Enhanced performance of photorefractive poly(<i>N</i>‐vinyl carbazole) composites

Tsutsumi, Naoto; Dohi, Akihito; Nonomura, Asato; Sakai, Wataru

doi:10.1002/polb.22203

Cited by 12 publications

(12 citation statements)

References 17 publications

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“…The values of trap density can be estimated by Kukhtarev model which was described in the previous papers. [10,23,24] Table 3 shows the values of the trap-limitted space-charge field E q and number density of traps N t . As can be observed, the values of E q and trap density in the PDAA-based composites are The PMPAA's HOMO level is higher than that of all the other components whereas the PDAA's HOMO level is lower than that of the plasticizer TPAOH.…”

Section: Resultsmentioning

confidence: 99%

“…Values of phase shift were calculated by coupled-wave theory from the values of diffraction efficiency and optical gain. [10,24,25] The results of optical gain, absorption coefficient and phase shift values are summarized in Table 1 and 2. The performance of optical gain follows the same tendency to the diffraction efficiency results.…”

Section: Resultsmentioning

confidence: 99%

“…[9] To make the composite less inert, the photoconductive plasticizer ethyl carbazole (ECZ) is widely used with PVK and even with bistriarylamine polymer. [10][11][12][13][14][15][16] Recently, photoconductive polymers based on triphenylamine have been utilized for fast response PR application because of their fast hole mobility. A vinyl type of triphenylamine polymer, poly((4-diphenylamino)styrene) (PDAS), for PR composite has been reported.…”

Section: Introductionmentioning

confidence: 99%

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Triphenylamine photoconductive polymers for high performance photorefractive devices

Giang

Kinashi

Sakai

et al. 2014

Journal of Photochemistry and Photobiology A: Chemistry

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Photorefractive performances of the composites using two kinds of photoconductive triphenylamine-based polymer have been compared and investigated. One polymer is poly(4-(diphenylamino)benzyl acrylate) (PDAA). The other is newly synthesized one of photoconductive acrylate polymer with methoxy substituted triphenylamine pendant, poly(4-((4methoxyphenyl)(phenyl)amino)benzyl acrylate) (PMPAA). The methoxy substituent in PMPAA does not only shift the highest occupied molecular orbital (HOMO) level of the polymer, but also effectively enhances the chromophore orientation. Larger phase shift is confirmed by using the modified photoconductive polymer of PMPAA. The plasticizer of (4-(diphenylamino)phenyl)methanol (TPAOH) (IP = − 5.64 eV) works as an effective trap in the PDAA (IP= − 5.69 eV)based composite, resulting in higher diffraction efficiency. Diffraction efficiency of 70 % and fast response time of 25 ms (dominant) is measured at 532 nm under the moderate electric field of 45 V/µm.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Triphenylamine photoconductive polymers for high performance photorefractive devices

Giang

Kinashi

Sakai

et al. 2014

Journal of Photochemistry and Photobiology A: Chemistry

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“…51 A polyacrylate PR composite with carbazole as a pendant group was designed, and its PR performance was found to be almost identical to a PVK-based PR composite. 52 A PR molecular glass of a multifunctional conjugated carbazole trimer ( Figure 2) was also designed, and an optical gain of 35.0 cm −1 (net gain of 26.8 cm −1 ) was recorded under E = 33 V μm − 1 at 532 nm.…”

