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Facile color tuning of thermally activated delayed fluorescence by substituted ortho-carbazole-appended triarylboron emitters
摘要： We report the facile tuning of the emission color of thermally-activated delayed fluorescent (TADF) emitters based on an ortho-carbazole-appended triarylboron. A series of ortho-carbazole-appended triarylboron compounds (2-7) are prepared by introducing various electron-accepting substituents, such as phenyl, pyridyl, pyrimidyl, diphenylphosphine oxide, cyano, and dimesitylboryl groups, to the phenylene ring of the dimesitylphenylboryl (PhBMes2) acceptor moiety in the parent ortho-carbazole-appended triarylboron (CzoB, 1). The X-ray crystal structure of the cyano-substituted compound 6 confirms the twisted connectivity between the Cz and phenylene rings. All the compounds exhibit strong TADF (ΦPL = 48-93% in toluene) with large delayed portions. In particular, the emission bands gradually undergo bathochromic shifts from blue (l PL = 463 nm for 1) to greenish yellow (l PL = 532 nm for 7) depending on the electron-accepting substituents. Electrochemical studies show that the greater stabilization of the LUMO level compared to the HOMO is responsible for the red shifts of the emission. Theoretical studies further support the observed bathochromic shifts in the emission, as well as the small energy splittings (D EST) between the excited singlet and triplet states that afford the efficient TADF.
关键词： Ortho donor-acceptor,Color tuning,Triarylboron,Thermally activated delayed fluorescence
更新于2025-11-14 15:28:36
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Stretchable and Higha??Adhesive Plasmonic Metasheet Using Al Subwavelength Grating Embedded in an Elastomer Nanosheet
摘要： Plasmonic metasurfaces have attracted much attention for use in device applications over the past decade. Dynamic color tuning (DCT), where the displacement of periodic nanostructures is controlled to generate different colors in real time, is one of the great possibilities of plasmonic metasurfaces for optical strain sensors or display devices. In this study, an Al metasurface embedded in an elastomer nanosheet with film thickness 400 nm is fabricated by means of sacrificial release using a polyvinyl alcohol sacrificial layer. This plasmonic metasheet shows not only the seven colors produced by surface plasmons, but also DCT by stretching the elastomer nanosheet. Each pixel, designed with a grating period of 300–600 nm, emits the bright colors expected in electromagnetic simulation. Moreover, stretching the plasmonic metasheet demonstrates DCT from 495 to 660 nm in the visible light range. The freestanding metasheet with maximum thickness 400 nm may be easily integrated into any active device by post-processing transfer. Stretching the metasheet requires an estimated × 10?3 lower force than previously reported for plasmonic metasurfaces, owing to a film thickness of only several hundreds of nanometers. These results facilitate the realization of microdevices with novel capabilities based on plasmonic metamaterials.
关键词： plasmonic metamaterials,elastomer nanosheets,dynamic color tuning,subwavelength gratings,surface plasmons
更新于2025-09-23 15:21:01
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Colors with plasmonic nanostructures: A full-spectrum review
摘要： Since ancient times, plasmonic structural coloring has inspired humanity; glassmakers achieved vibrant colors by doping glass with metal nanoparticles to craft beautiful objects such as the Roman Lycurgus cup and stained glass. These lovely color ?ltering effects are a consequence of the resonant coupling of light and free electrons in metal nanoparticles, known as surface plasmons. Thanks to the continuing improvement of nanofabrication technology, the dimensions of nanoparticles and structures can now be precisely engineered to form “optical nanoantennas,” allowing for control of optical response at an unprecedented level. Recently, the ?eld of plasmonic structural coloring has seen extensive growth. In this review, we provide an up-to-date overview of various plasmonic color ?ltering approaches and highlight their uses in a broad palette of applications. Various surface plasmon resonance modes employed in the plasmonic color ?ltering effect are discussed. We ?rst review the development of the pioneering static plasmonic colors achieved with invariant optical nanoantennas and ambient environment, then we address a variety of emerging approaches that enable dynamic color tuning, erasing, and restoring. These dynamic color ?lters are capable of actively changing the ?ltered colors and carrying more color information states than the static systems. Thus, they open an avenue to high-density data storage, information encryption, and plasmonic information processing. Finally, we discuss the challenges and future perspectives in this exciting research area.
