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Showing papers on "Excimer published in 2021"



Journal ArticleDOI
TL;DR: In this paper, a pyrene-tiaraed pillar[5]arene derivative was synthesized, which showed a concentration-independent intensive excimer emission, applicable to photo-writing.

31 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the behavior of Anthracene (AN) molecules in the excited state by ultrafast time-resolved experiments and mapping of the excited surface through quantum chemical calculations (QM/MM-TDDFT).
Abstract: Excited anthracene is well-known to photodimerize and not to exhibit excimer emission in isotropic organic solvents. Anthracene (AN) forms two types of supramolecular host-guest complexes (2:1 and 2:2, H:G) with the synthetic host octa acid in aqueous medium. Excitation of the 2:2 complex results in intense excimer emission, as reported previously, while the 2:1 complex, as expected, yields only monomer emission. This study includes confirming of host-guest complexation by NMR, probing the host-guest structure by molecular dynamics simulation, following the dynamics AN molecules in the excited state by ultrafast time-resolved experiments, and mapping of the excited surface through quantum chemical calculations (QM/MM-TDDFT method). Importantly, time-resolved emission experiments revealed the excimer emission maximum to be time dependent. This observation is unique and is not in line with the textbook examples of time-independent monomer-excimer emission maxima of aromatics in solution. The presence of at least one intermediate between the monomer and the excimer is inferred from time-resolved area normalized emission spectra. Potential energy curves calculated for the ground and excited states of two adjacent anthracene molecules via the QM/MM-TDDFT method support the model proposed on the basis of time-resolved experiments. The results presented here on the excited-state behavior of a well-investigated aromatic molecule, namely the parent anthracene, establish that the behavior of a molecule drastically changes under confinement. The results presented here have implications on the behavior of molecules in biological systems.

22 citations


Journal ArticleDOI
TL;DR: Using femtosecond transient absorption (fs-TA) and time-resolved impulsive stimulated Raman scattering (TR-ISRS) measurements, the excited-state dynamics of perylene bisimide (PBI) H-aggregates were revealed in this article.
Abstract: Herein, the ultrafast photoinduced dynamics and vibrational coherences for two perylenebisimide (PBI) H-aggregates showcase the formation of the excimer state and the delocalized radical anion state in the excited state, respectively. Using femtosecond transient absorption (fs-TA) and time-resolved impulsive stimulated Raman scattering (TR-ISRS) measurements, we unveiled excited-state dynamics of PBI H-aggregates in two aspects: (1) the intermolecular interactions between PBI units in H-aggregates induce the formation of new excited states, excimer and delocalized radical anion states, and (2) the intermolecular out-of-plane along the aggregate axis and the PBI core C═C stretch Raman modes can be a crucial indicator to understand the coherent exciton dynamics in H-aggregates. Notably, those excited-state Raman modes showed stationary peak positions during the excited-state dynamics. TR-ISRS analysis provides insights into the excited-state vibrational coherences concerning the formation of the excimer and charge-delocalized state in each aggregate system.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the solvent polarity dependent excited state dynamics of the structurally well-defined subphthalocyanine dimer, μ•OSubPc 2, were investigated.
Abstract: Knowledge of the factors controlling excited state dynamics in excitonically coupled dimers and higher aggregates is critical for understanding natural and artificial solar energy conversion. In this work we report ultrafast solvent polarity dependent excited state dynamics of the structurally well‐defined subphthalocyanine dimer, μ‐OSubPc 2 . Stationary electronic spectra demonstrate strong exciton coupling in μ‐OSubPc 2 . Femtosecond transient absorption measurements reveal ultrafast excimer formation from the initially excited exciton, mediated by intramolecular structural evolution. In polar solvents the excimer state decays directly through symmetry breaking charge transfer to form a charge separated state. Charge separation occurs under control of solvent orientational relaxation.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reported the newly synthesized acridine-diehynyl-o-carborane AcE2 and comprehensively compare it to AcE1.
Abstract: Although excimer emission is a useful luminescent phenomenon for fabricating optical sensors and probes, it is difficult to apply excimer emission for film sensors due to critical concentration quenching in the solid state. Therefore, robust molecular designs for solid-state excimer emission are still being explored. One of the key examples is the previously reported acridine-ethynyl-o-carborane AcE1, which showed a bright solid-state excimer emission assisted by characteristic CcageH···N interactions. In this paper, we report the newly synthesized acridine-diehynyl-o-carborane AcE2 and comprehensively compare it to AcE1. Both compounds had the same crystalline packing mode based on dimer formation, resulting in an efficient π-overlapping area and solid-state excimer emission. Variable-temperature photoluminescence (VT-PL) measurements revealed the consecutive thermochromic luminescence of these compounds. Finally, on the basis of the easily accessible spray-coating method, we constructed the thermochromic luminescent sensors on quartz substrates. According to the mechanistic studies, it is demonstrated that the design strategy based on a dimer-induced solid-state excimer should have great potential for applications as a molecular thermometer.

