)珊瑚虫黄藻能够利用日照光进行光合作用,但存在一定的阈值,当光合有效辐射强度PAR<250μmol.(m2.s)?1时,珊瑚虫黄藻的有效光量子产量Fv/Fm′随着光强增强而增强,超过这一辐射强度时,珊瑚虫黄藻的Fv/Fm′迅速降低。3)从珊瑚虫黄藻的有效光量子产量Fv/Fm′的日变化看,粗糙菊花珊瑚虫黄藻的日变化幅度最小,澄黄滨珊瑚和指状蔷薇珊瑚的变化幅度接近。

套袋对‘马来西亚’蜜柚果实品质的影响

为研究套袋对‘马来西亚’蜜柚果实品质的影响,以不套袋为对照,用黄色纸袋、白色纸袋、白色无纺布袋、蓝色无纺布袋四种套袋材料对果实进行套袋处理。结果表明:四种套袋处理均起到保护果面,改善果实外观,提高商品果率的作用,黄色纸袋处理保护果面叶绿素的效果好于其它三种处理。四种套袋处理均显著提高了果实的可溶性固形物、维生素C含量,黄色纸袋处理效果优于其它处理。套袋处理对果实可滴定酸含量无显著影响。相同光强下,各种套袋处理的有效光量子效率均明显高于对照,黄色纸袋处理的有效光量子效率显著高于其它三种套袋处理,其它三种套袋处理间无明显差异。综合套袋对果实品质的影响,‘马来西亚’蜜柚宜用黄色纸袋套袋。

Neutron Star Magnetic Field as for Nonzero Photon Mass

We investigate the neutron star magnetic field by the relative mean-field theory, where the photon effective mass depending on baryon density of charged particles is nonzero. This field is produced by star itself, which is the function of baryon density. The result fits the observations.

Efficient Organic Multi-quantum Well Electroluminescent Devices Using Aluminum as Cathodes

Organic green light emitting devices(LEDs) with multi-quantum well(MQW) structure were fabricated. Aromatic diamine(TPD) was used as hole-transporting layer and potential barrier layer; Tris(8-hydroxyquinoline) aluminum(Alq 3) was acted as electron-transporting emitter and MQW green emitter. Air-stable aluminum(Al) was used as electron-injection contact. The influence of the thickness of potential barrier layer and the number of quantum well on the electroluminescent(EL) efficiencies of the devices was investigated. The organic LEDs with two quantum wells showed enhanced EL efficiencies. Maximum external quantum efficiency and brightness were 1.04 % and 7 000 cd/m 2, respectively.

Host Engineering for Red Electrophosphorescent Devices

In this paper, we demonstrate that controlled dopantoncentration is an essential issue for charge carriers transporting in red Phosphorescent Organic Light-Emitting Device （PHOLED）. Carriers transport via dopant molecules in the emitting layer with a single host, however, via both dopant and host molecules when their energy levels are well aligned. Conditions for reduced driving-voltage and enhanced efficiency of red PHOLED are obtained by employing a mixed host structure. A pure red PHOLED with color coordinates of （0.67, 0.33） has been realized by using only 4 wt% dopant, The device achieves 100 cd/cm2 at 2.9 V, with correspond- ing power efficiency of 9.3im/W and external quantum efficiency of 14.3%.

FeTe1-xSex monolayer films： towards the realization of high-temperature connate topological superconductivity

We performed angle-resolved photoemission spectroscopy studies on a series of FeTe_(1-x)Se_x monolayer films grown on Sr TiO_3.The superconductivity of the films is robust and rather insensitive to the variations of the band position and effective mass caused by the substitution of Se by Te.However,the band gap between the electron-and hole-like bands at the Brillouin zone center decreases towards band inversion and parity exchange,which drive the system to a nontrivial topological state predicted by theoretical calculations.Our results provide a clear experimental indication that the FeTe_(1-x)Se_x monolayer materials are high-temperature connate topological superconductors in which band topology and superconductivity are integrated intrinsically.