关键词： information encryption,surface plasmons,dynamic color tuning,plasmonic information processing,plasmonic structural coloring,optical nanoantennas,high-density data storage
更新于2025-09-23 15:19:57
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Tuning the Emission Colors of Self-Assembled Quantum Dot Monolayers via One-Step Heat Treatment for Display Applications
摘要： Homogeneously self-assembled colloidal semiconductor quantum dot monolayers (QD-SAMs) over large areas are promising materials for thin film optoelectronic device applications, especially for display. Although tuning of emission colors from QDs is generally achieved during wet chemical synthesis and before monolayer formation, we propose in this study a simple and effective method to adjust emission colors after the formation of QD-SAMs by a simple one-step heat treatment. CdSe-based core/shell or core/double shell structured QDs (CdSe/ZnS, CdSe/CdZnS, and CdSe/CdS/ZnS) covered with an optimal set of hydrophobic ligands can form homogeneous and stable QD-SAMs at the air-water interface. The QD-SAMs are subsequently transferred onto hydrophobized glass substrates by the Langmuir-Schaefer (LS) method and thermally treated in air. We found a blueshift of more than 35 nm for the emission wavelength (red to green) by a thermal treatment at 280 °C for 150 min with CdSe/ZnS QD-SAMs. The color can be adjusted by changing the heating temperature and the treatment time. The wavelength shift is in the order of CdSe/ZnS(4L) > CdSe/ZnS(6L) = (CdSe/CdZnS) > (CdSe/CdS/ZnS). The energy dispersive X-ray (EDX) microanalysis of a single QD reveals that the blueshift is mainly caused by atomic diffusion-induced alloying of core/shell type QDs. The main problem of this method is the decreasing emission intensity caused by oxidation during the heat treatment; however, this problem can be solved by use of a SiO2 protective coating on the QD-SAMs. We believe that this simple technique is useful for manufacturing RGB-colored ultrathin QD-SAM films for QDs displays such as QD film display, QD color-filter display, and QD light emitting diode.
关键词： QD Display,Quantum dots,Color tuning,Self-assembled monolayer,atomic diffusion-induced alloying,Thermal treatment
更新于2025-09-23 15:19:57
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Solution-processed, top-emitting, microcavity polymer light-emitting diodes for the pure red, green, blue and near white emission
摘要： Top-emitting microcavity polymer light-emitting diodes (TMPLEDs) are of great significance for active matrix PLED displays with high color purity. However, the complex device structures of high efficiency microcavity organic light-emitting diodes fabricated by the full vapor deposition technology are not suitable to the solution processed PLEDs. The solution-processed TMPLEDs with simple device structures are promising candidates as the large-area, mass production display techniques. In this work, three strategies were used to apply microcavity into PLEDs: (1) double Ag electrodes performed as the mirrors of cavity, instead of multi-layer Bragg reflector, which simplified the device structure and fabrication process; (2) three solution processed functional layers were specially designed for avoiding the inter-infiltration between the different solution and improve the interface contacts; (3) high order microcavities were utilized according to the optical simulation results, in which thick EMLs benefited to thickness control and reproductivity. As results, the full-color emission including pure red, green, blue was realized, and quasi-white light was also achieved from single polymer emitting material. The achievement of color purity always sacrifices part of current efficiency (CE) due to the spectra narrowing, while the higher CE of green TMPLED (10.08 cd/A) than that of non-cavity PLED (∽8.60 cd/A) cast lights on the future improvement.
关键词： Top-emitting,Interface Engineering,Color Tuning,Polymer Light-Emitting Diodes,Solution-processed,Microcavity
更新于2025-09-16 10:30:52
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Full-color persistent luminescence tuning: A marriage of perovskite quantum dots and lanthanide ions
摘要： In modern society, luminescent materials capable of emitting various colored lights are critically important for lighting and display systems. As a typical kind of luminescent materials, the persistent luminescence phosphors have been widely investigated as night-light vision materials due to their many significant applications such as emergency route signage and security signals, bio-labels, photocatalysts, anti-counterfeiting, optical sensors, and optical data storage. However, realizing multicolored persistent luminescence phosphors has been a long-standing challenge, thus posing a serious problem in their practical applications. In a recent publication in Angewandte Chemie International Edition, Prof. Xueyuan Chen and co-workers demonstrated a simple but effective approach to fine-tuning the persistent luminescence colors, based upon the composites of lanthanide ions doped CaAl2O4:Eu2+,Nd3+ (CAO) blue persistent phosphors with all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite quantum dots (PeQDs). With the help of the radiative energy transfer from CAO blue persistent phosphors to CsPbX3 PeQDs, the persistent luminescence colors can be precisely controlled through tailoring of the PeQDs bandgap. The approach allowed access to full-spectrum persistent luminescence with wavelengths covering the entire visible spectral range by single-wavelength excitation, thus offering new opportunities for persistent luminescence materials in many important emerging applications.
