With the growth of photoenergy harvesting and thermal engineering, photothermal materials (PTMs) have attracted substantial interest due to their unique functions such as localized heat generation, ...spatiotemporal thermal controllability, invisibility, and light harvesting capabilities. In particular, π‐conjugated organic PTMs show advantages over inorganic or metallic PTMs in thin film applications due to their large light absorptivity, ease of synthesis and tunability of molecular structures for realizing high NIR absorption, flexibility, and solution processability. This review is intended to provide an overview of organic PTMs, including both molecular and polymeric PTMs. A description of the photothermal (PT) effect and conversion efficiency (ηPT) for organic films is provided. After that, the chemical structure and optical properties of organic PTMs are discussed. Finally, emerging applications of organic PT films from the perspective of spatiotemporal thermal engineering principles are illustrated.
Photothermal conjugated polymer films are reviewed along with their emerging applications from the perspective of their working principles. The state‐of‐the‐art organic molecular and polymeric materials are summarized, and their photothermal conversion efficiencies are correlated to the chemical structures, light absorption, and electronic properties of the films.
While numerous near‐infrared (NIR) materials have emerged, most of them are strongly colored or black due to the absorption band or tails in the visible region. Here, a highly transparent and soluble ...NIR‐absorbing ionic salt, isobutyl‐substituted diimmonium borate (IDI), is synthesized and fabricated, through a solution process, as a thin film that shows a transmittance of over 93% in the whole visible region. A transparent photothermal (PT) film heater is fabricated with the IDI‐doped polymer solution, which shows a photothermal conversion efficiency (ηPT) of 75.2%. Additionally, the prepared PT heater shows a high water evaporation conversion efficiency (ηw) of 68.8% upon exposure to a 1064 nm laser. Furthermore, the transparent IDI film affords the development of a wireless transparent actuator for the first time, generating a bending angle over 75°, with over 2700 bending cycles. The transparent IDI film creates a hot transparent Venus flytrap and a colorful or fluorescent actuator upon the addition of colorants without losing the actuation properties.
A highly transparent near‐infrared (NIR)‐absorbing isobutyl‐substituted diimmonium salt (IDI) selectively absorbs light in the NIR range to provide a transparent photothermal film, IDI‐doped polysulfone (IDIS) film. The IDIS film with 16.7 wt% IDI shows high thermal/moisture resistance, photothermal conversion efficiency, and photodistillation conversion efficiency. By combining this layer with poly(dimethylsiloxane), it becomes a transparent soft actuator that can generate a transparent hot Venus flytrap reversibly.
The review describes the photochromic and fluorescent characteristics of various diarylethene (DAET) derivatives, and presents recent research into their applications. This comprises a discussion of ...the optical characteristics of some DAET-based molecules exhibiting red, green, or blue (RGB) colors or fluorescence. Molecular calculations of the optical properties of DAET interpret intriguing experimental observations and predict photochemical or photophysical properties. In particular, stabilization of HOMO in the BTFO
n (
n
=
1, 2, 3, 4) increases the energy difference between the HOMO and the LUMO, which leads to the blue-shift of absorption and emission bands as the number of oxygen attached to sulfur (
n) increases. Various devices and application studies have been designed as photon-mode systems based on photochemical control of the fluorescence energy. The photochromic DAET materials have shown promise as optical data storage, switching devices, and biological applications such as the development of biomaterial sensors, analysis of biological dynamics, and live cell imaging.
A useful strategy has been developed to fabricate carbon-nanotube–nickel (CNT–Ni) nanocomposites through atomic layer deposition (ALD) of Ni and chemical vapor deposition (CVD) of functionalized ...CNTs. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), were used to characterize the morphology and the structure of as-prepared samples. It was confirmed that the products possess uniform Ni nanoparticles that are constructed by finely controlled deposition of Ni onto oxygen or bromine functionalized CNT surface. Electrochemical studies indicate that the CNT–Ni nanocomposites exhibit high electrocatalytic activity for glucose oxidation in alkaline solutions, which enables the products to be used in enzyme-free electrochemical sensors for glucose determination. It was demonstrated that the CNT–Ni nanocomposite-based glucose biosensor offers a variety of merits, such as a wide linear response window for glucose concentrations of 5μM–2mM, short response time (3s), a low detection limit (2μM), high sensitivity (1384.1μAmM−1cm−2), and good selectivity and repeatability.
•Carbon tetrabromide precursor and Au catalyst can be used for chemical vapor deposition of the CNT which is a good supporting material for ALD of Ni.•Atomic layer deposition (ALD) of Ni is a promising method for preparing a carbon nanotube (CNT)-based Ni nanocomposite•CNT–Ni nanocomposite modified GCE is an excellent electrocatalyst for glucose oxidation.
The incidence of waterborne and foodborne infectious diseases (WFIDs) continues to increase annually, attracting significant global attention. This study examined trends in WFID outbreaks in the ...Republic of Korea over the 5-year period before and during the coronavirus disease 2019 (COVID-19) pandemic and provided foundational data to establish measures for the prevention and control of WFID outbreaks.
We analyzed 2,541 WFID outbreaks from 2017 to 2021 (42,805 cases) that were reported through the Integrated Disease Surveillance System of the Korea Disease Control and Prevention Agency. Outbreaks were defined as the occurrence of gastrointestinal symptoms in ≥2 individuals within a group with temporal and regional epidemiological associations. The related factors associated with WFID outbreaks during the observation period were statistically analyzed.
