Adjustable Optical Properties Research Articles

Firefly-inspired bipolar information indication system actuated by white light

The indication of information in materials is widely used in our daily life, and optical encoding materials are ideal for information loading due to their easily readable nature and adjustable optical properties. However, most of them could only indicate one type of information, either changing or unchanging due to the mutual interference. Inspired by firefly, we present a non-interfering bipolar information indication system capable of indicating both changing and unchanging information. A photochemical afterglow material is incorporated into the photonic crystal matrix through a high-throughput technique called shear-induced ordering technique, which can efficiently produce large-area photonic crystal films. The indication of changing and unchanging information is enabled by two different utilizations of white light by the afterglow material and photonic crystals, respectively, which overcome the limitations of mutual interference. As a proof of concept, this system is used to indicate the changing photodegradation level of mecobalamin (a photosensitive medicine) and unchanging intrinsic drug information with anti-counterfeiting functionality, which is a promising alternative to instantly ascertain the efficacy of medicine at home where conventional assays are impractical.

Controlled Dedoping and Redoping of N‐Doped Poly(benzodifurandione) (n‐PBDF)

AbstractThe doping levels of conjugated polymers significantly influence their conductivity, energetics, and optical properties. Recently, a highly conductive n‐doped polymer called poly (3,7‐dihydrobenzo[1,2‐b:4,5‐b′]difuran‐2,6‐dione) (poly(benzodifurandione), n‐PBDF) is discovered, opening new possibilities for n‐type conducting polymers in printed electronics and other fields. Controlling the doping level of n‐PBDF is of great interest due to its wide range of potential applications. Here controlled dedoping and redoping of n‐PBDF is reported and a mechanistic understating of such a process is provided. Dedoping occurs through electron transfer and proton capture, wherein the ionic dopants, tris(4‐bromophenyl)ammoniumyl hexachloroantimonate (Magic Blue), exhibit efficient proton capture ability and stronger interaction with n‐PBDF, resulting in high dedoping efficiency. Moreover, chemically dedoped PBDF can be redoped using various proton‐coupled electron transfer agents. By manipulating the doping levels of n‐PBDF thin films, ranging from highly doped to dedoped states, the system demonstrates controllable conductivity in five orders of magnitude, adjustable optical properties, and energetics. As a result, these characteristics demonstrate the potential applications of n‐PBDF in organic electrochemical transistors and thermoelectrics.

Numerical simulation of radiative flow with magnetized micropolar nanofluid along a curved stretched surface involving blood silica nanoparticles

Silicon nanoparticles can be used as contrast agents in medical imaging procedures such as computed tomography (CT), magnetic resonance imaging (MRI), and fluorescence imaging. They can aid in the early identification and diagnosis of illnesses by enhancing image sensitivity and resolution through adjustable optical and magnetic properties. Additionally, the knowledge gathered from this research might help create cooling systems for electronics and thermal management applications that are more effective. The focus of current research is on the steady two-dimensional radiative flow of blood with silicon dioxide particles along a curved, stretched surface using a magnetized micropolar nanofluid. Furthermore, the effect of radiation is mentioned. Formulating a mathematical representation of flow equations requires the use of variables in curvilinear form. The leading PDEs are converted into nonlinear ODEs using the non-similarity approach. A bvp4c based on a three-stage Lobatto approach is used to solve the modified nonlinear ODEs. Numerical results for skin factor, couple stress, and local Nusselt number are presented in tabular form, and velocity, microrotation, and temperature fields are presented in graphs. The micro-rotation and temperature field exhibits a declining tendency with rising material parameters, whereas the velocity profile shows the opposite pattern. In addition, the significance of various physical characteristics under various parametric assumptions for a curved, stretched channel is reviewed and emphasized.

Unveiling the physical properties of RbCu3MSe4 (M = Si, Ge) direct band gap semiconductors: A systematic first-principles study

The Silicon and Germanium-based quaternary chalcogenides have remarkable features including their adjustable optical properties and outstanding thermal stability. We explored the complex interplay among the structural, electronic, optical, and thermoelectric characteristics of direct band gap novel RbCu3MSe4 (M = Si, Ge) quaternary chalcogenides by employing the well-known density functional theory. Direct type of band gap at high symmetry Г-point was noticed for both materials. The predicted band gaps of RbCu3SiSe4 and RbCu3GeSe4 are 1.32 eV and 0.73 eV, respectively. Due to the large size of germanium ions compared to silicon, the Ge–Se bonds in RbCu3GeSe4 are more wide-ranging than the Si–Se bonds in RbCu3SiSe4. The complex dielectric function along with other significant optical parameters are investigated and analyzed for their probable employment for optoelectronic applications. These examined materials are suitable to be employed in thermoelectric devices as observed from substantial and outstanding thermoelectric features. The present work could establish the potential employment of these complex systems and would open the way for advanced applications in various fields and technologies.

