論文 - パンディ　シャム　スディル

Synthesis and Characterization of Newly Designed and Highly Solvatochromic Double Squaraine Dye for Sensitive and Selective Recognition towards Cu2+ 査読有り

Linjun Tang, Shubham Sharma, Shyam S Pandey

Molecules ( MDPI )   27 ( 19 )   6578   2022年10月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Synthesis and characterization of a novel and zwitterionic double squaraine dye (DSQ) with a unique D-A-A-D structure is being reported. Contrary to the conventional mono and bis-squaraine dyes with D-A-D and D-A-D-A molecular frameworks reported so far, DSQ dye demonstrated strong solvatochromism allowing for the multiple ion sensing using a single probe by judicious selection of the suitable solvent system. The DSQ dye exhibited a large solvatochromic shift of about 200 nm with color changes from the visible to NIR region with metal ion sensitivity. Utilization of a binary solvent consisted of dimethylformamide and acetonitrile (1:99, v/v), highly selective detection of Cu2+ ions with the linearity range from 50 μM to 1 nM and a detection limit of 6.5 × 10−10 M has been successfully demonstrated. Results of the Benesi–Hildebrand and Jobs plot analysis revealed that DSQ and Cu2+ ions interact in the 2:1 molecular stoichiometry with appreciably good association constant of 2.32 × 104 M−1. Considering the allowed limit of Cu2+ ions intake by human body as recommended by WHO to be 30 μM, the proposed dye can be conveniently used for the simple and naked eye colorimetric monitoring of the drinking water quality.

DOI： https://doi.org/10.3390/molecules27196578

DOI： https://doi.org/10.3390/molecules27196578

その他リンク： https://www.mdpi.com/1420-3049/27/19/6578

Electronic versus Ionic Electroactive Polymers (EAPs) Strain Sensors for Wearable Electronics: A Comparative Study 査読有り

Nitin Kumar Singh, Kazuto Takashima, Shyam Sudhir Pandey

Engineering Proceedings ( Multidisciplinary Digital Publishing Institute )   21 ( 1 )   2022年08月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Electroactive polymer (EAP) strain sensors have gained appreciable attention as a potential candidate for their application in the area of soft electromechanical devices and have been widely used in soft robotics, healthcare, augmented reality, and wearable devices. In this research, a systematic comparison has been made by fabricating the electronic and ionic types of capacitive EAP strain sensors. To accomplish this, a combination of silicone rubber sandwiched between silver-coated stretchable fabric electrodes is used as an electronic type of EAP sensor, while a conducting and stretchable freestanding film consisting of Styrene-ethylene-butylene-styrene (SEBS) rubber and dedocyl benzene sulfonate acid (DBSA) doped polyaniline composite film sandwiched between carbon grease electrodes is chosen as an ionic type of EAP sensor. Mechanical characterization in terms of the uniaxial tensile testing was …

DOI： https://doi.org/10.3390/engproc2022021001

DOI： https://doi.org/10.3390/engproc2022021001

その他リンク： https://www.mdpi.com/2673-4591/21/1/1

Fabrication, characterization and modelling of the fabric electrode-based highly stretchable capacitive strain sensor 査読有り

Nitin Kumar Singh, Kazuto Takashima, Shyam S Pandey

Materials Today Communications ( Elsevier )   32   104095   2022年07月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Highly stretchable and capacitance-based strain sensors were fabricated utilizing highly stretchable silicone elastomer as dielectric film sandwiched between the conducting and stretchable cloth-based top and bottom electrodes. Electromechanical characterizations for the proposed sensor after multiple and reversible loading and unloading cycles up to 150% applied strain were conducted followed by the modelling of the sensing performance. It has been shown that the sensor exhibits reproducible electromechanical performance under multiple reversible stretching and relaxation cycles. There was a very small deviation (< 10%) in the observed values of the capacitance upon the applied strain of 150% up to the 1000 loading and unloading cycles. Tensile measurement for the sensor under various applied strains, not only exhibits almost constant force indicating negligible Mullins effect and negligible time-dependent changes at a fixed strain up to 100% suggesting that viscoelastic losses can also be neglected. From uniaxial tensile experiments, constitutive model of the dielectric elastomer sensor was validated. For the fitting of the experimental data obtained from the uniaxial tensile measurement, a variety of strain energy formulations have been compared for predicting the constitutive behaviour of sensor using the Mooney– Rivlin, Neo-Hookean, Yeoh and Ogden models, where 2nd term of the Ogden model was found to explain the experimental tensile data most accurately. To explain some observed losses at 150% of applied strain, the Prony series-based time dependent model was used for predicting stress at any value of time and it was found that experimental data was well fit with 4th order of Prony series.

