One-dimensional molecular co-crystal alloys capable of full-color emission for low-loss optical waveguide and optical logic gate

The luminescence color of molecule-based photoactive materials is the key to the applications in lighting and optical communication.Realizing continuous regulation of emission color in molecular systems is highly desirable but still remains a challenge due to the individual emission band of purely organic molecules.Herein,a novel alloy strategy based on molecular co-crystals is reported.By adjusting the molar ratio of pyrene(Py)and fluorathene(Flu),three types of molecular co-crystal alloys(MCAs)assemblies are prepared involving Py-Flu-OFN-x%,Py-Flu-TFP-x%,Py-Flu-TCNB-x%.Multiple energy level structure and Förster resonance energy transfer(FRET)process endow materials with tunable full-spectra emission color in visible region.Impressively,these MCAs and co-crystals can be successfully applied to low optical loss waveguide and optical logic gate by virtue of all-color luminescence from blue across green to red,together with smooth surface of onedimensional microrods,which show promising applications as continuous light emitters for advance photonics applications.

Bi_(2)O_(2)Se nanoplates for broadband photodetector and full-color imaging applications

Broadband light detection and sensing are widely applied in modern technology.As a promising candidate for next-generation two-dimensional(2D)optoelectronic material,bismuth oxyselenide(Bi_(2)O_(2)Se)nanoplates exhibit many prospects in the application of visible light detection due to their peculiar properties.In this work,we report the photodetection performance of single-crystal 2D Bi_(2)O_(2)Se nanoplates grown on SiO_(2)based on a ternary-alloy growth model by utilizing chemical vapor deposition(CVD).The Bi_(2)O_(2)Se nanoplates were found to have an even and uniform square shape with side lengths up to 15μm and an approximate thickness of 15 nm.A visible-light photodetector was fabricated based on a CVD-grown Bi_(2)O_(2)Se nanoplate,and characterized by a set of illumination experiments using a 400 nm laser at temperatures ranging from 77 to 370 K.The device exhibited superior performance at the temperature of 77 K,with a responsivity of 523 A/W,a specific detectivity of 1.37×10^(11)Jones,a response time of 0.2175 ms,an external quantum efficiency of 162,119.44%,resulting in high-quality and fullcolor imaging in the visible spectrum.These results indicate that the single-crystalline Bi_(2)O_(2)Se nanoplates have excellent potential in broadband photodetection and non-cryogenic imaging.

Memorable full-color circularly polarized luminescence from chiral co-assembled polymer films enabled by multipath transfer

The modulation of circularly polarized luminescence(CPL)is of importance for display and asymmetric chemical synthesis.However,the underlying mechanism of CPL transfer remains rarely studied.Herein,we rationally design a multipath transfer system including multistep chirality transfer(MCT)and sequential fluorescence resonance energy transfer(SFRET),and we are the first to fabricate memorable full-color CPL-active films with a high dissymmetry factor(~10^(-2)).Specifically,(P/M)-helical nanofibers are constructed by co-assembly between an achiral polymer,poly(9,9-di-n-octylfluorene)(PF8),and easy-to-remove R/S-limonene.When matching achiral emitters are added,the PF8 mediates MCT and simultaneously triggers the SFRET process.Furthermore,full-color CPL memory is realized after removing the chiral source.Molecular simulation and structure analysis indicate that the robust helical superstructure of PF8 provides chiral sites to accommodate emitters,which is essential for CPL transfer and memory.This work provides a novel strategy for constructing CPL-active materials in an aggregated state and insights into CPL transfer and memory.