Near-Infrared Light Emitting Metal Halides: Materials, Mechanisms, and Applications.

Near-Infrared (NIR) light emitting metal halides are emerging as a new generation of optical materials owing to their appealing features, which include low-cost synthesis, solution processability, and adjustable optical properties. NIR-emitting perovskite-based light-emitting diodes (LEDs) have reached an external quantum efficiency (EQE) of over 20% and a device stability of over 10,000 h. Such results have sparked an interest in exploring new NIR metal halide emitters. In this review, several different types of NIR-emitting metal halides, including lead/tin bromide/iodide perovskites, lanthanide ions doped/based metal halides, double perovskites, low dimensional hybrid and Bi3+/Sb3+/Cr3+ doped metal halides, are summarized, and their recent advancement is assessed. The characteristics and mechanisms of narrow-band or broadband NIR luminescence in all these materials are discussed in detail. Also, the various applications of NIR-emitting metal halides are highlighted and an outlook for the field is provided.

Boron- and Oxygen-Doped π-Extended Helical Nanographene with Circularly Polarised Thermally Activated Delayed Fluorescence.

Helical nanographenes have garnered substantial attention owing to their finely adjustable optical and semiconducting properties. The strategic integration of both helicity and heteroatoms into the nanographene structure, facilitated by a boron-oxygen-based multiple resonance (MR) thermally activated delayed fluorescence (TADF), elevates its photophysical and chiroptical features. This signifies the introduction of an elegant category of helical nanographene that combines optical (TADF) and chiroptical (CPL) features. In this direction, we report the synthesis, optical, and chiroptical properties of boron, oxygen-doped Π-extended helical nanographene. The π-extension induces distortion in the DOBNA-incorporated nanographene, endowing a pair of helicenes, (P)-B2NG, and (M)-B2NG exhibiting circularly polarized luminescence with glum of -2.3×10-3 and +2.5×10-3, respectively. B2NG exhibited MR-TADF with a lifetime below 5 μs, and a reasonably high fluorescence quantum yield (50 %). Our molecular design enriches the optical and chiroptical properties of nanographenes and opens up new opportunities in multidisciplinary fields.

Bioinspired electrically stable, optically tunable thermal management electronic skin via interfacial self-assembly

The skin is the largest organ in the human body and serves vital functions such as sensation, thermal management, and protection. While electronic skin (E-skin) has made significant progress in sensory functions, achieving adaptive thermal management akin to human skin has remained a challenge. Drawing inspiration from squid skin, we have developed a hybrid electronic-photonic skin (hEP-skin) using an elastomer semi-embedded with aligned silver nanowires through interfacial self-assembly. With mechanically adjustable optical properties, the hEP-skin demonstrates adaptive thermal management abilities, warming in the range of +3.5°C for heat preservation and cooling in the range of −4.2°C for passive cooling. Furthermore, it exhibits an ultra-stable high electrical conductivity of ∼4.5×104 S/cm, even under stretching, bending or torsional deformations over 10,000 cycles. As a proof of demonstration, the hEP-skin successfully integrates stretchable light-emitting electronic skin with adaptive thermal management photonic skin.

Facile preparation, optical mechanism elaboration, and bio-imaging application of fluorescent cellulose nanocrystals with tunable emission wavelength

Interfacing cellulose nanocrystals (CNCs) with fluorescent materials provides more possibilities for constructing of sensory/imaging platforms in biomedical applications. In this work, by harnessing the efficient extraction accompanied modification of CNCs and adjustable optical properties of carbon dots (CDs), we report the constructions and emission wavelength tuning of fluorescent CNCs (F-CNCs) composed of CNC nano-scaffolds and CDs. The as-prepared CNCs are densely decorated with citric acid (CA), which plays the role of carbon source for the in-situ synthesis of CDs on CNCs. For the F-CNCs carrying blue, green, and red emissive CDs, ethylenediamine (EDA), urea, and thiourea are the N or N/S sources. Fingerprints of chemical groups, morphological characters, and redox activities are resolved to elaborate the optical mechanisms of CDs with varying emission colors. The emission wavelength is adjusted by either changing the particle size or introducing new emission centers. Both are primarily achieved via precursor engineering. The F-CNCs reveal quantum yields (QYs) >22 % and negligible fluorescence quenching (< 6 %) upon continuous excitation as long as 24 h. Benefited from their cell membrane penetration capability, the F-CNCs with different emission wavelengths were challenged for multiplexed cytoplasm imaging.