DOI： https://doi.org/10.1016/j.mtcomm.2022.104095

DOI： https://doi.org/10.1016/j.mtcomm.2022.104095

その他リンク： https://www.sciencedirect.com/science/article/pii/S2352492822009473

Fabrication and Characterization of Oriented Thin Films of DPP-based Conjugated Copolymer Prepared by Friction Transfer Method 査読有り

Yuki Kurokawa, Ajendra K Vats, Shuichi Nagarnatsu, Shyam S Pandey

IEEE Explore ( IEEE )   124 - 127   2022年07月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   http://www.amfpd.jp/   2022年07月05日  -  2022年07月08日

DOI： 10.23919/AM-FPD54920.2022.9851297

DOI： 10.23919/AM-FPD54920.2022.9851297

その他リンク： http://www.amfpd.jp/

Interplay of viscosities in controlling the orientation of conjugated polymer thin films fabricated by floating film transfer method 査読有り

Shubham Sharma, Ajendra K Vats, Shuichi Nagamatsu, Shyam S Pandey

IEEE Explore ( IEEE )   116 - 119   2022年07月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   http://www.amfpd.jp/   2022年07月05日  -  2022年07月08日

DOI： 10.23919/AM-FPD54920.2022.9851340

DOI： 10.23919/AM-FPD54920.2022.9851340

その他リンク： http://www.amfpd.jp/

Tear strength estimation of electroactive polymer-based strain sensors 査読有り

Nitin Kumar Singh, Kazuto Takashima, Shyam Sudhir Pandey

Electroactive Polymer Actuators and Devices (EAPAD) XXIIV ( SPIE )   12042   424 - 428   2022年04月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

USA   https://www.spiedigitallibrary.org/conference-proceedings-of-spie/12042/1204217/Tear-strength-estimation-of-electroactive-polymer-based-strain-sensors/10.1117/12.2627807.short  

Electroactive polymer-based sensors are subjected to repeated loading and unloading cycles under variable applied strains and estimation of the tear strength plays a critical role in determining durability. A trouser type of specimen made from conducting and stretchable freestanding films consisting of SEBS rubber and dodecyl benzenesulfonic acid (DBSA) doped polyaniline composite was used for fabricating the capacitive strain sensor and tear strength estimation. Strain energy density for the composite film was calculated from the tear test data aiming towards the prediction of the life of the specimen. Our results revealed a very high value (150 newton/mm) of tear strength, leading to the sustainability of the film up to millions of cycles.

DOI： https://doi.org/10.1117/12.2627807

DOI： https://doi.org/10.1117/12.2627807

その他リンク： https://www.spiedigitallibrary.org/conference-proceedings-of-spie/12042/1204217/Tear-strength-estimation-of-electroactive-polymer-based-strain-sensors/10.1117/12.2627807.short

Computational molecular design of NIR dyes with varying anchoring groups for improving the efficiency and stability of dye-sensitized solar cells 査読有り 国際誌

Pandey S.S., Vats A.K., Tang L., Hayase S.

