Two-photon Absorption Chromophores Research Articles

Facile synthesis, optical properties and theoretical calculation of two novel two-photon absorption chromophores

Two heterocycle-based derivatives that can be used as two-photon absorption chromophore, 9-butyl-3-(2, 6-diphenylpyridin-4-yl)-9H-carbazole ( BDPYC) and 9-butyl-3-(4-(2, 6-diphenylpyridin-4-yl)styryl)-9H-carbazole ( BDPSC) have been successfully synthesized and fully characterized by elemental analysis, IR, 1H NMR, 13C NMR and MS. The molecules possess D-π-A structures, but have different π bridge. The 9-butylcarbazole is used as a donor (D), and the pyridine ring is used as an acceptor (A). One- and two-photon absorption and excited fluorescence properties in various solvents were experimentally investigated. Two-photon initiated optical data recording experiments have been carried out under 740 nm laser radiation, and the possible mechanism of optical data storage is discussed based on theoretical calculations.

Facile synthesis, optical properties and theoretical calculation of a novel bent-shaped two-photon absorption chromophore

A novel bent-shaped derivative, 2-thiomethyl-4,6-bis(4-N,N-methylaminostyryl) pyrimidine (TMAP) has been successfully synthesised and fully characterised by elemental analysis, IR, 1H NMR and MS. The molecule possesses D–π–A–π–D structures. Dimethylamino is used as the donor (D), and the pyrimidine ring is used as the acceptor (A). One- and two-photon absorption and fluorescence in various solvents were experimentally investigated. The chromophore shows intense single-photon excited fluorescence (SPEF) and two-photon excited fluorescence (TPEF) in a wide spectral range, with the spectral peak position of the SPEF being basically the same as that of the TPEF. The chromophore combines well with peak TPA cross-sections (up to 352.0 GM) and broad TPA bands throughout the whole 700–900 nm range and high-fluorescence quantum yields could thus be obtained. The theoretical and experimental studies indicate the charge transfer from donor to acceptor.

Cationic Two-Photon Absorption Chromophores with Double- and Triple-Bond Cores in Symmetric/Asymmetric Arrangements

Two-photon absorption (TPA) properties of a series of cationic, linear π-conjugated systems with donor(D)/acceptor(A) substitution have been examined systematically in terms of the type and length of the π-conjugation core and symmetric and asymmetric D/A-arrangement. The TPA spectra of the chromophores measured by the femtosecond open-aperture Z-scan method reveal that the double-bond core results in much more intense TPA than the triple-bond one, with a significant red shift of the TPA peak while the TPA becomes more intense as the chain is extended for the triple-bond core compounds with a little red shift. It is also found that the difference in the D/A-arrangement gives a small difference in the amplitude of the TPA spectrum although the spectral shapes differ considerably.

An effective surface-enhanced Raman scattering template based on a Ag nanocluster–ZnOnanowire array

An effective surface-enhanced Raman scattering (SERS) template based on a 3D hybrid Agnanocluster (NC)-decorated ZnO nanowire array was fabricated through a simple process ofdepositing Ag NCs on ZnO nanowire arrays. The effects of particle size and excitationenergy on the Raman scattering in these hybrid systems have been investigatedusing rhodamine 6G as a standard analyte. The results indicate that the hybridnanosystem with 150 nm Ag NCs produces a larger SERS enhancement factor of3.2 × 108, which is much higher than that of 10 nm Ag NCs(6.0 × 106) under 532 nm excitation energy. The hybrid nanowire arrays were further applied to obtainSERS spectra of the two-photon absorption (TPA) chromophore T7. Finite-differencetime-domain simulations reveal the presence of an enhanced field associated with inter-wireplasmon coupling of the 150 nm Ag NCs on adjacent ZnO nanowires; such a field wasabsent in the case of the 10 nm Ag NC-coated ZnO nanowire. Such hybrid nanosystemscould be used as SERS substrates more effectively than assembled Ag NC film due to theenhanced light-scattering local field and the inter-wire plasmon-enhanced electromagneticfield.

Synthesis, structure and nonlinear optical properties of two novel two-photon absorption chromophores

Two triphenylamine-based derivatives that can be used as two-photon absorption chromophore, tris{4-[4-(3-trifluoromethyl-3-oxopanoyl)]phenyl}amine (1) and tris{4-[4-(3-phenyl-3-oxopanoyl)] phenyl} amine (2) were successfully synthesized and fully characterized by elemental analysis, IR, 1H NMR and MS. The single crystal X-ray diffraction analysis showed that the molecules possess D-(π-A)3 structures. One-and two-photon absorption and fluorescence in various solvents were experimentally investigated. A data recording experiment proved the potential application of these chromophores.