21 citations


Journal ArticleDOI
TL;DR: In this article, a spin-allowed Singlet Exititon Fission (SF) was studied in pure perylene film, where two triplet excitons are created from one singlet exciton.
Abstract: Singlet exciton fission (SF) is a spin-allowed process whereby two triplet excitons are created from one singlet exciton. This phenomenon can offset UV photon energy losses and enhance the overall efficiency in photovoltaic devices. For this purpose, it requires photostable commercially available SF materials. Excited state dynamics in pure perylene film, ease of commercial production, is studied by time-resolved fluorescence and femtosecond transient absorption techniques under different photoexcitation energies. In film, polycrystalline regions contain perylene in H-type aggregate form. SF takes place from higher excited states of these aggregates in ultrafast time scale < 30 fs, reaching a triplet formation quantum yield of 108%. Moreover, at λex = 450 nm singlet fission was detected as a result of two-quantum absorption. Other competing relaxation channels are excimer (1 ps) and dimer radical cation formation (< 30 fs). Excimer radiatively relaxes within 19 ns and radical cation recombines in 3.2 ns. Besides, exciton self-trapping by crystal lattice distortions occurs within hundreds of picosecond. Our results highlight potential of simple-fabricated perylene films with similar properties as high-cost single crystal in SF based photovoltaic applications.

20 citations


Journal ArticleDOI
TL;DR: In this article, a highly selective and sensitive fluorescent ratiometric probe (1) based on pyrene-containing Schiff base for the dection of Cu2+ was synthesized.
Abstract: A highly selective and sensitive fluorescent ratiometric probe (1) based on pyrene-containing Schiff base for the dection of Cu2+ was synthesized. In acetonitrile–HEPES buffer solution (20.0 mM HEPES, 8:2, v/v, pH 7.4), only Cu2+, out of tested common cations, could induce the aggregation of probe 1. Fluorescence analysis showed that the excimer emission band of pyrene groups of probe 1 appeared and gradually increased with the addition of Cu2+. The fluorescent intensity ratio of excimer and monomer (I470/I409) of probe 1 increased 27.8-fold upon the addition of one equiv. of Cu2+ with a detection limit of 20.2 nM (1.28 ppb). The addition of Cu2+ also induced obvious color change and the characteristic peaks of pyrene excimer in UV–vis spectrometra of the relutant solution. Results from the Job plot, metal-binding fluorescent titration, mass spectra experiments and density functional theory calculations indicated a binding ratio of 2:1 (probe 1: Cu2+). In addition, probe 1 showed good potential as a fluorescent visualizing probe for the detection of Cu2+ in living GS cells of epinepheluscoioides.

