Enhancement of two-photon initiation efficiency based on conjugated phenothiazine and carbazole derivatives

Li, Shanggeng; Lu, Chengjia; Wan, Xiangyu; Zhang, Shuai; Li, Jing; He, Zhibing; Zhang, Lin

doi:10.1016/j.mtcomm.2020.101219

Cited by 14 publications

(7 citation statements)

References 39 publications

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“…To investigate the influence of the core structure, Li et al. synthesized four different photo initiators, two with a carbazole core and two with a phenothiazine core [174] . In addition, the structures of the initiators showed two different acceptor groups, a thiophen aldehyde and quinoline group, which are linked to the core via triple bond bridges (Figure 89).…”

Section: A‐π‐d‐π‐a and D‐π‐d‐π‐d Chromophoresmentioning

confidence: 99%

From Light to Structure: Photo Initiators for Radical Two‐Photon Polymerization

Schubert

Wloka

Gottschaldt

2022

Chemistry A European J

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Two-photon polymerization (2PP) represents a powerful technique for the fabrication of precise threedimensional structures on a micro-and nanometer scale for various applications. While many review articles are focusing on the used polymeric materials and their application in 2PP, in this review the class of two-photon photo initiators (2PI) used for radical polymerization is discussed in detail. Because the demand for highly efficient 2PI has increased in the last decades, different approaches in designing new efficient 2PIs occurred. This review summarizes the 2PIs known in literature and discusses their absorption behavior under one-and twophoton absorption (2PA) conditions, their two-photon cross sections (σ TPA ) as well as their efficiency under 2PP conditions. Here, the photo initiators are grouped depending on their chromophore system (D-π-A-π-D, D-π-D, etc.). Their polymerization efficiencies are evaluated by fabrication windows (FW) depending on different laser intensities and writing speeds.

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Section: A‐π‐d‐π‐a and D‐π‐d‐π‐d Chromophoresmentioning

confidence: 99%

From Light to Structure: Photo Initiators for Radical Two‐Photon Polymerization

Schubert

Wloka

Gottschaldt

2022

Chemistry A European J

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“…50 However, many research groups that assess the effectiveness of PIs by determining TPA cross sections using high-repetition rate (as e.g., MHz) femtosecond (fs) laser sources have led to the erroneous conclusion that a high cross section does not responsible for high efficiency. [51][52][53][54] Primarily under such experimental conditions, unwanted thermal effects inevitably manifest, obscuring pure electronic response contributions to the NLO response. 55 As a result, erroneous extremely large values of TPA cross section have been reported.…”

Section: Introductionmentioning

confidence: 99%

Push-Pull Carbazole-Based Dyes: Synthesis, Strong Ultrafast Nonlinear Optical Response, and Effective Photoinitiation for Multiphoton Lithography

Stavrou,

Zyla,

Ladika

et al. 2024

Preprint

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The present work reports on the ultrafast nonlinear optical (NLO) properties of a series of D-π-Α and D-A push-pull carbazole-based dyes and establishes a correlation between these properties and their efficiency for potential photonic and optoelectronic applications, such as multiphoton lithography (MPL). The ultrafast NLO properties of the studied dyes are determined by two distinct experimental techniques, Z-scan and pump-probe optical Kerr effect (OKE), employing 246 fs laser pulses at 515 nm. The results indicate that chemical functionalization of the carbazole moiety with various strong electron-donating and/or electron-withdrawing groups, such as benzene, styrene, 4-bromostyrene, nitrobenzene, trimethyl isocyanurate, methyl, and indane-1,3-dione, can result in a controlled and significant enhancement of the NLO absorptive and refractive responses. In the context of potential applications, the efficiency of carbazole-based organic materials as photoinitiators (PIs) for MPL applications is demonstrated. The fabricated woodpile microstructure using chemically functionalized carbazole as a PI demonstrates improvements in both resolution and MPL efficiency compared to that using unfunctionalized carbazole as a PI. This attributed to efficient charge transfer resulting from chemical functionalization, which leads to a substantial increase (approximately one order of magnitude) in the values of the imaginary part of the second-order hyperpolarizability (Imγ) and the two-photon absorption cross section (σ). The achieved resolution of 280 nm is comparable to that obtained with other widely used PIs in MPL applications. Additionally, owing to strong NLO refraction and Kerr signal of the studied functionalized carbazole, they also exhibit promise as candidates for all-optical switching applications in telecommunications, optical computing, data processing, etc.

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“…Efforts made through the years to mitigate, or to suppress these differences, have followed two main perimeters of action: i) optimizing the chemical properties of the photoresists, ii) circumventing the physical limitations of the optical system employed for the polymerization. As an example of recent works on the optimization of the photoresist's chemical properties, Zhang and collaborators proposed a high-efficiency photoinitiator with a conjugated A-π-D-π-A structure of phenothiazine and carbazole derivatives, [16] achieving a writing speed of 14 mm s −1 , while Li and coworkers showed the synthesis of a series of π-extended benzophenone photoinitiators, [17] which allowed to reach a writing speed of 100 mm s −1 . Liao et al [18] and Spadaccini et al [19] have provided comprehensive reviews on materials and challenges for developing the next generation of TPL photoresists.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances on High‐Speed and Holographic Two‐Photon Direct Laser Writing

Balena

Bianco

Pisanello

et al. 2023

Adv Funct Materials

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Two‐Photon Lithography, thanks to its very high sub‐diffraction resolution, has become the lithographic technique par excellence in applications requiring small feature sizes and complex 3D pattering. Despite this, the fabrication times required for extended structures remain much longer than those of other competing techniques (UV mask lithography, nanoimprinting, etc.). Its low throughput prevents its wide adoption in industrial applications. To increase it, over the years different solutions have been proposed, although their usage is difficult to generalize and may be limited depending on the specific application. A promising strategy to further increase the throughput of Two‐Photon Lithography, opening a concrete window for its adoption in industry, lies in its combination with holography approaches: in this way it is possible to generate dozens of foci from a single laser beam, thus parallelizing the fabrication of periodic structures, or to engineer the intensity distribution on the writing plane in a complex way, obtaining 3D microstructures with a single exposure. Here, the fundamental concepts behind high‐speed Two‐Photon Lithography and its combination with holography are discussed, and the literary production of recent years that exploits such techniques is reviewed, and contextualized according to the topic covered.

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Enhancement of two-photon initiation efficiency based on conjugated phenothiazine and carbazole derivatives

Cited by 14 publications

References 39 publications

From Light to Structure: Photo Initiators for Radical Two‐Photon Polymerization

From Light to Structure: Photo Initiators for Radical Two‐Photon Polymerization

Push-Pull Carbazole-Based Dyes: Synthesis, Strong Ultrafast Nonlinear Optical Response, and Effective Photoinitiation for Multiphoton Lithography

Recent Advances on High‐Speed and Holographic Two‐Photon Direct Laser Writing

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