Investigation of structure–property relationships of multi-branched two-photon absorption chromophores based on π-conjugation core

To investigate the effect of conjugated-core structure of multi-branched chromophore on linear and nonlinear optical properties, three novel multi-branched organic chromophores, 3-(3,5-bis(9-butyl-9H-carbazol-6-yl)phenyl)-6-(4-(2,6-diphenylpyidin-4-yl)styryl)-9-butyl-9H-carbazole (W1), 1-(9-butyl-9H-carbazol-6-yl) phenyl)-3,5-bis(3-(4-(2,6-diphenylpyidin-4-yl)styryl)-9-butyl-9H-carbazole-6-yl)benzene (W2) and 1,3,5-tri(3-(4-(2,6-diphenylpyidin-4-yl)styryl)-9-butyl-9H-carbazole-6-yl)benzene (W3) have been synthesized and characterized. Their linear absorption, one- and two-photon fluorescence properties have been investigated. All these chromophores show intense one-photon fluorescence and high fluorescence quantum yields. When exited by a Ti:sapphire laser, these chromophores exhibit strong two-photon-excited fluorescence. The two-photon absorption cross sections of W1, W2 and W3 were calculated to be 69 GM, 112 GM and 173 GM in DMF, respectively. The ratio of the three compounds from the experiment is 1:1.6:2.5. Structure-property relationships are discussed based on photophysical data and theoretical calculation, which indicate a linear enhancement in one- and two-photon absorption and emission in going from W1 via W2 to W3.

Synthesis and photophysical properties of novel pyrimidine-based two-photon absorption chromophores

Three new two-photon absorption chromophores based on a pyrimidine core were synthesized by Aldol condensation in the absence of any organic solvents. Their single-photon spectroscopic characterization as well as their two-photon absorption properties is reported. In addition, strong modulation of single-photon and two-photon fluorescent spectra of these molecules by (de)protonation is also discussed.

Synthesis, characterization and optical properties of a new heterocycle-based chromophore

A new heterocycle-based two-photon absorption chromophore, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)styryl]pyridine (DIYSP), has been synthesized and characterized. The molecule possesses an A–π–A′ structure. The π-deficient heteroaromatic ring (4,5-diphenyl-1H-imidazole) is used as an acceptor (A), and the pyridine ring is used as another acceptor (A′). Pumped with 740nm laser excitation, DIYSP had a two-photon absorption cross-section 41GM (1GM=1×10−50cm4sphoton−1) and a two-photon excited fluorescence 511nm in DMF, respectively. A microstructure using DIYSP as an initiator has been fabricated under irradiation of 80fs, 80MHz Ti:sapphire femtosecond laser at 800nm. The possible mechanism of photopolymerization is discussed.

Theoretical studies of nonlinear optical properties of a novel double-conjugated-segment molecule

One-photon and two-photon absorption properties of a double-conjugated-segment molecule (BSBAB) composed of two single-conjugated-segment molecules are studied by using density functional theory at ab initio level. The optimized geometrical structure shows that the two single-conjugated-segment parts in molecule BSBAB retain their own coplanarity and are nearly perpendicular to each other, which seems to indicate that the molecule BSBAB contains optical characteristics of both parts. The molecule BSBAB is found to have three two-photon absorption peaks in lowest energy region which are contributed respectively the two single-conjugated-segment parts respectively and the coupling between them. This also demonstrates that the molecule BSBAB is a broadband strong two-photon absorption chromophore. The response theory approach at Hatree-Fock level is used to prove the convergence of results given by the state summation method with truncated approximation. The charge-transfer process between the charge-transfer states is visualized. The theoretical results are in good agreement with the measurements.

Synthesis, Structures, and Two-Photon Absorption Properties of Two New Heterocycle-Based Organic Chromophores

Abstract Two new heterocycle-based two-photon absorption chromophores, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)styryl]pyridine (2) and (E)-4-{[2-(1H-benzimidazol-2-yl)vinyl]styryl}-N-methylpyridinium iodide (4), have been synthesized and characterized. The two molecules possess A–π–A′ structures. A π-deficient heteroaromatic ring (benzimidazole, 4,5-diphenyl-1H-imidazole) is used as an acceptor (A), and a pyridine ring is used as another acceptor (A′). One-photon-excited fluorescence, one-photon-fluorescence quantum yields, two-photon-excited fluorescence, and two-photon absorption cross-sections were investigated. Pumped with 740 and 800 nm laser excitation, compounds 2 and 4 had two-photon absorption cross-sections (41 and 38 GM) and two-photon-excited fluorescence (511 and 601 nm) in DMF, respectively. The crystal structure of compound 4 was determined by using X-ray single-crystal diffraction analysis.