18 citations


Journal ArticleDOI
TL;DR: This systematic study allowed us to confirm that the excimer chirality rule can be applied to the exciplex dyes: left- and right-handed exciplexes with a twist angle of less than 90° exhibit (−)- and (+)-CPL, respectively.
Abstract: A series of axially chiral binaphthyls and quaternaphthyls possessing two kinds of aromatic fluorophores, such as pyrenyl, perylenyl, and 4-(dimethylamino)phenyl groups, arranged alternately were synthesized by a divergent method. In the excited state, the fluorophores selectively formed a unidirectionally twisted exciplex (excited heterodimer) by a cumulative steric effect and exhibited circularly polarized luminescence (CPL). They are the first examples of a monomolecular exciplex CPL dye. This versatile method for producing exciplex CPL dyes also improved fluorescence intensity, and the CPL properties were not very sensitive to the solvent or to the temperature owing to the conformationally rigid exciplex. This systematic study allowed us to confirm that the excimer chirality rule can be applied to the exciplex dyes: left- and right-handed exciplexes with a twist angle of less than 90 degrees exhibit (-)- and (+)-CPL, respectively.

15 citations


Journal ArticleDOI
TL;DR: In this paper, the formation and evolution of an anthracene excimer as a function of pressure was studied, where the authors designed a crystal based on an Anthracene derivative with dissociative, molecular-ordered dimer assembly.
Abstract: Excimer materials have been widely studied and have generated significant interest for their applications in many optoelectronic devices. However, a thorough investigation of the entire process involved in excimer formation, enhancement, and annihilation in solid materials is still lacking. Here we designed a crystal based on an anthracene derivative with dissociative, molecular-ordered dimer assembly, and studied the formation and evolution of an anthracene excimer as a function of pressure. During the initial stage of pressurization, the fluorescence intensity arising from anthracene monomers gradually decreases. With continued compression, the two anthracene units become increasingly closer allowing strong intermolecular π–π interactions to develop that lead to excimer formation at 3.5 GPa, accompanied with a phase transition. The fluorescence intensity then keeps increasing with pressure and reaches its maximum at 5.6 GPa due to the strengthening of the excimer and the increased structural defects. Meanwhile the fluorescence color shows a continuous redshift, which initially results from conformation planarization and then excimer evolution. After releasing pressure back to ambient conditions, the structural changes in the sample are reversible, while the fluorescence signal preserves some high-pressure features due to the partial retention of the π–π interactions between the anthracene dimers. This study reveals the evolution of an excimer and its intrinsic photophysical properties, and provides guidance for future research on pressure-sensitive fluorescent devices.

15 citations


Journal ArticleDOI
TL;DR: In this paper, an ensemble of four naphthalene molecules linked to a cyclotetrasiloxane ring in an all-cis arrangement were considered. And the properties of different intramolecular excimers were investigated.

Journal ArticleDOI
30 Jun 2021
TL;DR: In this paper, a perylene bisimide folda-dimer (BPBI-CB-1) was fabricated by tethering two PBI moieties to the ortho-carbon positions of a carborane unit.
Abstract: We have fabricated a new perylene bisimide (PBI) folda-dimer (BPBI-CB-1) by tethering two PBI moieties to the ortho-carbon positions of a carborane unit. The synthesized compound adopted distinct c...

Journal ArticleDOI
TL;DR: In this paper, a triarylborane-based [2.2]paracyclophane, g-BPhNMe2-Cp, which contains 2-(dimesityboryl)phenyl and dimethylamino groups at pseudo-gem positions, was shown to exhibit reversible and high-contrast mechanochromic luminescence properties.
Abstract: It is still very challenging to obtain mechanochromic luminescence (MCL) systems that combine high-contrast photoluminescence colour change together with high quantum yields in any morphological state. In this paper, we have disclosed the reversible and high-contrast MCL properties from a triarylborane-based [2.2]paracyclophane, g-BPhNMe2-Cp, which contains 2-(dimesityboryl)phenyl and dimethylamino groups at pseudo-gem positions. With mechanical grinding, this compound exhibits a remarkable fluorescence change from blue fluorescence of the crystalline pristine powder to the green fluorescence of the amorphous ground powder with high fluorescence quantum yields of 0.58 and 0.73, respectively. In addition, the blue fluorescence can be reversibly restored upon fuming the ground powder with solvents. The structural analyses revealed that this compound is featured by a rigid and congested structure, which is helpful to suppress the intermolecular interactions, such as π–π stacking, aggregation, and excimer formation, and consequently enables the intense fluorescence in both morphological phases. The theoretical calculations suggested the remarkable two-colour fluorescence switching of g-BPhNMe2-Cp arising from the alternating excited state conformations formed in the crystalline and amorphous phases due to the different degrees of structural relaxation in the excited state.