Recent Advances in Patterning Strategies for Full‑Color Perovskite Light‑Emitting Diodes

Metal halide perovskites have emerged as promising light-emitting materials for next-generation displays owing to their remarkable material characteristics including broad color tunability,pure color emission with remarkably narrow bandwidths,high quantum yield,and solution processability.Despite recent advances have pushed the luminance efficiency of monochromic perovskite light-emitting diodes(PeLEDs)to their theoretical limits,their current fabrication using the spincoating process poses limitations for fabrication of full-color displays.To integrate PeLEDs into full-color display panels,it is crucial to pattern red–green–blue(RGB)perovskite pixels,while mitigating issues such as cross-contamination and reductions in luminous efficiency.Herein,we present state-of-the-art patterning technologies for the development of full-color PeLEDs.First,we highlight recent advances in the development of efficient PeLEDs.Second,we discuss various patterning techniques of MPHs(i.e.,photolithography,inkjet printing,electron beam lithography and laserassisted lithography,electrohydrodynamic jet printing,thermal evaporation,and transfer printing)for fabrication of RGB pixelated displays.These patterning techniques can be classified into two distinct approaches:in situ crystallization patterning using perovskite precursors and patterning of colloidal perovskite nanocrystals.This review highlights advancements and limitations in patterning techniques for PeLEDs,paving the way for integrating PeLEDs into full-color panels.

基于多维度特征融合的敦煌壁画修复图像质量评价方法

针对使用传统评价指标、依托单一特征来反映修复后古代壁画图像质量的局限性,同时为增加古代壁画修复图像质量评价方法的多元性与丰富性,本文结合敦煌壁画图像颜色特征和纹理特征,提出一种基于多维度特征融合的全参考敦煌壁画修复图像质量评价方法。首先,分别计算原完好壁画图像与修复后壁画图像的颜色熵差、归一化中心距差、颜色直方图的卡方距离、颜色标准差之差值、图像能量差、相关性差、对比度差以及同质性差值;其次,利用主成分分析法采用8个特征属性建模得到质量评价模型,模型的输出值即为修复后图像的质量得分。在有效性验证实验中,该方法的得分获得与其他传统的客观评价方法一致的结果,二者具有较强的相关性。该评价指标综合分析敦煌壁画图像的色彩分布以及纹理的细节保留和模式的重现,实现了一种全方位、多层次的图像修复质量评价方法。

反向混合并联Micro LED/OLED显示器件的驱动IC控制

提出一种集成蓝光微发光二极管(Micro LED)和红绿光有机发光二极管(OLED),具有特殊子像素排列的新型无源驱动全彩显示器件.该器件无需巨量转移就可实现全彩化显示,且较传统全彩OLED及Micro LED,器件效率更高,寿命更长.另外,将蓝色与绿色子像素反向并联,可以减少电极走线,提高器件像素密度.针对该器件的特殊结构,设计一套全新的驱动方案,具体以现场可编程逻辑门阵列FPGA作为主控制器,利用驱动芯片提供稳定的电流点亮LED,实现器件的全彩显示.通过仿真测试进一步验证了该器件良好工作的可行性.

Full-color monolithic hybrid quantum dot nanoring micro light-emitting diodes with improved efficiency using atomic layer deposition and nonradiative resonant energy transfer

Full-color displays based on micro light-emitting diodes(μLEDs) can be fabricated on monolithic epitaxial wafers. Nanoring(NR) structures were fabricated on a green LED epitaxial wafer; the color of NR-μLEDs was tuned from green to blue through strain relaxation. An Al_2O_3 layer was deposited on the sidewall of NR-μLEDs,which improved the photoluminescence intensity by 143.7%. Coupling with the exposed multiple quantum wells through nonradiative resonant energy transfer, red quantum dots were printed to NR-μLEDs for a full-color display. To further improve the color purity of the red light, a distributed Bragg reflector is developed to reuse the excitation light.

