Photoluminescence Detection of Biomolecules by Antibody‐Functionalized Diatom Biosilica

Diatoms are single‐celled algae that make microscale silica shells called “frustules”, which possess intricate nanoscale features imbedded within periodic two‐dimensional pore arrays. In this study, antibody‐functionalized diatom biosilica frustules serve as a microscale biosensor platform for selective and label‐free photoluminescence (PL)‐based detection of immunocomplex formation. The model antibody rabbit immunoglobulin G (IgG) is covalently attached to the frustule biosilica of the disk‐shaped, 10‐µm diatom Cyclotella sp. by silanol amination and crosslinking steps to a surface site density of 3948 ± 499 IgG molecules µm^?2. Functionalization of the diatom biosilica with the nucleophilic IgG antibody amplifies the intrinsic blue PL of diatom biosilica by a factor of six. Furthermore, immunocomplex formation with the complimentary antigen anti‐rabbit IgG further increases the peak PL intensity by at least a factor of three, whereas a non‐complimentary antigen (goat anti‐human IgG) does not. The nucleophilic immunocomplex increases the PL intensity by donating electrons to non‐radiative defect sites on the photoluminescent diatom biosilica, thereby decreasing non‐radiative electron decay and increasing radiative emission. This unique enhancement in PL emission is correlated to the antigen (goat anti‐rabbit IgG) concentration, where immunocomplex binding follows a Langmuir isotherm with binding constant of 2.8 ± 0.7 × 10^?7 M .     

2维混合介质柱光子晶体传输特性的研究

为了研究晶体结构对电磁波传输特性的影响,提出了一种空气平板层和圆形复合介质柱混合组成的新型2维混合介质柱光子晶体结构。采用时域有限差分法对其进行了数值模拟和计算,研究了改变混合介质柱的形状和结构参量对晶体透射特性的影响。结果表明,该结构可以基本保留组合前光子晶体的主带隙,并且在新的频段产生新的禁带;在混合结构中将复合介质柱换为简单介质柱没有新的禁带产生。通过改变相关参量发现,增加介质平板的宽度,这增大内嵌介质柱的半径都有利于新禁带的产生。2维混合介质柱光子晶体比单一介质柱光子晶体有更多的可调因素,这为相关光子晶体器件的设计提供了理论依据。     

介电常数对比和填充率对光子晶体中光子禁带和局域态的调节

用有限时域差分法(FDTD)和Padé近似分析了二维光子晶体的能带结构和缺陷引起的局域态.针对介电常数对比和填充率对完整光子晶体中光子禁带以及缺陷态的影响作了研究.计算了不同缺陷的光子晶体模式的振荡频率和质量因子.数值模拟的结果表明通过改变介电参数对比和填充率可以实现对光子禁带的位置、宽度、数目以及对缺陷态的调整.     

介电常数对比和填充率对光子晶体中光子禁带和局域态的调节

用有限时域差分法(FDTD)和Padé近似分析了二维光子晶体的能带结构和缺陷引起的局域态.针对介电常数对比和填充率对完整光子晶体中光子禁带以及缺陷态的影响作了研究.计算了不同缺陷的光子晶体模式的振荡频率和质量因子.数值模拟的结果表明通过改变介电参数对比和填充率可以实现对光子禁带的位置、宽度、数目以及对缺陷态的调整.     

Dendron‐Stabilized Liquid Crystalline Blue Phases with an Enlarged Controllable Range of the Photonic Band for Tunable Photonic Devices

Liquid crystalline blue phases (BPs) show excellent potential for application in tunable photonic devices because they possess the unique optical property that the selective 3D Bragg diffraction in a visible wavelength region can be continuously shifted using an electric field. A new approach to simultaneously extend the wavelength range of field‐induced Bragg diffraction shift and the temperature range of thermodynamically stable BPs is critically needed. Here, a new BP material system is shown using a dendron molecule to extend simultaneously the two BP ranges. One is the temperature range of thermodynamically stable BPs, which is expanded from 2.1 to 4.6 °C. The other is the reversible maximum shift range of Bragg wavelength on the electric field, which is extended from 85 to 109 nm. The physical mechanism of the dendron‐stabilizing effect in BPs is discussed in terms of elastic property and orientational order of liquid crystal molecules.     