Journal ArticleDOI
TL;DR: In this article, femtosecond transient absorption spectroscopy with a near-IR probe was used to unveil a rapid excited-state intramolecular proton transfer reaction.
Abstract: Organic semiconductor materials have recently gained momentum due to their non-toxicity, low cost, and sustainability. Xylindein is a remarkably photostable pigment secreted by fungi that grow on decaying wood, and its relatively strong electronic performance is enabled by π-π stacking and hydrogen-bonding network that promote charge transport. Herein, femtosecond transient absorption spectroscopy with a near-IR probe was used to unveil a rapid excited-state intramolecular proton transfer reaction. Conformational motions potentially lead to a conical intersection that quenches fluorescence in the monomeric state. In concentrated solutions, nascent aggregates exhibit a faster excited state lifetime due to excimer formation, confirmed by the excimer→charge-transfer excited-state absorption band of the xylindein thin film, thus limiting its optoelectronic performance. Therefore, extending the xylindein sidechains with branched alkyl groups may hinder the excimer formation and improve optoelectronic properties of naturally derived materials.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the forces involved in the formation of the benzene excimer and its electron structure, and concluded that the excimer must be characterized as anti-aromatic, with weaker antiaromaticity than the molecular excited singlet.
Abstract: In this Letter we analyze the forces involved in the formation of the benzene excimer and its electron structure, and (anti)aromatic character. We extend our study to excited states in molecular aggregates, the triplet excimer and the benzene-tricyanobenzene exciplex. Electronic wave functions are decomposed in terms of localized excitations and ion-pair configurations through diabatization, and we show that excimer (anti)aromaticity can be described as the linear combination of ground, excited, and ionic molecular states. Our analysis concludes that the benzene excimer must be characterized as antiaromatic, with weaker antiaromaticity than the molecular excited singlet. Moreover, we define a model electronic Hamiltonian for the excimer state and we use it as a building block for the extrapolation of electronic Hamiltonians in molecular aggregates. Benzene multimers present a nonuniform (anti)aromatic character, with the center of the column being antiaromatic and the edges behaving as aromatic. The implications of this work go beyond the study of the excimer, providing a general framework for the calculation and characterization of excited states in aggregates.

Journal ArticleDOI
TL;DR: In this paper, a rational strategy to construct exciplexes with thermally activated delayed fluorescence (TADF) was designed by stacking of the donor and acceptor units of an intramolecular charge transfer (CT) chromophore (TXO-PhCz).

