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SiO₂ glass powder and a certain mass proportion of YAG:Ce³⁺phosphor powder were taken to prepare SiO₂-YAG:Ce³⁺ PG with melting method, and then the samples were prepared into 0.2 mm thickness for XRD phase, structure of optical micrographs and SEM, and PL spectrum test analysis. The results show that the phase of phosphor is retained in PG and the phosphor particles are uniformly distributed in the glass matrix. Consistent excitation and response relationship of PG and phosphor is observed that the excitation wavelength is about 465 nm and the emission wavelength is about 535 nm. The structure characteristics of phosphor are retained in PG except the glass phase. The blue LED chips with different wavelengths were packaged with the PG samples. The test results indicate that the luminous efficiency can reach at 234.81 lm/W, and the color temperature and CRI monotonically decrease with the increasing of phosphor content in PG, all of which are at a high level. Under different wavelength excitation, x and y in the chromaticity coordinates present roughly same linear rate of change when the mass fraction of phosphor in PG increases from 6% to 15%. In addition, the temperature of PG rose relative slowly and dropped sharply when the PG sample was excited by 450 nm laser, indicating a nice property of heat resistance. The experiment results show that the superior optical properties and heat resistance can be obtained by PG packaged LED, and excellent white light output can be formed.

A series of Ba₂SiO₄:Gd³⁺,Tb³⁺green phosphors were synthesized by solid state reaction. The influence of the factors such as the amount of ion doping on the luminescence properties was investigated. Their structure and luminescence properties were characterized by X-ray diffraction (XRD) analysis, fluorescence spectrometry (FL), and decay curves. The spectroscopic properties of Ba₂SiO₄:Gd³⁺,Tb³⁺ under the excitation of the characteristic absorption wavelength of Gd³⁺ and Tb³⁺ were investigated. The emission of Tb³⁺ was observed under 275 nm(Gd³⁺: ⁸S_7/2→⁶I_J) excitation. By comparing Gd³⁺: ⁶P_7/2 energy decay curve with different Tb³⁺ doping amount, it is found that the level of fluorescence continuously shorten the service life with the increasing of Tb³⁺ concentration, indicating the occurrence of energy transfer from Gd³⁺ to Tb³⁺ with the mode of nonradiative resonance transfer. Under the excitation of 244 nm (Tb³⁺: 4f⁸→4f⁷5d¹), the emission intensity of ⁵D₃level decreases, but the ⁵D₄ level increases with the doping of Gd³⁺. The emission intensity at 544 nm (⁵D₄→⁷F₅) increases 59%~128% with the doping of Gd³⁺. Combining with the fluorescence decay curves, it is found that the doping of Gd³⁺ can promote the cross relaxation of ⁵D₃→⁵D₄ and ⁷F₆→⁷F₀ in Tb³⁺.

Ce:YAG (cerium doped yttrium aluminum garnet) transparent ceramics were synthesized by solid state reaction method with high pure Al₂O₃, Y₂O₃ and CeO₂ as raw materials. The influence of the sintering temperature and doping concentrations on the ceramic sample's performance was studied. The results show that the transmission of the ceramics increases with the sintering temperature increasing. The relatively higher transmission of 81.7% can be obtained for 0.5%Ce:YAG ceramics sintered at 1 750 ℃. The exciting band and the emitting band of Ce:YAG ceramics lie in 350 nm and 530 nm, which show that Ce:YAG ceramics might be promising materials in the white-LED filed.

Novel carbon dots were successfully synthesized by hydrothermal reaction with citric acid as carbon source, and 4-amino-2,2,6,6-tetramethylpiperidine was used to react with the oxygen-containing groups on carbon dots surface. This method would optimize the properties of carbon dots. The modified carbon dots are better than the unmodified carbon dots on the characteristics of ultraviolet absorption and blue fluorescence-emission. The modified carbon dots exist in average particle size of 3.16 nm, and have high fluorescence quantum yield of 21.2% besides good water solubility and light color. The results show that the novel carbon dots can be used as light stabilizer in papermaking with high yield pulp and improved initial brightness of paper by 3ISO%-4ISO%. With the introducing of the radical scavenger groups, the novel carbon dots can effectively improve the light resistance of paper by capturing free radicals formed under lights.