Optical cross-talk reduction in a quantumdot-based full-color micro-light-emitting-diode display by a lithographic-fabricated photoresist mold

In this study, a full-color emission red–green–blue(RGB) quantum-dot(QD)-based micro-light-emitting-diode(micro-LED) array with the reduced optical cross-talk effect by a photoresist mold has been demonstrated. The UV micro-LED array is used as an efficient excitation source for the QDs. The aerosol jet technique provides a narrow linewidth on the micrometer scale for a precise jet of QDs on the micro-LEDs. To reduce the optical cross-talk effect,a simple lithography method and photoresist are used to fabricate the mold, which consists of a window for QD jetting and a blocking wall for cross-talk reduction. The cross-talk effect of the well-confined QDs in the window is confirmed by a fluorescence microscope, which shows clear separation between QD pixels. A distributed Bragg reflector is covered on the micro-LED array and the QDs' jetted mold to further increase the reuse of UV light.The enhanced light emission of the QDs is 5%, 32%, and 23% for blue, green, and red QDs, respectively.

Large scale synthesis of full-color emissive carbon dots from a single carbon source by a solvent-free method

Full-color emissive carbon dots(CDs)hold a great promise for various applications,especially in light emitting diodes(LEDs).However,the existing synthetic routes for CDs are carried out in solutions,which suffer from low yields,high pressures,various byproducts,large amounts of waste solvents,and complicated photoluminescence(PL)origins.Therefore,it is necessary to explore large scale synthesis of CDs with high quantum yield(QY)across the entire visible range from a single carbon source by a solvent-free method.In this work,a series of CDs with tunable PL emission from 442 to 621 nm,QY of 23%-56%,and production yield within 34%-72%,are obtained by heating o-phenylenediamine with the catalysis of KCl.Detailed characterizations identify that,the differences between these CDs with respect to the graphitization degree,graphitic nitrogen content,and oxygen-containing functional groups,are responsible for their distinct optical properties,which can be modulated by controlling the deamination and dehydrogenation processes during reactions.Blue,green,yellow,red emissive films,and LEDs are prepared by dispersing the corresponding CDs into polyvinyl alcohol(PVA).All types of white LEDs(WLEDs)with high colorrendering-index(CRI),including warm WLEDs,standard WLEDs,and cool WLEDs,are also fabricated by mixing the red,green,and blue emissive CDs into PVA matrix by the appropriate ratios.

单圈图的邻点全和可区别全染色

用结构分析法完整刻画单圈图U的邻点全和可区别全染色,并得到当U■C_(n)且n■0(mod 3)时,ftndiΣ(U)=Δ(U)+2;其他情况下,ftndiΣ(U)=Δ(U)+1.表明邻点全和可区别全染色猜想在任意单圈图上都成立.

Holographic imaging of full-color real-existing three-dimensional objects with computer-generated sequential kinoforms

We propose a computational method for generating sequential kinoforms of real-existing full-color three- dimensional （3D） objects and realizing high-quality 3D imaging. The depth map and color information are obtained using non-contact full-color 3D measurement system based on binocular vision. The obtained full-color 3D data are decomposed into multiple slices with RGB channels. Sequential kinoforms of each channel are calculated and reconstructed using a Fresnel-diffraction-based algorithm called the dynamic- pseudorandom-phase tomographic computer holography （DPP-TCH）. Color dispersion introduced by different wavelengths is well compensated by zero-padding operation in the red and green channels of object slices. Numerical reconstruction results show that the speckle noise and color-dispersion are well suppressed and that high-quality full-color holographic 3D imaging is feasible. The method is useful for improving the 3D image quality in holographic displays with pixelated phase-type spatial light modulators （SLMs）.

Full-color and less-speckled modified Gerchberg–Saxton algorithm computer-generated hologram floating in a dual-parabolic projection system

This Letter proposes to apply full-color computer-generated holograms to the virtual image projection system so that the viewers can comfortably view floating images. Regarding the spatial division and distribution operation,a modified Gerchberg–Saxton algorithm is used for acquiring the phase infographics, which are input into the spatial light modulator for the reconstructed projection. Such a virtual image projection system could reach the vertical angle of view of 15°–75° and the horizontal angle of view 360°, and the mixed-light modulating proportion contains a 3 m W red light laser, a 2 m W green light laser, and a 2.6 m W blue light laser to achieve the full-color mixed-light proportion with a speckle contrast of 6.65%. The relative diffraction efficiency and root mean square error of the reconstructed image are 95.3% and 0.0524, respectively.