Thermally activated delayed fluorescence materialsensitized helicene enantiomer-based OLEDs:a new strategy for improving the efficiency of circularly polarized electroluminescence

A new strategy of thermally activated delayed fluorescence(TADF)material-sensitized circularly polarized luminescence(CPL)has been proposed for improving the efficiencies of fluorescent circularly polarized organic lightemitting diodes(OLEDs)(CP-OLEDs).Consequently,a pair of helicene enantiomers,(P)-HAI and(M)-HAI,were synthesized.The helicene enantiomers with the rigid helicalπ-skeleton had highly thermal and enantiomeric stabilities,and they also showed excellent photophysical properties,especially,intense mirror-image CPL activities with large luminescence dissymmetry factor(|g_(lum)|)values of about 6×10^(-3).Notably,the CP-OLEDs with the helicene enantiomers as emitters and a TADF molecule as sensitizer not only displayed better performance of lower turn-on voltage(V_(T))of 2.6 V,four-fold maxmium-external quantum efficiency(EQE_(max))of 5.3%,and lower efficiencies roll-off of 1.9%at 1000 cd m^(-2),than those of the devices without TADF sensitizer,but also exhibited intense circularly polarized electroluminescence(CPEL)with the electroluminescence dissymmetry factor(g_(EL))values of-2.3×10^(-3)and+3.0×10^(-3).Meanwhile,this study also represents the first thermally activated sensitized fluorescent CP-OLEDs with markedly enhanced efficiencies and intense CPEL.

Line-profile analysis of excitation spectroscopy in the even 4p^5(~2P_(1/2))nl′ [K′]_J(l′=1,3) autoionizing resonances of Kr

The even-parity autoionizing resonance series 4p^5np＇ [3/2] 1,2, [ 1/2] 1, and 4p^2nf＇ [5/213 of krytpon have been investigated by laser excitation from the two metastable states 4p55s [3/2]2 and 4p^55s＇ [1/2]0 in the photon energy region of 2900（P40000 cm^-1 at experimental bandwidth of -0.1 cm-1. The excitation spectra of the even-parity autoionizing resonance series, most of which are experimentally studied for the first time in this work, show typical asymmetric line shapes. Complementary information on level energies, quantum defects, line profile indices and resonance widths, resonance lifetimes and reduced widths of the auto- ionizing resonances are derived by Fano-type line-shape analyses of the experimental results. Results from this work indicate that the line profile index （q） and the resonance width （F） are approximately proportional to the effective principal quantum number （n＊）; the line separation of the 4p^5np＇ autoionizing resonances is also in good agreement with theoretical model

Liquid phase exfoliated boron nanosheets for all-optical modulation and logic gates

Boron nanosheets possess unique photoelectric properties, including photosensitivity, photoresponse,and optical nonlinearity. In this article, we show the interaction between light and boron nanosheets in which concentric rings formed in the far field, which attributed to the strong Kerr nonlinearity of boron nanosheets. Furthermore, the distortion, regulation and relationship between the Kerr nonlinearity and effective mass or carrier mobility of the diffraction rings of boron nanosheets have been investigated.Our work shows that the spatial self-phase modulation effect of boron nanosheets is indeed caused by nonlocal electronic coherence. In addition, we have implemented all-light modulation and all-light logic gates based on the prepared boron nanosheets. We believe that our results will provide a powerful demonstration of nonlinear photonic devices based on boron nanosheets and a reference for photonic devices based on two-dimensional materials.

Donor Binding Energy in GaAs/Ga_(1-x) Al_xAs Quantum Well:the Laser Field and Temperature Effects

Based on the effective-mass approximation theory and variational method, the laser field and temperature effects on the ground-state donor binding energy in the GaAsflGa1-x AlxAs quantum well （QW） are investigated. Numerical results show that the donor binding energy depends on the impurity position, laser parameter, temperature, Al composition, and well width. The donor binding energy is decreased when the laser field and temperature are increased in the QW for any impurity position and QW parameter case. Moreover, the laser field has an obvious influence on the donor binding energy of impurity located at the vicinity of the QW center. In addition, our results also show that the donor binding energy decreases （or increases） as the well width （or AI composition x） increases in the QW.

Red fluorescent siloles with aggregation-enhanced emission characteristics

A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence （EL） performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, （MesB）2DTTPS, and （MesB）zDSTPS, showed the typical aggregation-enhanced emission （AEE） feature, while furan-containing one, （MesB）2DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of （MesB）2DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m^-2, 4.3 cd A^-1, 2.9 lm W^-1, and 1.8%, respectively.