Journal ArticleDOI
TL;DR: The photoinduced dynamics of the tetracene dimer in the gas phase is studied by time-resolved photoionisation and photoion imaging experiments as well as nonadiabatic dynamics simulations in order to obtain mechanistic insight into the excimer formation dynamics.
Abstract: The understanding of excimer formation and its interplay with the singlet-correlated triplet pair state 1(TT) is of high significance for the development of efficient organic electronics. Here, we study the photoinduced dynamics of the tetracene dimer in the gas phase by time-resolved photoionisation and photoion imaging experiments as well as nonadiabatic dynamics simulations in order to obtain mechanistic insight into the excimer formation dynamics. The experiments are performed using a picosecond laser system for excitation into the S2 state and reveal a biexponential time dependence. The time constants, obtained as a function of excess energy, lie in the range between ≈10 ps and 100 ps and are assigned to the relaxation of the excimer on the S1 surface and to its deactivation to the ground state. Simulations of the quantum-classical photodynamics are carried out in the frame of the semi-empirical CISD and TD-lc-DFTB methods. Both theoretical approaches reveal a dominating relaxation pathway that is characterised by the formation of a perfectly stacked excimer. TD-lc-DFTB simulations have also uncovered a second relaxation channel into a less stable dimer conformation in the S1 state. Both methods have consistently shown that the electronic and geometric relaxation to the excimer state is completed in less than 10 ps. The inclusion of doubly excited states in the CISD dynamics and their diabatisation further allowed to observe a transient population of the 1(TT) state, which, however, gets depopulated on a timescale of 8 ps, leading finally to the trapping in the excimer minimum.

Journal ArticleDOI
TL;DR: There are limited data to compare efficacy between recent 308‐nm excimer and conventional 311‐nm narrowband ultraviolet B (NB‐UVB) light in the treatment of vitiligo.
Abstract: BACKGROUND There are limited data to compare efficacy between recent 308-nm excimer and conventional 311-nm narrowband ultraviolet B (NB-UVB) light in the treatment of vitiligo. OBJECTIVE To compare efficacy between 308-nm excimer light and 311-nm NB-UVB in patients with symmetrical vitiligo lesions. METHODS Thirty-six symmetrically paired vitiligo lesions on the same anatomical area were enrolled. One side of the symmetrical lesions was treated with localized 308-nm excimer light, and the opposite side was treated with targeted 311-nm NB-UVB assigned randomly by computer. All lesions were treated with the same protocol, for 48 sessions. Repigmentation was evaluated using Vitiligo Area Scoring Index (VASI) and grading the repigmentation was carried out with three independent investigators. RESULTS Thirty-six symmetrically vitiligo lesions were randomly treated, one side with 308-nm excimer light and the opposite side with 311-nm NB-UVB. After 48 sessions, a significantly lower VASI score and a higher grade of repigmentation were observed in 308-nm excimer light-treated side (P < .001). Nine lesions (25%) treated with 308-nm excimer light and only five lesions (13.89%) treated with 311-nm NB-UVB achieved excellent repigmentation. The 308-nm excimer light and 311-nm NB-UVB-treated sides rapidly obtained 25% repigmentation within a mean of 19.42 sessions and 26.25 sessions, respectively (P = .002). There was no significant difference in mean cumulative UV dosage (P = .065). Side effect as phototoxicity was similar in both sides (P = .08). CONCLUSION Localized 308-nm excimer light appears to be more effective and also more rapidly induces repigmentation than targeted 311-nm NB-UVB for treatment of vitiligo.

Journal ArticleDOI
TL;DR: In this article, the synthesis of argentivorous molecules (L1 and L2) having two chromophores (4-(anthracen-9-yl)benzyl or 4-(pyren-1-yl)-groups and two benzyl groups and the fluorescence properties of their silver complexes in a solution and the solid state are reported.
Abstract: The synthesis of argentivorous molecules (L1 and L2) having two chromophores (4-(anthracen-9-yl)benzyl or 4-(pyren-1-yl)benzyl groups) and two benzyl groups and the fluorescence properties of their silver complexes in a solution and the solid state are reported. A crystallographic approach for the Ag+ complexes with L1 and L2 revealed that the observed fluorescence changes stem from the excimer formation and extinction of fluorescent. Furthermore, binding stabilities of L1 and L2 toward Ag+ ions were estimated by the Ag+-induced UV-vis and PL spectral changes.

