Highly sensitive two-photon chromophores applied to three-dimensional lithographic microfabrication: design, synthesis and characterization towards two-photon absorption cross section

Abstract

A series of D-p-A-p-D type chromophores were synthesized by the dehydration reaction of 4-R 2 Nbenzaldehye (R ~Ph, Bu n , Et, Me) and diaminomaleonitrile (corresponding to the chromophores 1, 2, 3 and 4, respectively), in which a polar imino double bond (-CLN-) replaced the double bond (-CHLCH-) in the p-conjugated centers. Femtosecond laser induced fluorescence intensity was used to evaluate two-photon absorption (TPA) cross sections, d, using a USB-2000 CCD. Results show a change of terminal groups from Ph 2 N-to Me 2 N-influenced the d value significantly through a change of the quantum yield, Q. However, the two-photon absorption peak position was only slightly affected. The chromophores 2 and 3 were found to afford polymers in the presence of the functional triacrylate monomer at low laser power at 755 and 820 nm. This demonstrated that the enhanced d value was not a main factor in the improvement of chromophore twophoton photosensitivity. Such information can be useful in the design of more efficient two-photon chromophores for imaging and power-limiting applications.Experimental 1. Chemicals Diaminomaleonitrile (98%) and 4-diphenyl-or 4-dialkyl-aminobenzaldehydes (98%) were purchased from Aldrich. The solvents

Precise Molecular Design for High‐Performance Luminogens with Aggregation‐Induced Emission

“…In this manner, the shape and rigidity of acceptor are strongly associated with the conformation of the CT state, which is crucial to the energy gap. For example, by fusing the pyrazine ring, the enhanced molecular rigidity led to red‐shifted emission from 616 nm for 31 to 632 nm for 32 ( Figure ) . From 32 to 33 , by introducing the fused ring structure of dibenzoquinoxaline‐2,3‐dicarbonitrile (DCPP), the CT state of 33 is enhanced as compared to 32 , leading to a significant red‐shift of 75 nm in emission .…”

One step synthesis of D-A-D chromophores as active materials for organic solar cells by basic condensation

“…Some recent works have demonstrated the possibility of synthesizing D-A or D-A-D systems by means of more environmental friendly methods such as click chemistry [5] or basic condensations [6]. Additionally, the two-fold condensation of aromatic aldehydes onto commercial (Z)-2,3-diaminomaleonitrile to form D-A-D compounds with a central diiminofumaronitrile electro-deficient group has been scantly studied and most articles have been focused on the optical [7] or aggregative [8] properties of the compounds. A first report on the use of N,N-bis [4-(N,N-diethylamino)benzylidene]diaminomaleonitrile as active material in a Schottky solar cell has been published some years ago leading to a PCE of 0.38% under low intensity illumination [9].…”

Two‐Photon Polymerization of Biocompatible Photopolymers for Microstructured 3D Biointerfaces

“…[73,74] One of the most serious drawbacks of the 2PP technology is the inherent serial, voxel-by-voxel character of the fabrication process resulting in extended processing times. Thus, various scaling-up strategies have been established in recent years: application of specially designed two-photon absorbers that exhibit large two-photon absorption cross-sections, [75][76][77][78][79][80][81] multibeam interference lithography, [82] holographic techniques, parallel processing using individually controlled multilaser processing, [83] functional patterning within preformed hydrogels, [84,85] ''prechirp'' pulse shaping, [86] the use of alternative laser sources, [87] and volume solidification using UV-irradiation after the outer shell of the structure is formed by femtosecond pulses. [33] We report here on the synthesis and characterization, the 2PP processability and the cytocompatibility of a set of photopolymers for scaffold microfabrication including our strategy to build large-volume scaffolds for 3D culture of bovine chondrocytes.…”