Combining heterointerface/surface oxygen vacancies engineering of bismuth oxide to synergistically improve its solar water splitting performance

Solar-powered photoelectrochemical (PEC) water splitting is recognized as a strategy for addressing fossil resource and global warming concerns. The purpose of this paper is to demonstrate for the first time a facile method to fabricate dendritic nanostructured (DN) Bi:Bi2O3 heterointerface engineering junctions that possess abundant surface oxygen vacancies (OVs, DN Bi:Bi2O3-OVs/FTO), with outstanding PEC performance. The surface OVs serve as shallow donors and active reaction sites, whereas the Bi-metal bridges are used for fast electron transport. Furthermore, surface OVs can enhance the surface features of Bi:Bi2O3 heterointerfaces and boost their electrical conductivity and donor density. This greatly enhances electrolyte ion and electron mobility, resulting in rapid water oxidation reactions at the Bi:Bi2O3/electrolyte interfaces. By combining the Bi:Bi2O3 heterointerface junction and surface OVs, we are able to create an effective photoanode with 95 % charge injection efficiency, applied bias photon-to-current efficiency (ABPE) of 0.112 %, and a photocurrent response of 0.334 mA.cm−2 at 1.23 V vs. the reversible hydrogen electrode (RHE), which represents improvements of about 4.5 and 10 folds over that of pure DN Bi2O3 photoanode. It is possible to construct a variety of unique nanostructured electrodes with adjustable optical and electronic properties to be used in solar cells, energy storage, and PEC applications.

Recent Progress of Organic–Inorganic Hybrid Perovskite Quantum Dots: Preparation, Optical Regulation, and Application in Light‐Emitting Diodes

AbstractOrganic–inorganic hybrid perovskite quantum dots (QIHP‐QDs) have aroused widespread interest due to their superior photoelectric performance, quantum confinement effect, excellent photoelectric property, color‐tunability, and high photoluminescence quantum yield (PLQY) especially for QD‐based light‐emitting diodes (QLEDs). It is worth noting that a diverse selection of organic cations brings more adjustable optical properties to OIHP‐QDs compared with all‐inorganic perovskite QDs; thus the research on OIHP‐QDs has become a hit subject over recent years. This review summarizes the latest progress in synthesis strategy and optical property regulation of OIHP‐QDs in conjunction with the recent developments of their application in QLEDs. In addition, the current challenges limiting the applicability of QIHP‐QDs are discussed, and the development of OIHP‐QDs in the future is proposed.

Antenna effect of perylene-sensitized up-conversion luminescent material amplifies the signal of electrochemiluminescence biosensor platform for the ultra-sensitive detection of enrofloxacin

Recently, up-conversion luminescent (UCL) materials have caught extensive sight on account of their excellent biocompatibility and weak automatic fluorescence background, but the low optical signal makes researchers shy away. Organic dye-sensitized UCL materials can improve the low optical signal drawback of UCL and rejuvenate it with adjustable optical properties and unique antenna effects. In this work, an efficient, simple and selective electrochemiluminescence (ECL) sensing platform was developed for determination of enrofloxacin (ENR). 3,4,9,10-perylene tetracarboxylic acid (PTCA) was successfully used as an “antenna” to improve the ECL performance of the UCL nanoparticles (PEI-NaYF4: Yb, Er) due to its appropriate excitation spectrum position and superior electron transfer rate. The specific recognition function of the aptamer enabled the sensor to eliminate the interference from conspecific impurity. In the presence of ENR, the specific combination of ENR with aptamer made the aptamer fall from surface of the electrode, thus we could see a considerable enhancement of signal. Under the most favourable conditions, the aptasensor based on antenna effect displayed a wide detection range (1.0 × 10−14∼1.0 × 10−6 M), low limit of detection (LOD = 3.0 × 10−15 M) and receivable recoveries (96.0%–102.4%) during water samples analysis. At this point, antenna effect provides a powerful strategy to expand the application of UCL in the field of ECL biosensing.

Selective anisotropic growth of Bi2S3 nanoparticles with adjustable optical properties.