Journal ArticleDOI
TL;DR: In this paper, a dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry is presented.
Abstract: We present the rational design, synthesis and spectroscopic characterization of a novel dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry. The rhodamine moiety, excitable at λEx = 315 nm and at λEx = 560 nm in its ring-opened form, provides the pH-responsive fluorophore, while the pH-insensitive phenanthrene, excited at λEx = 315 nm, serves as inert internal reference, The presence of two phenanthrene moieties enables a blue monomer and a blueish green excimer emission at 351 nm and 500 nm, respectively. Opening of the rhodamine B spirolactam ring at an acidic pH below 5.0 (pKa = 2.59 ± 0.04) switches on its emission at 580 nm. Simultaneously, the phenanthrene excimer emission decreases caused by a change in orientation of the phenanthrene units, while the monomer emission is barely affected. This sensor design enables ratiometric measurements in the low acidic pH range utilizing the intensity ratios of the rhodamine B and phenanthrene excimer emission at 580 nm and 500 nm. Alternatively, also the intensity ratios of the rhodamine B and the phenanthrene monomer emission could be exploited or the sum of the phenanthrene monomer and excimer fluorescence. To the best of our knowledge, this is the first report of ratiometric sensing utilizing such a versatile type of tricolor emissive dyad probe bearing phenanthrene moieties and showing phenanthrene monomer and excimer emission.

Journal ArticleDOI
07 May 2021-Langmuir
TL;DR: In this paper, a cationic gemini surfactant referred to as Py-3-12 and composed of two alkylated diammonium bromide head groups, a propyl spacer, and dodecyl and 1-pyrenehexyl hydrophobic tails was synthesized and its critical micellar concentration was determined to equal 0.15 (± 0.02) mM by surface tension and time-resolved fluorescence measurements.
Abstract: A cationic gemini surfactant referred to as Py-3-12 and composed of two alkylated diammonium bromide head groups, a propyl spacer, and dodecyl and 1-pyrenehexyl hydrophobic tails was synthesized. Its critical micellar concentration (CMC) was determined to equal 0.15 (±0.02) mM by surface tension and time-resolved fluorescence measurements. The state of the pyrene molecules, whether they were incorporated inside the Py-3-12 micelles or unassociated in the aqueous solution, was determined by applying the global model-free analysis (MFA) to the fluorescence decays acquired with Py-3-12 aqueous solutions. The unassociated Py-3-12 surfactants emitted as pyrene monomers and showed a long fluorescence lifetime. The excited pyrenyl groups located inside Py-3-12 micelles formed an excimer by a rapid encounter with a ground-state pyrene with an average rate constant equal to 0.69 (±0.06) ns-1. After having the photophysical properties of Py-3-12 in aqueous solution characterized, the number (Nagg) of surfactants per micelle was determined by conducting quenching experiments with dinitrotoluene (DNT). Although DNT is fairly hydrophobic, it was found to partition itself between the Py-3-12 micelles and the aqueous phase. Fluorescence quenching experiments performed on the pyrene monomer and excimer generated by the Py-3-12 aqueous solutions yielded the concentration ([Q]b) of DNT bound to the Py-3-12 micelles and the average number ⟨n⟩d of DNT quenching an excimer by diffusive encounters. A combination of steady-state and time-resolved fluorescence quenching experiments on the excimer yielded the number (⟨n⟩s) of DNT molecules that were bound to the micelles and quenched the excimer in a static manner. A plot of the sum ⟨n⟩d + ⟨n⟩s as a function of [Q]b yielded an Nagg value of 14.0 (±0.2) Py-3-12 units per micelle. This study represents the first example in the literature where Nagg is determined for a micelle, where each surfactant molecule is labeled with pyrene.