Advances, opportunities, and challenge for full-color emissive carbon dots

Carbon dots(CDs), novel luminescent zero-dimensional carbon nanomaterials, have been widely applied due to their low toxicity, optimal optical properties, and easy modification. However, the current controllable equipment and mechanism explanation of CDs are relatively vague and require urgent resolution.Full-color emission CDs, an essential CDs category, have attracted people’s attention given their light and color-tunable properties. In addition to a wider range of biological and optoelectronic device applications, full-color emission CDs have similar structures and significantly affected the fluorescence mechanism of CDs. At present, few studies have reported on the summary research of CDs emitted by its full color, which greatly limits the development of CDs mechanisms and applications. As such, the present review detailed the full-color CDs development status, to which a suitable method for preparing full-color CDs was presented and the existing fluorescence emission mechanism of full-color CDs was summarized.Herein, we comprehensively introduced full-color CDs applications in biology and optoelectronics. Finally,we made an outlook on the development and potential applications of full-color CDs. The present review aims to contribute novel insights and methods for understanding full-color CDs.

One-pot synthesis of concentration and excitation dual-dependency truly full-color photoluminescence carbon dots

The paper describes a kind of truly full-color photoluminescence(PL)CDs.The CDs were prepared by using one-pot hydrothermally heating citric acid and formamide at 200℃ for 2 h.The CDs have three fluorescent centers at blue,green,and red light region.Their color was regulated through two means,including changing excitation wavelengths or CDs concentrations.The emission maxima changed from blue to red with the increase of excitation wavelengths or CDs concentrations.The full-color PL behavior of the CDs was inherited and conserved in the solid polymer matrix,giving multicolor CDs/polymer films and light emitting diodes(LEDs).White-light LED(WLED)with the CIE coordinate approaching to(0.31,0.32)were also achieved.

液晶偏振体光栅及其在增强现实波导显示中的应用

液晶偏振体光栅是一种基于几何相位的布拉格光栅,具有偏振选择性强、衍射效率高、衍射角大以及制备工艺简单等优点,在增强现实系统中具有潜在的应用前景。本文详细介绍了液晶偏振体光栅的工作原理和光学特性,并对其近年来的研究进展进行了总结。重点讨论了液晶偏振体光栅在解决增强现实波导显示中各种关键性问题的研究,展望了其在增强现实波导显示中的应用前景。最后,总结了目前液晶偏振体光栅应用于波导显示领域存在的问题和发展趋势。

月月竹竹秆变色后全长转录组分析

为探究月月竹竹秆受到光照由绿色变为紫色的分子机制,本研究采集月月竹同一竹节紫色部分(Z)、渐变部分(M)和绿色部分(L)的竹青,提取RNA,利用PacBio Sequel三代全长转录组测序技术,结合生物信息学方法对不同颜色的竹青进行全长转录组分析。结果表明,经过三代测序和数据质量控制,共获得非冗余转录本66961条,长度为500~3000 bp,平均长度1389.22 bp,序列总长度为93.02 Mbp,N50为1830 bp,G+C碱基含量为49.56%。利用NR、Swiss-Prot、COG、GO、KEGG和Pfam数据库对所有转录本进行功能注释,共有56938条转录本被成功注释,占全部转录本的85.03%;49115条转录本被GO注释,其中催化活性、细胞器、代谢过程分别是GO数据库分子功能、细胞组分和生物过程中含转录本最多的项目;28231个转录本被KEGG数据库注释,其中与碳水化合物代谢和基因翻译相关的转录本最多。结合GO注释和KEGG注释,66961条转录本中有381条转录本与光信号的感受、传递以及光调控相关,包括红光和远红光的受体蛋白PHYA、PHYB及信号通路蛋白PIF3、ELF3,蓝光的受体蛋白CRY、ZTL及信号通路蛋白COP1、SPA1、ELF3、GI、HY5等。类黄酮(包括花青素)代谢、叶绿素合成、类胡萝卜素合成等与植物色素合成相关通路分别含有转录本187条、44条和72条。全长转录本共获得2079个转录因子,其中包括18个由35个转录本编码的与花青素合成相关的R2R3MYB转录因子。CNCI、CPC、Pfam、PLEK等数据库同时注释到的长链非编码RNA(LncRNA)6359个,数量高于孝顺竹等其他竹种。本研究获得了高质量的月月竹竹青全长转录组数据,与竹秆变色相关的红光和蓝光受体及光信号传递蛋白,与花青素、叶绿素和类胡萝卜素合成相关的转录因子及长链非编码RNA(LncRNA),为进一步深入分析月月竹竹秆变色机制提供基础。