Synthesis and two-photon absorption property of new π-conjugated dendritic fluorophores containing styrylpyridyl moieties

Four new multi-branched two-photon absorption chromophores, namely 1-(4-bromobenzal)-3,5-bis(4-(( E)-2-(pyridin-4-yl)vinyl)phenyl)benzene ( 4), tris(4-(( E)-2-(pyridin-4-yl)vinyl)phenyl)-benzene ( 5), 6-chloro- N 2, N 4-bis(4-(( E)-2-(pyridin-4-yl)vinyl)phenyl)-1,3,5-triazine-2,4-diamine ( 6), tris-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine ( 7), have been synthesized and characterized. One-photon fluorescence, fluorescent quantum yields and two-photon fluorescence have been investigated. The experimental two-photon absorption cross-sections of 4– 7 in DMF are 6, 11, 13 GM (pumped by 740 nm laser) and 19 GM (pumped by 800 nm laser), respectively. The calculated two-photon absorption cross-sections of 4– 7 are 5.41, 7.67, 9.57 and 76.14 GM, respectively. The two-photon induced fluorescent peak wavelengths of 4– 7 in DMF are 421, 425, 474 and 534 nm pumped by 680, 680, 740 and 800 nm laser, respectively. The results show that molecule 7 is a good two-photon absorption fluorophore possessing long two-photon fluorescent lifetime, good fluorescent quantum yield and large two-photon absorption cross-section. The two-photon absorption peak wavelength of molecule 7 is at 800 nm, which is favourable for initiating two-photon photopolymerization.

Two-photon absorption chromophores with a tunable [2,2′]bithiophene core

Sonogashira coupling between 3,5,3′,5′-tetrabromo-[2,2′]bithiophene and various terminal alkynes provides two-photon absorption (TPA) chromophores 1– 6, which possess electron donor (D) and/or acceptor (A) alkynyl substituents at 3(3′) and 5(5′) sites of the bithiophene core. The up-converted fluorescence emission excited at 800 nm (Ti:sapphire femtosecond laser, ∼100 fs pulses) was used to determine the two-photon absorption cross-sections ( σ) of these compounds. The corresponding TPA cross-section ( σ) values ranging from 132 to 1120 GM (10 −50 cm 4 s photon −1) can be fine-tuned by the substitutents. The quadrupolar-type (A-π-D-π-A) chromophore 5 exhibits the largest σ value (1120 GM) in CH 2Cl 2 upon 800 nm excitation.

Synthesis and Nonlinear Optical Properties of a New Two‐photon Polymerization Initiator: DPAMOB with a Large TPA Cross‐section

AbstractE,E‐1,4‐Bis(4′‐N,N‐diphenylaminostyryl)‐2,5‐dimethoxybenzene (DPAMOB) has been synthesized by a simple and effective solid phase Wittig reaction and characterized by 1H NMR spectra and elemental analysis. Linear absorption, single‐photon induced fluorescence and two‐photon induced fluorescence spectra were experimentally studied. The new dye has a large two‐photon absorption (TPA) cross‐section of σr=1007.2 GM [1 GM=1×10−50 cm4·s/(photon molecule)] at 800 nm measured by the two‐photon induced fluorescence method. The experimental results confirm that DPAMOB is a good TPA chromophore and can successfully initiate two‐photon photopolymerization of ethoxylated trimethylolpropane triacrylate esters (SR454). Finally, a microstructure has been fabricated by use of DPAMOB as initiator.

Synthesis and properties of a new two-photon absorbing chromophore

This paper presents of a new, conjugated and symmetric multi-branched two-photon absorption chromophore 1,2,4,5-tetrakis(4- N-methyl- N-hydroxyethylamino)vinylphenyl benzene (TKAVPB) with D-π-D structure. The new dye built on 1,2,4,5-benzene core with four amino-branching units, which allows efficient π-electron delocalization, exhibits moderate two-photon absorption (TPA) value in the femtoseconds regime (TPA cross-section as 97 × 10 −50 cm 4 s photon −1 molecule −1 with 200 fs laser pulses). Linear absorption, single and two-photon fluorescence spectra were experimentally studied. When pumped with 760 nm laser irradiation, TKAVPB shows strong two-photon up-conversion fluorescence with peak at 527 nm.

Synthesis and characterization of new fluorescent two-photon absorption chromophores

A series of dipolar and quadrupolar type two-photon absorption (TPA) compounds has been synthesized and TPA cross sections (σ) were measured by Ti∶sapphire femtosecond laser excitation fluorescence (λ = 800 nm). Among them, the compound [2,5-bis-[5-(4-diphenylaminophenylethynyl)thiophen-2-yl]-[1,3,4]oxadiazole], 12, has been structurally characterized by X-ray crystallography. The resulting data indicate that the structure of this compound possesses excellent coplanarity. The compounds have arylamines as the donor, and [1,3,4]oxadiazolyl, cyanovinyl or pyridazin-3,6-diyl moiety as the acceptor. Variation of arylamines and pendant alkyl groups was found to have a significant influence on σ values. By an appropriate combination of donor and acceptor, σ values of >103 GM (10−50 cm4s photon·molecule−1) can be achieved. One quadrupolar molecule (13) possessing an arylamine donor and a pyridazine acceptor has both a high σ value (1442 GM) and σ/MW (1.97 GM/g).