We report on the controlled synthesis and functionalization in two steps of elongated Bi2S3 nanoparticles within a wide range of sizes. First, we show the effect of the temperature and reaction time on the synthesis of two series of nanoparticles by the reaction of thioacetamide with bismuth(III) neodecanoate in the presence of organic surfactants. At 105 °C and long reaction times, nanoneedles of about 45 nm in length containing larger crystallites are obtained, while highly crystalline nanorods of about 30 nm in length are dominant at 165 °C, regardless of the reaction time. The optical properties of both types of nanoparticles show an enhancement of the band gap compared to bulk Bi2S3. This is likely to arise from quantum confinement effects caused by the small particle dimensions relative to the typical exciton size, together with an increase in near-infrared absorption due to the anisotropic particle shape. Second, a ligand exchange approach has been developed to transfer the Bi2S3 nanoparticles to aqueous solutions by grafting dimercaptosuccinic acid onto the surface of the particles. The as-prepared coated nanoparticles show good stability in water, in a wide biological pH range, and in phosphate-buffered saline solutions. Overall, this work highlights the controlled design at all levels - from the inorganic core to the organic surface coating - of elongated Bi2S3 nanoparticles, leading to a tunable optical response by tuning their morphology and size.

Synthesis of millimeter-sized MoxW(1−x) S2ySe2(1−y)monolayer alloys with adjustable optical and electrical properties and their magnetic doping

Based on a new liquid phase edge epitaxy (LPEE) method, we have grown millimeter-sized quaternary MoxW(1−x) S2ySe2(1−y) monolayer films and M-doped MoxW(1−x) S2ySe2(1−y) monolayers (M: Fe, Co, and Ni).

Ultrabroad reflective polarization converter in terahertz based on circular-end graphene rectangles

Polarization is one of the basic properties of electromagnetic waves. Control and manipulation of polarization by devices based on metasurfaces have versatile applications in modern technologies. We propose a broadband reflective cross-polarization converter in the THz region based on an array of circular-end graphene rectangular patches. Efficient polarization conversion was accomplished through dipole graphene plasmon resonances (DGPRs), either along the long or the short axis of the graphene patches. As the width of the rectangles increased, a new longitudinal dipole mode appeared due to the circular ends of the patches. It grew strong and connected the original DGPRs, constructing an ultrabroad conversion band with efficiency over 94% from approximately 2.5 to 5.0 THz. The relative bandwidth was nearly 66%, surpassing most broadband converters reported. Such broad conversion held for a wide incident angle range as DGPRs were robust to the direction of irradiation. Due to the adjustable optical properties of graphene, the broad conversion band can be tuned. These findings are inspiring for creating broadband, compact and dynamic optoelectrical devices in the THz range.

AIB3IIC3IIIQ8VI: A New Family for the Design of Infrared Nonlinear Optical Materials by Coupling Octahedra and Tetrahedra Units.

Large second-harmonic generation (SHG) response and broad band gap are two important and competitive parameters. It is difficult to balance them out in one material. In this work, by coupling alkali earth metal (AEM) octahedra with large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap and nonlinear optical (NLO)-active tetrahedra units, nine noncentrosymmetric (NCS) compounds, belonging to a new quaternary chalcogenide family AIB3IIC3IIIQ8VI with unique windmill-like [Mg3M3IIIQ24] (MIII = Al, Ga; Q = S, Se) units constructed by alternated [MgQ6] octahedra and [MIIIQ4] tetrahedra, are rationally designed and fabricated. The compounds show a stable structural framework but adjustable optical properties. Among them, NaMg3Ga3Se8 shows a large SHG response (∼1 × AgGaS2 (AGS)), wide band gap (in selenide) (2.77 eV), high laser-induced damage threshold (LIDT) (∼2.3 × AGS), and suitable birefringence (0.079@546 nm). It should be a potential candidate for infrared (IR) nonlinear optical (NLO) materials. The results enrich the chemical diversity of chalcogenides and open an avenue for the development of new IR NLO materials through the octahedra and tetrahedra coupled strategy.

1+1>2: Fiber Synergy in Aggregation-Induced Emission.

Mesoscopic aggregate is important to transfer or even amplify the molecular information in macroscopic materials. As an important branch of aggregate science, aggregation-induced emissive luminogens (AIEgens) often show slight or even no emission in solutions but exhibit bright emission when they aggregate, which open a new avenue for the practical applications. Due to the flexible and rotor structure of AIEgens, the aggregate structure of AIEgens is highly sensitive to the surrounding microenvironment, resulting in adjustable optical properties. Fibers integrated of a multiplicity of functional components are ideal carriers to control the aggregation processes, further assembly of fibers produces large-scale fabrics with amplified functions and practical values. In this Concept article, we focus on the latest advances on the synergy between "AIE+Fiber" for the boosted performance that beyond AIE, and their applications are presented and abstracted out to stimulate new ideas for developing "AIE+Fiber" systems.