A facile preparation of orange fluorescent porous silicon (PS) was reported using a simple chemical etching method at 45 ℃. The prepared PS samples were characterized by scanning electron microscope(SEM), Fourier translation infrared spectrum(FT-IR) and specific surface area(BET). The results show that PS samples emit strong orange fluorescence possessing excellent photostability. Moreover, the fluorescence of PS can be effectively quenched by Ag⁺ at room temperature.The fluorescence of PS shows a good linear relationship with the concentration of Ag⁺in the range of 4.5×10^-8-6.6×10^-7 mol/L, the detection limit is 2.2×10^-8 mol/L, and the correlation coefficient is 0.991 4. The mechanism of Ag⁺-sensing in this method was further explained. Furthermore, the fluorescent Ag⁺ sensor was applied to Ag⁺ detection in environmental water samples, and satisfactory results were obtained.

Hexadecyloxylallene was prepared by the substitution reaction of propargyl alcohol with bromohexadecane and the followed rearrangement reaction. Poly(3-hexylthiophene)-b-poly(hexadecyloxylallene) copolymers was then synthesized in one pot via sequential addition of monomers of 3-hexylthiophene and hexadecyloxylallene by using Ni(dppp)Cl₂ as a single catalyst. The products were confirmed by ¹H NMR and size-exclusion chromatography (SEC). The thermal, optical and electrical properties of the obtained block copolymer were investigated. The analysis of P3HT-b-PHA in the solid state using differential scanning calorimetry (DSC) and thermogravimetric analysis(TGA) revealed that the material could undergo microphase separation, as two glass transition temperatures (T_g) and two part of the decomposition process assignable to both P3HT and PHA phases were observed. The thin-film transistors (TFT) with bottom-gate top-contact configuration were fabricated to characterize the electrical properties of the obtained block copolymer. The TFT devices were subsequently annealed at different temperatures (room temperature, 100, 150, and 200 ℃) in a glovebox under nitrogen condition. The field-effect mobility shows an increasing trend when the annealing temperature increases. Thermal annealing is performed as an effective method to optimize the device performance because it can improve the crystallinity of the thin film. Meanwhile, thermal annealing can significantly lower the effect of the residual solvent on the carrier transport, resulting in efficient charge carrier transport. When the annealing temperature is 200 ℃, polymer-based OTFTs devices yield an average field-effect mobility of 7.03×10^-4 cm²·V^-1·s^-1, and a maximum field-effect mobility of 1.3×10^-3 cm²·V^-1·s^-1. The transfer curve shows that the threshold voltage is 5.44 V.

In order to optimize InGaN solar cell (SC) structures and effectively guide the preparation, the properties of n-i-p InGaN SC structures with graded In composition were investigated. Through APSYS simulation software, the performances of p-i-n and n-i-p SC structures with graded In composition were compared. It is found that n-i-p structures don't have obvious advantage in the device performance over p-i-n ones when In composition of i-InGaN layer is low, which yet presents better performance with higher In composition. When In composition is 0.62, the SC conversion efficiency reaches 8.48%. The further analysis indicates that the polarization electric field in InGaN layer has the same directions with the built-in one in the depletion region for the case of n-i-p SC structures, which is very beneficial for carrier transport. The n-i-p SC structures with graded In composition are proven to be beneficial for high performance InGaN SCs.

In order to realize the high efficiency OLEDs by solution process, a cross-linkable host material, VB-CzTAZ containing carbazole and 1,2,4-triazole units was designed and synthesized. It is found that VB-CzTAZ with styryl groups can be thermally cross-linked by curing at 190 ℃ without any polymerization initiator. Besides the excellent thermal stability (T_d:323 ℃) and good surface morphology, the thermally cross-linked film of VB-CzTAZ also shows excellent solvent resistances as rinsing with different solvent. For the phosphorescent OLEDs (PhOLED) incorporating VB-CzTAZ as host, the turn-on voltage is 5.1 V, the maximum luminance is 2 404 cd/m², and the maximum current efficiency is 4.3 cd/A, respectively. It indicates that the cross-linkable host material has potential to be used for the solution-processed multilayer PhOLED.