关键词： persistent luminescence,lanthanide ions,full-color tuning,perovskite quantum dots
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - Seoul, Korea (South) (2019.1.27-2019.1.31)] 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - Diversified and Precise Plasmonic Color Tuning by Three-Dimensional Air-Gap Nanocavities
摘要： We report a new arrayed three-dimensional (3D) air-gap nanocavities with multiple tunable geometrical parameters. Light is tightly confined into the nanocavities and strong surface-plasmon coupling is introduced, realizing narrow band resonance. Vivid plasmonic colors are generated, and can be tuned by multiple geometrical parameters of the 3D nanocavities, including shapes, separations, and heights. What’s more, the surface-plasmon coupling resonance has different dependence on different variable geometrical parameters. So, multi-dimensional color tuning with different spectral sensitivities is realized by proper and precise structural design, leading to both broad gamut and sophisticated plasmonic color printing at the optical diffraction limit.
关键词： plasmonic color tuning,surface-plasmon coupling,color printing,optical diffraction limit,3D air-gap nanocavities
更新于2025-09-12 10:27:22
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Enhanced photovoltaic performance of Y2O3:Ho3+/Yb3+ upconversion nanophosphor based DSSC and investigation of color tunability in Ho3+/Tm3+/Yb3+ tridoped Y2O3
摘要： The present study reports the upconversion (UC) based color tuning in Y2O3:Ho3+/Yb3+, Y2O3:Tm3+/Yb3+ and Y2O3:Tm3+/Ho3+/Yb3+ phosphors synthesized through complex based precursor solution method. The Y2O3:Ho3+/Yb3+ phosphor emits intense green and weak red colors whereas the Y2O3:Tm3+/Yb3+ emits NIR and blue colors on excitation with 976 nm. The impact of the enhancement in the concentration of Yb3+ on the color point of codoped as well as tridoped phosphors has been studied in detail. When Y2O3:Tm3+/Ho3+/Yb3+ phosphor is excited by 976 nm laser, the phosphor emits dominant green color. This is due to energy transfer from Tm3+ to Ho3+ ions. The increase in the concentration of Yb3+ ion leads to a color tunability not only in the co-doped but also in the tridoped phosphors. Furthermore, we have incorporated Y2O3:Ho3+,Yb3+ UC phosphor into TiO2 electrode to form an UC based DSSC for converting near IR (NIR) light into visible where DSSCs typically have high sensitivity. The short-circuit current density (Jsc) as well as the open-circuit voltage (Voc) of the UC-TiO2 based cell was found to be 8.46% and 5.18% higher which in turn, resulted into a 10.33% enhancement in power conversion efficiency as compared to that of bare TiO2 based DSSC. Thus, the UC based Y2O3:Ho3+/Yb3+ may be useful in color tunability and DSSC applications.
关键词： Upconversion,Photovoltaic performance,Color tuning,DSSC,Y2O3:Ho3+/Yb3+
更新于2025-09-11 14:15:04
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Simultaneously tuning emission color and realizing optical thermometry via efficient Tb3+→Eu3+ energy transfer in whitlockite-type phosphate multifunctional phosphors
摘要： A series of Ca8ZnLa(PO4)7 (CZLPO) phosphors doped with Tb3+ and Eu3+ have been synthesized using a high-temperature solid-state method. The XRD pattern verifies that all prepared samples are attributed to whitlockite-type structure of β-Ca3(PO4)2 with R3c (161) space group. Under 366 nm excitation, the CZLPO: Tb3+, Eu3+ phosphors exhibit a tunable multi-color emission owing to energy transfer from Tb3+ to Eu3+ via a quadrupole-quadrupole interaction mechanism. The emission colors of the phosphors could be modulated from green to red under NUV (366 nm) excitation due to efficient Tb3+/Eu3+ energy transfer. The fluorescence intensity ratio (I542nm/I611nm) for the Tb3+/Eu3+ of this material displayed excellent temperature sensing properties between 298 and 498 K. Moreover, it was found that the intensity ratio was unchanged when the temperature was cycled between 298 and 498 K, thus demonstrating the recyclability of this system. These results show that CZLPO: Tb3+, Eu3+ phosphors have potential as high performance multifunctional materials for solid state lighting and temperature sensing applications.
关键词： Ca8ZnLa(PO4)7: Tb3+,Energy transfer,Eu3+,Color tuning,Temperature sensing
更新于2025-09-10 09:29:36