The total number of WFID outbreaks significantly decreased in 2020 during the COVID-19 pandemic and increased to the pre-pandemic level in 2021. Different patterns were observed for each pathogen. The incidence of Salmonella outbreaks more than doubled, while norovirus outbreaks decreased significantly.
WFID outbreaks in the Republic of Korea showed different patterns before and during the COVID-19 pandemic, influenced by infection control measures and changes in dietary consumption patterns. Outbreaks of some diseases increased, but the infection control measures applied during the pandemic resulted in a significant decrease in the overall number of WFID outbreaks. This highlights the importance of strengthening the management strategies for outbreak prevention through hygiene inspections, long-term monitoring, education, and promotion by conducting multidimensional analyses to understand the complex related factors.
Poly(3-hexylthiophene) (P3HT) films were patterned by a soft lithography technique using a nanopatterned polydimethylsiloxane (PDMS) mold to generate one-dimensional (1D) grating and two-dimensional ...(2D) crossed line pillar patterns. The redox currents (i p) were significantly increased due to the facilitated diffusion of ClO4 − counterions associated with redox processes at the P3HT electrode as analyzing cyclic voltammetry (CV) was performed at different scan rates (ν). It was found that the diffusion coefficient (D f, cm2 s−1) for ion diffusion in the patterned electrode was much larger than that of the pristine P3HT electrode. Furthermore, the value of D f in the 2D electrode was three times higher than that in a pristine film. As a result of such facilitated charge transport, the electrochromic (EC) properties of the patterned P3HT electrode were greatly enhanced and dependent on the dimension of the pattern. Thus, the electrochromic efficiency (E e), including the coloration (E c) and bleaching efficiencies (E b), was higher as the dimension of the pattern was increased; E e was maximized in the 2D patterned P3HT film. In a patterned cell, electrochromic diffraction was reversibly observed with a switching efficiency (R DE) of 2 and 2.5 for the 1D and 2D patterned cells, respectively.
A π-conjugated polymer of propylenedioxythiophene-phenylene (ProDOT-Ph) with a chiral alkyl substituent on the propylene bridge of ProDOT was prepared to explore reversible multiswitching chiral ...conjugated polymers (CCPs) capable of electrochromic, electrofluorochromic, and chirality switching. The chiral assembly of the yellow colored poly(ProDOT-Ph)s (YPCr) was optimized by annealing the YPCr films at 120 °C. From the thermally annealed YPCr films, we demonstrated the electrical switching of chirality, color, and fluorescence in a single device, for the first time, which was precisely controlled electrochemically to achieve highly efficient and reversible switching of chiral assembly at a low working potential. The YPCr films showed electrochromism with a high coloration efficiency of 690 cm2 C–1 by changing color between yellow and blue. The film also exhibited fluorescence switching with a quantum yield change from 3.8 to 0.21 during the reversible electrochemical switching. The chirality of the YPCr, which showed a negative bisignate Cotton effect, was switched reversibly with 97% change in the anisotropy factor (g abs). The multiswitching properties were correlated to the electrochemical switching in chiral assembly of conjugated polymers according to the electrochemical doping/dedoping process. To the best of our knowledge, the change in Cotton effect during the switching is the highest reported value of a chirality tunable polymer without any chiral inducer. In addition, the YPCr showed a sustainable memory effect for both chirality and coloration.
A fluorescent naphthalimide‐tetrazine dyad (NITZ) was examined for electrofluorochromism. The reversible electrochemistry of the tetrazine was accompanied by the fluorescence change through a ...quasi‐complete energy transfer in an electrochemical cell prepared by the mixture of polymer electrolyte and naphthalimide‐tetrazine dyad. Owing to the energy transfer within the dyad (naphthalimide and tetrazine), the fluorescence efficiency of NITZ was much enhanced and the effective fluorophore concentration in this system was much less than other tetrazine based electrofluorochromic device (EFD). Thus the yellow fluorescence of NITZ was switched on and off remarkably even with small quantity of NITZ (1 wt.%) in an EFD upon application of step potentials for different redox state. Furthermore, multi‐color fluorescence switching was achieved by blending a naphthalimide to the electrofluorochromic layer, to show white‐blue‐dark state of fluorescence. Since the tetrazine and naphthalimide units have their emission quenched at different potentials, the emission color could be tuned by quenching emission at selected wavelengths, reversibly, under low working potentials.
Multi‐color fluorescence switching is achieved by blending a naphthalimide to the electrofluorochromic layer, to show white–blue–dark state of fluorescence. The reversible electrochemistry of the tetrazine and naphthalimide is accompanied by the fluorescence change in an electrochemical cell. The emission color can be tuned by quenching emission at selected wavelengths, reversibly, under low working potentials.
Nanopatterning provides facile process to well‐arrayed mesoporous inorganic oxide films at low cost by using readily available pastes and elastomeric nanostamps. The fabricated nanopattern boosted ...the light‐harvesting efficiency of dye‐sensitized solar cells (DSSCs) by a light‐trapping technique. The iodine‐free solid‐state DSSCs showed a 40 % increase in the current density and high efficiency (7.03 %).
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