In order to study the GaInAs/GaAsP multiple quantum well solar cells (MQW-SC) with different periods, double-junction solar cell samples with different periods quantum well (QW) and reference sample without QW were grown by metalorganic chemical vapor deposition (MOCVD). The crystal quality of the samples was judged by high resolution X-ray diffraction (HXRD) and high resolution transmission electron microscopy (TEM). I-V curves and external quantum efficiency (EQE) of samples were measured under AM0 (1×) spectra. Relative to the non-QW sample, the absorption spectra of QW samples extend from 890 nm to 954 nm, the highest external quantum efficiency of the extending spectra achieves 75.18%, the conversion efficiency increases by 2.77%. With the increased periods of quantum wells structure, the response of the extending spectra and the longer wavelengths (700-890 nm) in the conventional spectra increase, while in the shorter wavelengths (300-700 nm) the response has a fall. Eventually, the short circuit current and the efficiency of the cells are improved and finally tend to be steady.

In order to meet the short-wavelength applications of the superluminescent diodes, a bent-waveguide superluminescent diode was fabricated by using InAlGaAs/AlGaAs quantum-dot active region and dry etching process. The peak output power up to 29 mW with the wavelength centered at 880 nm and the full-width at half-maximum of 20.3 nm were obtained. Also the influences of wet etching and dry etching on the device properties were compared. At 1.6 A pulsed current injection, the peak output power of the device fabricated by wet etching is only 7 mW. Compared with wet etching, dry etching can precisely control the shape and parameters of the waveguide, leading to smaller waveguide loss and higher output power.

The experiments of dose rate on charge coupled devices(CCDs) were carried out to investigate the relationship between the dose rate and the electrical parameters of the device, and the degradation mechanism was analyzed. With the accumulation of the dose, the dark signal (DS)and dark non-uniformly signal(DNS) increase significantly, and the both charge transfer efficiency (CTE)and saturation output voltage(SOV) tend to decrease slowly. The whole dark pixel value uplifts and the non-uniform between pixels becomes obviously. The dark signal of the CCD is negatively correlated with the dose rate, and the device presents the potential of the-low-dose-rate-damage enhancement effect. It is considered that the dose rate effect is caused by the competition between the interface states and oxide traps, and the mechanism is explained by the electron-hole pair recombination model and the damage model in the annealing process.

This essay has reported normally-off operation of an AlGaN/GaN recessed MOS-gate high electron mobility transistor(MOS-gate HEMT) fabricated by the inductively coupled plasma(ICP) recessed technique. A 40-nm Al₂O₃ film was deposited by the atomic layer deposition(ALD) as the gate dielectric. The normally-off recessed MOS-gate AlGaN/GaN HEMT with a gate length of 2 μm and a gate width of 0.9 mm exhibits a high threshold voltage of+4.6 V, a specific on-resistance of 4 mΩ·cm² and a drain current density of 108 mA/mm (at a positive gate bias of 10 V). When the gate bias (V_gs) is 0 V, the breakdown voltage(BV) of 450 V has been achieved at a drain leakage current of 0.025 mA/mm for the recessed MOS-gate HEMT with a gate-drain distance of 10 μm. The on/off drain-current ratio (I_on/I_off) is 5×10⁸ for the recessed MOS-gate HEMT. Under a negative gate bias of -20 V, the gate leakage current of the recessed MOS-gate HEMT was 0.65 nA.

Organic field-effect transistors(OFETs) based on titanyl-phthalocyanine (TiOPc) were fabricated, and the temperature of ITO substrate(T_sub) was optimized. The results show that the carrier mobility(μ), photosensitivity(P), and photoresponsivity(R) increase firstly, and then decrease with the increasing of T_sub. When T_sub=140 ℃, OFETs exhibit a maximum carrier mobility of 1.35×10^-2 cm²·V^-1·s^-1, a maximum photosensitivity of 250, and a maximum photoresponsivity of 1.51 mA/W under the illumination by a laser diode with a wavelength of 808 nm and power density of 190 mW·cm^-2.