Broadband Omnidirectional Diversion of Light in Hybrid Plasmonic‐Photonic Heterocrystals

Broadband, omnidirectional, and polarization‐independent diversion has been achieved of more than 90% of the light flow intensity off its incidence direction using hybrid metal–dielectric plasmonic‐photonic heterocrystals. These architectures were prepared by depositing metal film on the interface between two photonic crystals of different parameters. The magnitude of light losses was extracted from angle‐resolved measurements of transmission and reflectance spectra. Comparing these data for different stages of constructing the complex architecture, the diffraction in colloidal crystals, the excitation and radiative decay of short‐living surface plasmon polaritons in a corrugated metal film and the eigenmode mismatch at the interface between two different photonic crystals were identified as corroborating physical mechanisms behind the light diversion.     

用数值方法研究含负折射率材料的一维光子晶体的色散特性

在传统的二元一维光子晶体中,如果有一种材料在某一段频带范围内显示出负折射率特点,此光子晶体的色散特性肯定不同于传统的光子晶体.首先通过建立简单的模型推导出光波在光子晶体中传播的表达式,然后进行数值模拟和分析,并引入负折射率表达式,仿真得到这种光子晶体的色散图形.研究结果表明,该光子晶体在微波频段存在多个小的禁带,可以作为多通道滤波器.在高频带,当构成光子晶体的两种材料的厚度发生改变时,禁带的位置也会变化.     

Direct Transcription of Two‐Dimensional Colloidal Crystal Arrays into Three‐Dimensional Photonic Crystals

A simple protocol for the fabrication of three‐dimensional (3D) photonic crystals in silicon is presented. Surface structuring by nanosphere lithography is merged with a novel silicon etching method to fabricate ordered 3D architectures. The SPRIE method, sequential passivation reactive ion etching, is a one‐step processing protocol relying on sequential passivation and reactive ion etching reactions using C₄F₈ and SF₆ plasma chemistries. The diffusion of fresh reactants and etch product species inside the etched channels is found to play an important role affecting the structural uniformity of the designed structures and the etch rate drift is corrected by adjusting the reaction times. High quality photonic crystals are thus obtained by adding the third dimension to the two‐dimensional (2D) colloidal crystal assemblies through SPRIE. Careful adjustments of both mask design and lateral etch extent balance allow the implementation of even more complex functionalities including photonic crystal slabs and precise defect engineering. 3D photonic crystal lattices exhibiting optical stop‐bands in the infrared spectral region are demonstrated, proving the potential of SPRIE for fast, simple, and large‐scale fabrication of photonic structures.     

Asymmetric Tunable Photonic Bandgaps in Self‐Organized 3D Nanostructure of Polymer‐Stabilized Blue Phase I Modulated by Voltage Polarity

Electrically responsive photonic crystals represent one of the most promising intelligent materials for technological applications in optoelectronics. In this research, a polymer‐stabilized blue phase (PSBP) I film with the self‐organized 3D nanostructure is fabricated, and an electrically tunable photonic bandgap (PBG) is achieved. Interestingly, the large‐scale shift of the PBG covering the entire visible spectrum is found to be asymmetric and can be modulated by the polarity and magnitude of bias voltage. Moreover, to demonstrate the usability in optical devices, blue phase lasers are developed by doping the PSBP material with fluorescent dyes. And mirrorless lasing emission with electrically tunable wavelength is observed. This self‐assembled soft material is prospective to produce large‐scale electrically responsive photonic crystals in facile fabrication process and has enormous potential applications in intelligent optoelectronic devices, such as 3D tunable lasers, reflective full‐color displays, or photonic integrated circuits.     

Simultaneous Tenfold Brightness Enhancement and Emitted‐Light Spectral Tunability in Transparent Ambipolar Organic Light‐Emitting Transistor by Integration of High‐k Photonic Crystal