Journal ArticleDOI
TL;DR: In this paper, a comparative study of the luminescence properties of solutions and crystals of two isomers: boron difluoride 1-(1′-naphthyl)butanedionate-1,3 (α-NAcBF2) and 1-(2′)-naphthsyl)-butanedionsionate (1, 3) was performed, and an interrelation between the molecular and crystal structure of the studied complexes and their luminecence properties was revealed.
Abstract: A comparative study of the luminescence properties of solutions and crystals of two isomers: boron difluoride 1-(1′-naphthyl)butanedionate-1,3 (α-NAcBF2) and 1-(2′-naphthyl)butanedionate-1,3 (β-NAcBF2) has been performed. An interrelation between the molecular and crystal structure of the studied complexes and their luminescence properties has been revealed. In the α-NAcBF2 molecule, the plane of the naphthyl group was turned by 34.26° relatively to the chelate cycle, while the β-NAcBF2 molecule was planar. The difference in the luminescence properties of the crystals of α-NAcBF2 (452 nm) and β-NAcBF2 (537 nm) was related to different abilities to form excimers. In β-NAcBF2 crystals, J-aggregates consisted of dimers of antiparallel molecules comprising excimer traps. For the crystals and solutions of α-NAcBF2 at 77 K, in addition to phosphorescence, the delayed fluorescence was observed. In case of β-NAcBF2, the delayed fluorescence was detected only for crystals, whereas the phosphorescence – for both crystals and solutions.

Journal ArticleDOI
TL;DR: In this article, up-conversion fluorescence from an electron donor-acceptor exciplex blend composed of the donor 4,4′,4″-Tris(N-3-methylphenyl-N-phenylamino)-triphenylamine (m-MTDATA) and the acceptor 1,3,5-tris(1-phenylon-1H-benzimidazol-2-yl)benzene (TPBi) has been observed and a two-photon absorption (TPA) cross-

Journal ArticleDOI
TL;DR: In this paper, the authors examined the fluorescence emission properties of bulk 4-Cyano-4′-pentylbiphenyl (5CB) and 6CB and found that the specific changes in intensity and wavelength differ between the two liquid crystals and suggest presence of two different molecular conformers as the temperature changes.

Journal ArticleDOI
TL;DR: In this article, a triazole-appended quinoline and naphthyl-based fluorescent sensor was developed from D-glucose and it exhibited excimer quenching in the presence of Cu2+ and Ni2+ ions in an aqueous methanolic solution.


Journal ArticleDOI
TL;DR: In this article, a novel multi-chromophoric system, triad, in which two styrylbenzoquinoline (SBQ) photochromes are connected by a balanced rigid-flexible linker comprising 2,3-naphthylene framework and tetramethylene groups, was designed and synthesized to study an excimer formation in the excited state.


Journal ArticleDOI
TL;DR: In this article, a new morphology for micro/nanocontainer, silicone hemispherical microcup on periodic microswelling structure of silicone rubber, was successfully fabricated by a 193-nm ArF excimer laser.

Journal ArticleDOI
TL;DR: In this paper, a silicone rubber-based biochip for disinfection under deep-UV light exposure was successfully fabricated by an ArF excimer laser, where the periodic micro-swelling structure of silicone rubber was photochemically formed by the ArF laser-induced photodissociation of Si-O bonds.
Abstract: A silicone rubber-based biochip for disinfection under deep-UV light exposure was successfully fabricated by an ArF excimer laser. To fabricate the biochip, periodic micro-swelling structure of silicone rubber was photochemically formed by the ArF excimer laser-induced photodissociation of Si–O bonds of silicone rubber. It was found that the growth rate of the micro-swelling structure could be controlled by varying the laser pulse repetition rate; a slow growth of roughly 100 ms and longer per laser pulse was recognized. In addition, no change of each the micro-swelling height formed at various laser pulse repetition rates was also found in the range of 300–18,000 of laser pulse number. Using such the wide processing window, moreover, the periodic micro-swelling structure could be modified into photoluminescent property by long irradiation of ArF excimer laser, while maintaining the micro-swelling height. Blue photoluminescence from the modified micro-swelling structure was observed under a deep-UV light exposure. Thus, each the periodic micro-swelling structure with various desired heights could be bonded to a flat plate of fused silica glass to have equal gaps. A small amount of solution could be confined in the equal gap to disinfect virus/bacteria in the solution under deep-UV light for analytical application.