A novel white electrophosphorescent organic light emitting diodes (PHOLEDs) with a structure of ITO/NPB/TCTA/FIrpic:TCTA/Ir(MDQ)2(acac):TmPyPB/FIrpic:TmPyPB/TmPyPB/LiF/Al was demonstrated. The red emitting layer (Ir(MDQ)2(acac):TmPyPB) with different thickness and doping concentration was inserted between the double blue-emitting layers (D-BEML) to adjust the distribution of carriers and excitons. The luminescent properties of the devices were studied. The results showed that the optimum performance of OLED was achieved when the thickness of Ir(MDQ)2(acac):TmPyPB red emitting layer is 2 nm, and the doping mass fraction is 5%. Combining the D-BEML and the red emitting layer, WOLEDs with peak efficiencies of 11.50 cd/A and CIE coordinates of (0.333, 0.333) can be obtained.

In order to acquire penetrability of terahertz (THz) for common fabric, transmission model of fabric at THz frequency was built and described, which was based on physical structure of it and various influencing factors on THz transmission in atmosphere, to calculate the transmittance of fabric at THz on different relative humidity (RH) levels. Then, transmission experiment about cotton sample on different RHs was conducted by using terahertz time-domain spectroscopy to obtain the transmittance of sample at 0.1－2 THz. The effectiveness and veracity of the model were verified by comparing the results of theoretical calculation and experiment. And transmission characteristic of THz for cotton fabric at different environmental conditions was obtained. In addition, transmission experiment of THz for multilayers fabric was conducted on 30%RH. The results show that the fabrics, which are opaque in visible region, are almost transparent in terahertz region. But the transmission characteristic is partly influenced by environmental RH. Therefore, this research is of significance in rapid detection and identification of concealed danger in cloth.

A new ternary complex of [Cu(phen)(SA)₂]·H₂O (phen=1,10-phenanthroline, SA=salicylic acid) was synthesized and the electrochemical behavior was studied. In addition, with hsDNA as the research target, the interaction between the complex and hsDNA was investigated by UV absorption spectroscopy, CV method, differential pulse voltammetry (DPV), and DNA viscosity titration experiment. The experiment results indicate that —COOH of SA and N of phen are liganded with Cu²⁺. Cyclic voltammetric shows that the complex has one pairs of redox peaks at 0.489 V/0.050 V, and the reaction of Cu²⁺on the electrode is controlled by diffusion. With the addition of hsDNA, the UV absorption peaks of complex red-shift and the intensity is weakened, the peak current decreases significantly and the potential moves positively, and the relative viscosity of hsDNA increases. It's concluded that [Cu(phen)(SA)₂]·H₂O and hsDNA bind by the mode of intercalation, the combining ratio and the binding constant are 1:1 and 1.55×10⁴ L·mol^-1, respectively.

In order to solve the problems including the complication of the empirical manual optimization and the difficulty of achieving an ideal effect in edge-lit LGP, an automatic optimization design method based on fuzzy optimization theory is proposed. The shape of the dot is considered to be conical, and the relationship between the semi-vertical angle and the position of the dot is analyzed. It is found that the correlation degree between the light distribution in target face and the dot distribution under it can be increased, and the semi-vertical angle is merely determined by the position of the dot. The radius of the dot is adopted as the main optimization parameter. A membership function is used to fuzz the dot structure, and a self-defined evaluation function is used in the defuzzification to realize uniform illumination. Furthermore, the data exchange, ray tracing and fuzzy optimization are then automatically performed by TracePro via dynamic data exchange (DDE) between Matlab and TracePro. It is demonstrated that the uniformity and the light utilization efficiency after fuzzy optimization can reach 92.17% and 70.37%, respectively. The advantage of our scheme is that the whole fuzzy optimization is purely automatic without any manual adjustment.

Electro-optic modulators with high linearity are core devices of microwave photonic link. The modulation mechanism of the silicon optical modulator is based on the carrier dispersion effect which is nonlinear and its nonlinearity is highly related to the structure of PN junction. In this paper, the second-order spurious-free dynamic range (SFDR₂) is introduced to characterize the second harmonic distortion (SHD) of modulators. The SHD of silicon optical Mach-Zehnder modulator (MZM) based on two most widely used doping patterns, i.e., the lateral and the interdigitated PN junctions are compared with each other. The experimental results show that the lateral PN junction and interdigitated PN junction based MZMs have SFDR₂ of 85.11 dB·Hz^1/2 and 78.44 dB·Hz^1/2, respectively. The lateral PN junction based MZM has a better linearity.