基于CuInS2/ZnS核壳结构量子点的高光效暖白光LED

采用逐步热注射法合成了用于白光LED的CuInS₂/ZnS(CIS/ZnS)核壳结构量子点.通过调整Cu/In的比率, 在CuInS₂(CIS)量子点的基础上, 合成了发射波长在570~650 nm之间可调的CIS/ZnS量子点.与CIS量子点的低量子产率相比, 具有核壳结构的CIS/ZnS量子点的量子产率达到了78%.通过在黄光荧光粉YAG :Ce³⁺表面旋涂CIS/ZnS量子点的方式制备了暖白光LED器件.在工作电流为10 mA时, 暖白光LED的发光效率达到了244.58 lm/W.由于CIS/ZnS量子点的加入, 所制备的白光LED器件的显色指数达到86.7且发光颜色向暖色调发生了转移, 相应的色坐标为(0.340 6, 0.369 0).     

Bottom‐Up Synthesis of Carbon Quantum Dots With High Performance Photo‐ and Electroluminescence

Although carbon quantum dots (CQDs) are of great interest because of cost effectiveness and environmental compatibility with the facile tunability of their optical properties, poor photo‐ and electroluminescence (EL) of CQDs limits further implementation. Here, a novel bottom‐up synthetic route for fabricating highly crystalline CQDs suitable for high‐brightness blue light‐emitting diodes is demonstrated. The two‐step solution process is based on time‐controlled thermal carbonization of citric acid, followed by ligand exchange of the CQDs with oleylamine (OA) in solution. Carbonization allows for the nucleation and growth of crystalline CQDs, while OA treatment disperses the CQDs and stabilizes the solution, giving rise to CQDs with low structural defects and uniform sizes. The systematic study reveals the origin of the light emission of OA‐treated CQDs by photoluminescence (PL) analysis, which yields a high quantum efficiency of ≈30%. The photoluminescence‐optimized OA‐treated CQDs exhibit excellent blue EL performance with a low turn‐on voltage of ≈4 V and high brightness of 308 cd m⁻²; a negligible voltage‐dependent color shift when they are employed to an inverted light‐emitting diode.     

共振光散射法(RLS)研究外源刺激对CdSe/ZnS量子点/TiO_2纳米复合物与人血清白蛋白的相互作用的影响

近似生理条件下,采用共振光散射法研究了CdSe/ZnS量子点/TiO_2纳米复合物同人血清白蛋白的相互作用,通过分析影响二者相互作用的纳米复合物浓度、pH、NaCl浓度、反应温度、检测时间、共存离子、表面活性剂、加样顺序等外源刺激因素,结果表明:新形成的复合体系可能加强蛋白质的疏水腔,使在水溶液中形成的疏水界面趋于集中,从而导致其共振光散射强度增强;体系受pH的影响变化非常灵敏;适当的NaCl浓度可以提高体系的I_(RLS)值灵敏度;共存离子改变了体系的离子强度,从而导致体系的△I_(RLS)值的改变;反应时间为5 min时,体系I_(RLS)值基本稳定;同一种表面活性剂对于不同的体系的I_(RLS)值的作用不完全一致,带相反电荷的表面活性剂与纳米复合物有很强的静电作用;对于与HSA相互作用的多元复合体系,加样顺序的不同对体系的I_(RLS)值的影响很明显;体系的I_(RLS)值随温度的改变呈不完全单调增加的趋势。这些信息为纳米材料与生物大分子的相互作用机制提供理论支撑,有助于深入了解纳米材料的生物相容性和安全性。     

真空中线性啁啾时空高斯脉冲传输特性的分析

利用稳态相位点的方法研究了线性啁啾时空高斯脉冲传输过程中的相位特性，并在二阶近似的情况下讨论了其传输过程中的时空特性，两种方法从不同侧面得出了相同的结论，即：时空高斯脉冲在传输的过程中，在无穷远处交退化为球面波，或者在旁轴近似的情况下退化为平面波。     

Phase Modulation Characteristics Analysis of Optically-Addressed Parallel-Aligned Nematic Liquid Crystal Phase-Only Spatial Light Modulator Combined with a Liquid Crystal Display

An optically addressed parallel-aligned nematic-liquid-crystal spatial light modulator (PAL-SLM) has been studied as a dynamic phase-only light modulation device. The phase modulation characteristics of the PAL-SLM using a liquid crystal display (LCD) as an addressing mask were investigated by analyzing diffraction efficiencies resulting from binary gratings projected from the LCD. A more than 2π phase-only modulation depth was achieved. The highest first-order diffraction efficiency of approximately 38% was also obtained; this is close to the theoretical limit. The experimental results of diffraction efficiencies depending on the phase modulation depth are in good agreement with the simulation for the system operation.