Simple near‐infrared photodetector based on charge transfer complexes formed in molybdenum oxide doped N,N′‐di(naphthalene‐1‐yl)‐N,N′‐diphenyl‐benzidine

We have demonstrated a simple near‐infrared (NIR) photodetector (PD) based on charge transfer complex (CTC) formed in molybdenum trioxide (MoO₃) doped N,N′‐di(naphthalene‐1‐yl)‐N,N′‐diphenyl‐benzidine (NPB), which shows a photocurrent of about 0.35 A/cm² at –3 V under 980 nm illumination. The existence of CTC formation promotes photocurrent generation which is investigated by comparison with MoO₃ doped 2‐methyl‐9,10‐di(2‐naphthyl)anthracene (MADN) film which has no CTC absorption. It can be evolved that this kind of simple‐structure photodetector has potential application in the near‐infrared (NIR) detection area. It is shown in this Letter that although both MoO₃ and NPB have larger energy gaps of about 3 eV and weak absorption in the NIR region, the charge transfer complexes formed by mixing the two materials show an extra absorption band and good photoelectric response in the NIR region.

     

Palladium-catalyzed intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides

Give me a ring? An efficient approach has been developed for the intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides catalyzed by palladium (see scheme). From a synthetic viewpoint, this method is highly attractive because the catalyst loading is low, the optimized reaction conditions are mild, and the substrate scope is broad.     

Tunability of UV electroluminescence for n-ZnO:Al/n −-ZnO/i-MgO/n-GaN heterostructured light-emitting diodes

n-ZnO:Al/n ^?-ZnO/i-MgO/n-GaN heterostructured diodes have been fabricated by radio frequency magnetron sputtering. The electroluminescence (EL) of the n-ZnO:Al/n ^?-ZnO/i-MgO/n-GaN diodes has been investigated. All EL spectra are dominated by ultraviolet (UV) emission peaked at around 368 nm. However, EL performances of the devices can be tuned through controlling the electrical parameters of ZnO:Al films. With the variation of the ZnO:Al films, EL spectra could evolve into random lasing action from conventional EL. The electrical parameters of the corresponding ZnO:Al films were researched, and the related UV emission mechanism is discussed in terms of the energy-band theory of the heterojunctions.     

一类泛函微分方程半正问题的正周期解

运用Krasnosel’skii不动点理论研究了一类含参泛函微分方程半正问题正周期解的存在性．获得了当参数充分小时正周期解的存在性结果以及半正问题正周期解存在的充分条件．丰富了一阶泛函微分方程解的存在性理论．     

厄尔尼诺/拉尼娜-南方涛动非线性扰动模型孤子的渐近解法

研究了一类厄尔尼诺/拉尼娜-南方涛动(ENSO)随机扰动模型. 首先, 利用特殊的待定系数方法得到了无扰动ENSO模型下的孤子精确解. 然后利用渐近理论和方法构造了随机扰动ENSO模型的近似解, 并举例说明得到的渐近解具有较好的精度.     

一类扰动发展方程近似解

采用了一个简单而有效的技巧, 研究了一类扰动发展方程. 首先引入求解一个相应典型方程的行波孤波解. 然后利用渐近方法得到了原扰动发展方程的近似解. 利用泛函分析的不动点定理, 指出了近似解级数的收敛性, 并讨论了近似解的精度.     

高功率激光系统nm宽带激光脉冲传输特性

对高功率激光系统采用宽带激光消除菲涅耳衍射问题进行了研究,指出只有数百nm的宽带啁啾光脉冲才对近场衍射有一定的平滑作用,数nm的宽带啁啾光脉冲对近场衍射几乎没有平滑作用;同时,还对宽带啁啾光的B积分表征方式和最快增长频率问题进行了研究,并与原型装置上开展的窄带脉冲、宽带啁啾堆积脉冲的非线性实验结果进行了对比研究,指出以最大B积分或加权B积分反映非线性自聚焦更为准确。研究还表明,在数nm,ns情况下最快增长频率与窄带激光脉冲的差别不大。     

Asymptotic solution of nonlinear nonlocal singularly perturbed reaction diffusion problems with two parameters

A class of differential-difference reaction diffusion equations initial boundary problem with a small time delay is considered. Under suitable conditions and by using method of the stretched variable, the formal asymptotic solution is constructed. And then, by using the theory of differential inequalities the uniformly validity of solution is proved.     

Cavity-dumped electro-optical Q-switched Nd:GdVO4 laser with high repetition rate

We reported a cavity-dumped operation of electro-optical Q-switched Nd:GdVO₄ laser at high repetition rates for the first time. A constant 5.5 ns pulse duration was realized. The maximum average output power was 5.1 W at the highest repetition rate of 50 kHz, corresponding to a peak power of 18.5 kW.     

Synthesis and characterization of highly conductive Sn–Ag bimetallic nanoparticles for printed electronics

To synthesize low-cost, highly conductive metal nanoparticles for inkjet printing materials, we synthesized Sn–Ag bimetallic nanoparticles using a polyol process with poly(vinyl pyrrolidone). Because a surface oxidation layer forms on Sn nanoparticles, various compositions of Sn–xAg [x = 0, 20, 40, 60, 80, 100 (wt%)] nanoparticles were synthesized and characterized for the purpose of removing the β-Sn phase. The results of XPS, TEM, and XRD analyses confirm that the formation of a bimetallic phase, such as Ag₄Sn or Ag₃Sn, hinders the β-Sn phase and, consequently, leads to the removal of the surface oxidation layer. To measure the sheet resistance of various compositions of Sn–Ag nanoparticles, we made the ink that contains Sn–Ag by dispersing 10 wt% of Sn–Ag nanoparticles in methanol. The sheet resistance is decreased by the conductive Sn–Ag phases, such as the fcc, Ag₄Sn, and Ag₃Sn phases, but sharply increased by the low-conductive Sn nanoparticles and the surface oxidation layer on the Sn nanoparticles. The sheet resistance results confirm that 80Ag20Sn and 60Ag40Sn bimetallic nanoparticles are suitable candidates for inkjet printing materials.