量子点增强硅基探测成像器件的研究进展

硅基探测成像器件具有可靠性高、易集成和成本低等优点,是目前应用最广泛的探测成像器件。随着人工智能和无人驾驶等技术的日益发展,对探测成像器件提出了更高的要求,而硅基探测成像器件性能的提升成为重要的研究方向。量子点具有吸收系数大、光谱可调、发光效率高和易集成等优点,是一类优异的光谱转换和光调制材料。利用量子点材料可调制的光学特性,可以对硅基探测成像器件的功能进行拓展,从而实现紫外响应增强、红外响应拓展、紫外偏振探测和多光谱成像等功能。经过多年的研究,这一领域已经取得了一定的进展,部分技术展现出较好的应用前景。本文介绍了量子点增强硅基探测器在紫外探测、红外成像、偏振探测和多光谱成像方面的研究进展,希望能够引起国内学术界和工业界的关注和重视。

硒化铅核壳量子点的合成与应用研究进展

硒化铅(PbSe)量子点具有宽红外光谱调控范围、高荧光量子产率和可溶液加工等特点,成为一类重要的红外材料体系。与广泛研究的PbS量子点相比,PbSe量子点在空气中容易氧化,从而严重破坏其光电特性,制约了其应用的发展。壳层的包覆是有效提升PbSe量子点光学特性和化学稳定性的策略之一,是推动PbSe量子点应用发展的材料研究方向。本文综述了PbSe核壳量子点的合成及其在光电探测、太阳能电池、激光器和光催化等领域的应用研究进展,希望能够为国内研究者开展相关研究提供参考。

金属离子掺杂提高全无机钙钛矿纳米晶发光性质的研究进展

金属卤化物钙钛矿纳米晶由于其卓越的光电子性能,在发光二极管、激光器、X射线成像、太阳能电池及光电探测等领域中受到了极大的关注.与有机-无机杂化钙钛矿纳米晶相比,全无机钙钛矿CsPbX3(X=Cl,Br,I)纳米晶具有更优异的光电性能和更高的稳定性.为进一步提高CsPbX3纳米晶的光致发光量子效率和稳定性,有研究已经着手调控纳米晶的微观结构,减少作为非辐射复合中心的缺陷.近年来,在金属离子掺杂CsPbX3纳米晶过程中,发现不同种类和不同掺杂浓度的金属离子对其电子能带结构和光致发光性能有着巨大的影响,基于金属离子掺杂取得了光致发光量子效率接近100%的CsPbX3纳米晶.本文综述了近年来在CsPbCl3,CsPbBr3,CsPbI3和Mn^2+掺杂CsPbX3(Mn^2+:CsPbX3)四种体系中通过金属离子掺杂提高全无机钙钛矿纳米晶光学性能的研究进展及其性能提升的物理机制.此外,提出了下一步还需要深入研究的一些问题和策略,通过这些问题的深入研究,希望能促使全无机钙钛矿纳米晶在各种光电器件中得到更广泛的应用.

Core-Shell Structure and Photoluminescence of CdS Quantum Dots

A double-potential-well model is proposed to describe the core-shell thickness-dependent photoluminescence peaks and energy relaxations in semiconductor quantum dots (QDs). The surface effect plays an important role in the formation of new states-polaronic states around the surface of QDs. The polaronic states formed emit light due to the strong interaction between the core state (confined state) and the surface state with an enhanced participation of the size effect.

磁耦合Mn^(2+)-Mn^(2+)离子对发光行为研究进展

过渡金属Mn^(2+)掺杂的半导体/绝缘体作为发光材料在照明、显示等领域具有重要应用。Mn^(2+)离子具有5个未成对的d电子,掺杂在发光材料中通常具有高自旋态,其容易与近邻的Mn^(2+)离子发生交换或超交换作用即磁相互作用。此类相互作用可在分子尺度下对电子自旋产生很强的束缚能力,使得磁耦合Mn^(2+)-Mn^(2+)离子对的发光行为不同于孤立Mn^(2+)离子的发光行为,如荧光寿命变短、异常的发射波长红移/蓝移、多峰发射以及异常的磁光现象等。但由于受到浓度猝灭、缺陷、声子耦合、能量传递、与半导体激子的sp-d交换作用等多因素的影响以及测试技术的限制,对Mn^(2+)-Mn^(2+)离子间磁相互作用的确认及其对发光行为的影响仍存在较多争议。随着研究的不断深入和一些新的表征手段如光磁测量技术的引入,上述问题可以得到部分解决。本文首先简要介绍过渡金属离子磁相互作用类型及其理论基础;然后综述Mn^(2+)-Mn^(2+)离子间磁相互作用对其吸收光谱、发射光谱、荧光寿命和磁光效应的影响,并着重比较探讨了能证明Mn^(2+)-Mn^(2+)磁相互作用的存在及其作用类型的不同技术手段;最后进行总结并对此类材料在LED器件等领域的潜在应用进行了展望。

Anomalous Emission And Carrier Effect of Fresh Porous Silicon

The emission and Fourier transformation infrared spectra of freshly prepared porous silicon(PS) and the silicon wafer were examined. Increasing temperature generally led to a decrease in the emission intensities of the PS samples, however, the freshly prepared sample showed an unusually large and sudden increase in its emission intensity at the specific temperature at which the hydrogen ion conductivity in the silicon wafer increased. The O-H vibrations of the silicon wafer also showed a sudden decrease at the same temperature. These results are consistent with the assumption that the luminescence of fresh PS comes from the carrier bound exciton in its confined nanostructure.

Nonresonant Optical Nonlinearities of Surface Chemically Modified ZnO Composite Nanoparticles

With surface chemical modification,we have obtained core-shell structure ZnO nanoparticles.The nonresonant third-order nonlinear optical refraction of this new composite material was found to be-3.8×10^(-10) esu by Z-scan measurements with a femtosecond pulsed laser.The ultrafast nonlinear response time~250 fs measured by time-resolved pump-probe techniques suggests that the nonlinearity of this new material originates mainly from a rapid electronic polarization process or virtual process such as the optical Stark effect.

Large Non-resonant Nonlinear Optical Susceptibility of Cu_(2)O Microcrystallites

We report the measured results of non-resonant nonlinearity by degenerate four-wave mixing for Cu2O nanopartides having central diameter of 9 nm.The value of x^(3) obtained in a 10ns pulse experiment is 8.48×1O^(-10) esu,and the nonlinear response time of the sample is estimated to be in the order of nanosecond.