Synthesis and properties of new two-photon absorption chromophores containing 3,5-dicyano-2,4,6-tristyrylpyridine as the core

This paper reports the synthesis of a series of donor-substituted 3,5-dicyano-2,4,6-tristyrylpyridine derivatives, having two-dimensional branched D-π-A structures, as new two-photon absorption (TPA) chromophores. These chromophores are stilbene-type chromophores containing the same acceptor group but end-capped with different aromatic groups as the donors. Measured as the two-photon-induced fluorescence in chloroform solvent, using a femtosecond multipass Ti∶sapphire amplifier as the irradiation source, the TPA cross section values of some compounds are on the order of 10−48 cm4 s photon−1. These chromophores also have relatively high two-photon-excited fluorescence (TPEF) action cross sections. Pumped by the laser at 800 nm, these chromophores show efficient two-photon-induced orange-red fluorescence emission. The experimental results indicate that the different end-capped functional electronic donors and the number of branches of these chromophores affect their one-photon properties, two-photon up-conversion emission behavior and TPA cross section values. Especially, with increasing numbers of branches, λabsmax and λspfmax exhibit bathochromic shifts, while their two-photon absorption cross sections also increase. Compared with the two-branched chromophore 6, the tribranched chromophore 4 shows a larger TPA cross section, and the cooperative enhancement of the TPA cross section from 6 to 4 is 1.2-fold at 800 nm.

Synthesis and two-photon absorption properties of novel heterocycle-based organic molecules

Four novel heterocycle-based two-photon absorption chromophores were designed and synthesized. In these molecules, heterocyclic benzothiazole and oxadiazole derivatives are used as acceptors (A), and formyl group is another acceptor (A′) applied. These dyes have the structural motif of A–π–D–π–A or A–π–D–π–A′. All the chromophores show wide linear optical transparency and strong single-photon and two-photon excited emission. The two-photon absorption cross-sections of molecules with A–π–D–π–A backbone with two heterocycle-based acceptors are as large as 521 GM and 461 GM at the wavelength of 788 nm in the femtosecond regime. The molecules of A–π–D–π–A′ framework show relatively low two-photon absorbing activities due to the small π-conjugation systems.

Synthesis, nonlinear optical properties and the possible mechanism of photopolymerization of two new two-photon absorption chromophores

Efficient Witting and Pd-catalyzed Heck coupling methodologies are employed to synthesize two new two-photon free-radical photopolymerization initiators 9-ethyl-3-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-9H-carbazole (abbreviated to EPVPC) and 9-octadecyl-3-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-9H-carbazole (abbreviated to OPVPC). The experimental results confirm that the two compounds are good two-photon absorbing chromophores and operative two-photon photopolymerization initiators. The calculated two-photon absorption cross-sections of EPVPC and OPVPC are 56.6 and 62.0×10 −50 cm 4 s photon −1, respectively. A microstructure by using EPVPC as initiator has been fabricated under irradiation of 200 fs, 76 MHz Ti:sapphire femtosecond laser at 780 nm. The possible mechanism of photopolymerization is discussed.

Two-photon fluorescence properties of a styrylpyridinium derivative organic chromophore in different solvents

The fluorescence properties of a new two-photon absorption chromophore in dimethyl formamide, methanol, acetone, benzyl alcohol, methylene chloride and chloroform are reported. The lifetime, intensity and central wavelength of the fluorescence signal vary significantly in different solvents. The fluorescence properties are explained by using the twisted intra-molecular charge-transfer model, the viscosity of the solvents and the formation of the hydrogen bond. For the dye in all solvents, the longer the fluorescence lifetime, the higher the fluorescence intensity. Generally, the higher the dipole moments, the longer the central wavelengths of the dye.

Lithographic Microfabrication by Using Two-Photon Absorbing Phenylenevinylene Derivative

The phenylenevinylene-based two-photon absorbing chromophore(EA4BPA-VB)with a triphenyl amine as an electron donor was synthesized. The two-photon absorption(TPA)cross-section values of EA4BPA-VB measured by two-photon-induced fluorescence method with 80 fs-pulse laser were found to beσ2 = 4.7 × 10−48 cm4s/photon. By adding this chromophore into photo-reactive SCR resin, we have successfully fabricated 3-D micro-structure(a larva)with high spatial resolution at low laser power with less than 5 mW. To improve the resolution of 3-D patternings, we also investigated a voxel size and shape depending on laser exposure time and concentration of TPA chromophore in SCR resin at near-threshold exposure condition.