Small Size, Big Impact: Recent Progress in Bottom-Up Synthesized Nanographenes for Optoelectronic and Energy Applications.

Bottom‐up synthesized graphene nanostructures, including 0D graphene quantum dots and 1D graphene nanoribbons, have recently emerged as promising candidates for efficient, green optoelectronic, and energy storage applications. The versatility in their molecular structures offers a large and novel library of nanographenes with excellent and adjustable optical, electronic, and catalytic properties. In this minireview, recent progress on the fundamental understanding of the properties of different graphene nanostructures, and their state‐of‐the‐art applications in optoelectronics and energy storage are summarized. The properties of pristine nanographenes, including high emissivity and intriguing blinking effect in graphene quantum dots, superior charge transport properties in graphene nanoribbons, and edge‐specific electrochemistry in various graphene nanostructures, are highlighted. Furthermore, it is shown that emerging nanographene‐2D material‐based van der Waals heterostructures provide an exciting opportunity for efficient green optoelectronics with tunable characteristics. Finally, challenges and opportunities of the field are highlighted by offering guidelines for future combined efforts in the synthesis, assembly, spectroscopic, and electrical studies as well as (nano)fabrication to boost the progress toward advanced device applications.

Nanotechnologies for Preparation and Application of Metallic Nickel

Nanostructured nickel exhibits substantial surface area per unit volume and adjustable optical, electronic, magnetic, and biological properties, that makes nanofabricated nickel highly attractive as regards to its practical application in different fields of chemistry. Technologies on nickel nanomaterials including their simple preparation and modern application are summarized in this review.

Development and Validation of Robust and Cost-Effective Liquid Heterogeneous Phantom for Time Domain Near-Infrared Optical Tomography.

Diffused light imaging techniques, such as near-infrared optical tomography (NIROT), require a stable platform for testing and validation that imitates tissue optical properties. The aim of this work was to build a robust, but flexible liquid phantom for BORL time-domain NIROT system Pioneer. The phantom was designed to assess penetration depth and resolution of the system, and to provide a heterogeneous inner structure that can be changed in controllable manner with adjustable optical properties. We used only in-house produced 3D-printed elements and mechanics of a budget 3D-printer to build the phantom, and managed to keep the overall costs below $500. We achieved stable and repeatable movement of an arbitrary structure in 3+1 degree of freedom inside the phantom and demonstrated its performance in a series of tests. Thus, we presented a universal and cost-effective solution for testing NIROT, that can be easily customised to various systems or testing paradigms.

NIR-Excitable PEG-Modified Au Nanorods for Photothermal Therapy of Cervical Cancer

Gold (Au) nanorods (NRs) have been extensively used in applications in biomedical fields, thanks to their adjustable optical and stable chemical properties. Especially for the photothermal therapy (PTT) of cancer, Au NRs show an excellent thermal effect in the near-infrared (NIR) light range. However, cetyltrimethylammonium bromide (CTAB), which has been traditionally widely used for the synthesis of Au NRs, is generally cytotoxic. Surface modification is one of the ideal nanotechnologies to reduce toxicity and enhance the biocompatibility of CTAB-stabilized Au NRs. Herein, we designed an NIR-I-excitable photothermal theranostic nanoplatform Au@PEG NRs via modifying Au NRs with [1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)]] (molecular weight: 2000; DSPE-mPEG2000). The results show that due to the PEG-layer protection, Au@PEG NRs exhibit superior biocompatibility (cell survival rate > 90%) and chemical stability. Meanwhile, Au@PEG NRs exhibited excellent biocompatibility via a hemolysis test, blood routine assays, and histological examinations (H&E). The absorption spectra of Au@PEG NRs showed a negligible change in the different pH (5.5–7.5) solutions, and the in vitro maximum heat dissipation photothermal conversion efficiency was 36.83%. In vivo PTT effects of Au@PEG NRs on a cervical tumor can reach 58.8 °C. The intracellular localization suggests the efficient cellular uptake of Au@PEG NRs. The fact that in vitro Au@PEG NRs assisted PTT under laser irradiation (793 nm) extremely ablates HeLa cells. The ultrastable Au@PEG NRs have significant potential for PTT application of cervical cancer.