Section: Photoconductive Polymersmentioning

confidence: 99%

Molecular design of photorefractive polymers

Tsutsumi

2016

Polym J

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This review article describes the current state-of-the-art research on organic photorefractive polymer composites. A historical background on photorefractive materials is first introduced and is followed by a discussion on the opto-physical aspects and the mechanism of photorefractivity. The molecular design of photorefractive polymers and organic compounds is discussed, followed by a discussion on optical applications of the photorefractive polymers. Polymer Journal (2016) 48, 571-588; doi:10.1038/pj.2015.131; published online 27 January 2016 BACKGROUND In this report, the molecular design of organic photorefractive (PR) polymers is reviewed. Organic PR polymers are materials that possess both electro-optical and photoconductive properties. Research on photoconductive polymers, whose pioneering polymer is poly(N-vinyl carbazole) (PVK, PVCz), began in the 1960s. From the 1980s, research on organic nonlinear optical (NLO) materials has been widely conducted in the fields of organic electro-optics and optical nonlinearity. From the 1990s, new technology using organic photorefractivity combined with photoconductive and electro-optical properties was introduced in the field of organic semiconducting materials, 1 and organic light-emitting diodes 2-6 and organic fieldeffect transistors 7 were also debuted in this field. At the same time, the interest of researchers also turned toward the development of organic photovoltaic cells and organic solar cells. [8][9][10][11] The transport of charge carriers through photoconductive manifolds is a common phenomenon found in PR, organic light-emitting diode or organic photovoltaic materials. Thus, the development of materials in each field is expected to merge together to trigger the development of novel materials.The PR effect is a well-known phenomenon that is observed in materials in which refractive index modulation is induced by the space-charge field that results from the redistribution of positive and negative charge carriers separated through photo-excitation. 12 This phenomenon was first reported in inorganic crystals of lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ) and was observed through heterogeneous optically induced refractive indices in 1966. 13 Since then, the PR effect has extensively been investigated in many inorganic crystals, and theoretical approaches have been established to explain this phenomenon. 14 In 1991, 1 the first study of PR polymers reported a low diffraction efficiency of 10 −3 to 1% and a small optical gain of 0.33 cm À1 . In 1994, 15 a high diffraction efficiency of 86% (the remaining 14% was attributed to optical losses) and a large optical gain exceeding 200 cm À1 was reported in photoconductive PVK-based PR composites. Over the past two decades, many featured review articles [16][17][18][19][20][21][22][23][24][25][26][27] and book

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“…It is of interest to investigate how the cooperative reaction depends on the molecular form of the reactants, not only in enzyme reactions but also in general organic reactions (3,4). We have investigated the relationship between the molecular form and the reactivity in the ester hydrolytic reactions using linear, 269 cyclic and polymeric peptides containing His, mational investigations by CD are presented Ser and Asp residues (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), which are the key and are discussed in comparison with the amino acids in serine proteases. The three results in the kinetic work.…”

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confidence: 99%

Circular dichroism investigations on the conformation of linear, cyclic and polymeric peptides containing His, Ser and Asp residues

Nishi

Nakajima

Yoneyama

et al. 1986

International Journal of Peptide and Protein Research

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Conformational studies on the linear, cyclic and polymeric peptides with the sequences ‐Asp‐ßAla‐Gly‐Ser‐ßAla‐Gly‐His‐ßAla‐Gly‐(nonapeptide series) and ‐Asp‐eAhx‐Ser‐eAhx‐His‐eAhx (hexapeptide series) were carried out by means of circular dichroism measurements to clarify the relationship between their conformation and ester hydrolytic activity. It was suggested that all of the present peptides take a certain ordered conformation at acidic pH region and have a tendency to transform to a disordered conformation with a rise of pH. In the course of the conformational change, the linear and polymeric peptides undergo a drastic conformational change at around pH 7.0, while the cyclic peptides maintain the ordered conformation to some extent even at the basic pH region. Although this ordered conformation maintained in the cyclic peptides was estimated not to be a tight one, it was more stable in the cyclic peptide of the latter sequence (Cyclic‐6) than in the former sequence (Cyclic‐9). As reported previously, Cyclic‐6 showed greater activity than the others in the hydrolysis of various ester substrates. Higher activity and more stable ordered conformation of Cyclic‐6 seem to be closely related. The effects of urea, organic solvent, salt and change of temperature on their conformation are also reported.

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Enhanced performance of photorefractive poly(N‐vinyl carbazole) composites

Cited by 12 publications

References 17 publications

Triphenylamine photoconductive polymers for high performance photorefractive devices

Triphenylamine photoconductive polymers for high performance photorefractive devices

Molecular design of photorefractive polymers

Circular dichroism investigations on the conformation of linear, cyclic and polymeric peptides containing His, Ser and Asp residues

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