Quantum-dot and organic hybrid light-emitting diodes employing a blue common layer for simple fabrication of full-color displays

Colloidal quantum-dot(QD)light-emitting diodes(QLEDs)have been in the forefront of future display devices due to their outstanding optoelectronic properties.However,a complicated solution-process for patterning the red,green,and blue QDs deteriorates the QLED performance and limits the resolution of full-color displays.Herein,we report a novel concept of QD–organic hybrid light-emitting diodes by introducing an organic blue common layer(BCL)which is deposited through a common mask over the entire sub-pixels.Benefitted from the optimized device structure,red and green QLEDs retained their color coordinates despite the presence of the BCL.Furthermore,adopting the BCL improved the external quantum efficiency of green and red QLEDs by 38.4%and 11.7%,respectively,due to the Förster resonance energy transfer from the BCL to the adjacent QD layers.With the BCL structure,we could simply demonstrate a full-color QD-organic hybrid device in a single substrate.We believe that this device architecture is practically applicable for easier fabrication of solution-processed,highresolution,and full-color displays with reduced process steps.

基于防松线分割的螺栓松动全角度检测方法

针对现有无法基于防松线分割进行螺栓松动全角度检测的问题,文章开发了一种基于颜色分割和方向矢量运算的方法。首先,利用一种基于Lab和RGB颜色空间转换下的a分量非线性拉伸和R分量最优阈值分割方法分割防松线图像;其次,利用开运算对图像进行形态学操作;再次,通过一种角度递进最小包围方法确定防松线连通域面积最小外接矩形并确定其方向矢量;然后,基于四象限反正切函数和一定调整求解螺栓松动的全角度;最后,设计实验方案验证文中算法的可行性和精度。实验结果表明,检测算法能够实现螺栓0~360°的松动角度检测,且最大相对误差为1.43%,其精度可以满足工程实践需要,具有良好的应用前景。

Full-color quantum dots active matrix display fabricated by ink-jet printing

Making full-color active matrix display based on quantum dot light emitting diodes(AM-QLEDs) via ink-jet printing is attractive in display industry due to QLEDs' wide color gamut and their potential manufacturing advantages of large screen size and low cost. The challenges for realizing AM-QLED display are how to achieve high quality films through ink-jet printing, multi-color patterning, electroluminescence(EL) color purity, and high efficiency. Herein, a 2-inch diagonal full-color AM-QLEDs display with pixel density of 120 pixels per inch(PPI) fabricated by ink-jet printing technique is presented. Driven by a metal oxide TFT(MOTFT) back-panel, the display exhibits a maximum brightness of 400 cd m.2, and a color gamut of 109%(NTSC 1931). The red, green, and blue(RGB) monochrome QLEDs passive matrix panels fabricated by ink-jet printing technique have a current efficiency(CE) of 2.5, 13.9, and 0.30 cd A.1, respectively. To the best of our knowledge, the efficiencies are the highest among passive matrix QLEDs panels made by ink-jet printing technique. The ink-jet printed QDs films show good thickness uniformity due to high viscosity and low volatility of the printable inks, and no cross-contamination between adjacent pixels resulting from the hydrophobic pixel defining layer.