In organic light‐emitting transistors, the structural properties such as the in‐plane geometry and the lateral charge injection are the key elements that enable the monolithic integration of multiple electronic, optoelectronic, and photonic functions within the same device. Here, the realization of highly integrated multifunctional optoelectronic organic device is reported by introducing a high‐capacitance photonic crystal as a gate dielectric into a transparent single‐layer ambipolar organic light‐emitting transistor (OLET). By engineering the photonic crystal multistack and bandgap, it is showed that the integration of the photonic structure has a twofold effect on the optoelectronic performance of the device, i.e., i) to modulate the spectral profile and outcoupling of the emitted light and ii) to enhance the transistor source–drain current by a 25‐fold factor. Consequently, the photonic‐crystal‐integrated OLET shows an order of magnitude higher emitted power and brightness with respect to the corresponding polymer‐dielectric device, while presenting as‐designed electroluminescence spectral and spatial distribution. The results validate the efficacy of the proposed approach that is expected to unravel the technological potential for the realization of highly integrated optoelectronic smart systems based on organic light‐emitting transistors.     

Creation of Nanotips on ITO Electrode by Nanoparticle Deposition: An Easy Way to Enhance the Performance of Electrically Responsive Photonic Crystal and Fabricate Electrically Triggered Anticounterfeiting Tags

Electrically responsive photonic crystals (ERPC) are promising materials for electrophoretic displays, smart windows, and tunable optical devices. However, the high working voltage limits the application of most polar ERPCs because it damages color saturation, response stability, and reversibility. Herein, an easy but general method based on the modification of electrodes with nanoparticles is developed to improve ERPC's performance. The deposition of Au, Cu, or Cu₂O nanoparticles created nanotip structures on the electrode, which enhanced the charge injection and local electric field strength, lowered 43% of the working voltage, and increased the color saturation. Meanwhile, the lowered voltage inhibited the electrodeposition of colloidal particles and the electrochemical reaction, which also improved the stability and reversibility of the electrical response. Based on the region-selective modification of the electrode and the resulting asymmetric electrical response, an electrically triggered tag with a “pattern showing/hiding” effect is fabricated for anticounterfeiting purposes.     

康普顿散射对可调缺陷层等离子体光子晶体滤波的影响

应用多光子非线性康普顿(Compton)散射模型和时域有限差分方法,研究了多光子非线性Compton散射对可调缺陷层等离子体光子晶体滤波的影响。结果表明,等离子体缺陷层几何厚度不变时,随缺陷等离子体层电子密度的增大,多光子非线性Compton散射使缺陷模透射峰频率向高频方向迅速移动,缺陷模中心频率向高频方向近乎线性地迅速移动。等离子体缺陷层厚度增大时,多光子非线性Compton散射使缺陷模的中心频率向低频方向移动;厚度增加到一定值时,在带隙上边沿处产生一个高于Compton散射前频率的缺陷模频率。     

Photoluminescence and raman scattering characterization of silicon-doped In0.52Al0.48As grown on InP (100) substrates by molecular beam epitaxy

Growth of In_0.52Al_0.48As epilayers on InP (100) substrates by molecular beam epitaxy at different silicon doping levels is carried out. The doped samples show an inverted S-shaped dependence of the PL peak energy variation with the temperature which weakens at high doping levels due to a possible reduction in the donor binding energy. There is a reduction in both the AlAs-like and InAs-like longitudinal-optic (LO) phonon frequencies and a broadening of the LO phonon line shape as the doping level is increased. The PL intensity also showed in increasing degrees at higher doping levels, a temperature dependence which is characteristic of disordered and amorphous materials.     

In Vivo Examination of an Injectable Hydrogel System Crosslinked by Peptide–Oligosaccharide Interaction in Immunocompetent Nude Mice

Hydrogels can serve as matrices to mimic natural tissue function and be used for wide‐ranging applications such as tissue regeneration and drug delivery. Injectable hydrogels are particularly favorable because their uses are minimally invasive. However, creating moldable substance for injection often results in compromised function and stability. This study reports an injectable hydrogel system crosslinked by peptide–oligosaccharide noncovalent interaction. The dynamic network shows fast self‐healing, a property essential for injectability. Injected hydrogels in immunocompetent mice and release of encapsulated compound are monitored up to 9 months by magnetic resonance imaging (MRI) and optical imaging. This surprisingly stable hydrogel does not cause adverse inflammatory response, as analyzed by measuring cytokine levels, immunohistochemistry, and MRI. Hydrogel degradation is associated with invasion of macrophages and vascular formation. The facile synthesis, high biocompatibility, and stability of this injectable hydrogel can lead to various experimental and clinical applications in regenerative medicine and drug delivery.