Japanese Journal of Applied Physics   61 ( SB )   SB1021-1 - SB1021-11-   2022年01月

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Design and development of near-infrared (NIR) dyes with strong binding on the TiO2 surface is inevitable for the realization of the dye-sensitized solar cells (DSSCs) with improved efficiency and stability. A series of NIR dyes bearing different anchoring groups have been designed considering their suitability as sensitizers for DSSCs based-on TiO2 and iodine-based redox electrolytes. Under the Gaussian program, density functional theory (DFT)/6-311G/B3PW91 level of theory and time-dependent-DFT using the polarizable continuum model is shown optimum for the prediction of the highest occupied molecular orbital energy level and electronic absorption spectra. The reliability of the calculated results was validated by corresponding experimental results for some of the representative dyes. It has been demonstrated that λ max at full width at half maximum in calculated absorption spectra exhibited an excellent match with the experimentally estimated Eg of the sensitizers leading to the proposal of a new method for the construction of the theoretical energy band diagram. Amongst newly designed sensitizers, dyes bearing dual anchoring groups like SQ-149, SQ-150, SQ-158, SQ-161 and SQ-162 are highly promising not only for good NIR photon harvesting but also to impart to improved DSSC stability.

DOI： 10.35848/1347-4065/ac28e8

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85125598296&origin=inward

Charge transfer and catalytic properties of various PEDOTs as Pt-free counter electrodes for dye-sensitized solar cells 査読有り 国際誌

Yuki Kurokawa, Ajendra Kumar Vats, Takehito Kato, Suhaidi Shafie, Shyam S. Pandey

Japanese Journal of Applied Physics   61 ( SB )   SB1010-1 - SB10110-6   2022年01月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Despite the high electrocatalytic activity of Pt and the fact it is a champion catalyst for the counter electrode (CE) of state-of-art dye-sensitized solar
cells (DSSCs), its high cost, rarity, and the concern about its possible deterioration by the iodine-based redox electrolyte, has compelled the search
for suitable and low-cost catalysts for CEs. To circumvent this issue, efforts were directed to exploring the suitability of various types of poly(3,4-
ethylenedioxythiophene)(PEDOT)-based conducting polymers as the most suitable electrocatalysts for low-cost CEs. Amongst various types of
PEDOT explored as CEs, micelle directed electropolymerized PEDOT:SDS (:sodium dodecyl sulfate) exhibited not only excellent catalytic activity
(>Pt), as confirmed by cyclic voltammetry and electrical impedance spectroscopy investigations, but also fairly good photovoltaic performance
exhibiting photoconversion efficiency of 5.8%, which is only slightly lower than the performance shown by Pt-based CE for the DSSCs fabricated
under similar experimental conditions. Further improvement for the PEDOT:SDS-based CE surpassing the Pt-based CE is envisioned by
morphological control and making their suitable composites with carbon-based nanomaterials.

DOI： https://doi.org/10.35848/1347-4065/ac2cf8

DOI： https://doi.org/10.35848/1347-4065/ac2cf8

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac2cf8

Bifacial dye-sensitized solar cells utilizing green colored NIR sensitive unsymmetrical squaraine dye 査読有り 国際誌

Suraya Shaban, Pritha Roy, Ajendra K. Vats and Shyam S. Pandeyy

Japanese Journal of Applied Physics   61 ( SB )   SB1005-1 - SB1005-6   2022年01月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Dye-sensitized solar cells (DSSCs) with the capability of photon harvesting from both front and rear sides, consisting of newly developed NIR dye
(SQ-140), iodine-based redox electrolyte, and transparent counter electrode with high bifaciality factor (BFF) and good cumulated photoconversion
efficiency (PCE), are successfully fabricated and characterized. The use of transparent TiO2-based photoanode leads to improved BFF as
compared to its opaque TiO2 counterparts: from 74% to 86% under similar experimental conditions and device parameters. The high molar
extinction coefficient of the NIR dye SQ-140, needing a thinner TiO2 layer, was found to be advantageous to maintaining the high BFF even in
thicker TiO2 films without serious compromise in the PCE. The lower efficiency of the bifacial DSSC under rear illumination was attributed to the
hampered optical penetration as well as absorption of light by the intense colored iodine-based redox electrolyte.

DOI： https://doi.org/10.35848/1347-4065/ac3570

DOI： https://doi.org/10.35848/1347-4065/ac3570

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac3570

Recent progress in the macroscopic orientation of semiconducting polymers by floating film transfer method, 査読有り 国際誌

Manish Pandey, Vipul Singh, Chandan Kumar, Shyam S. Pandey, and Masakazu Nakamura

Japanese Journal of Applied Physics   61 ( SB )   SB0801-1 - SB0801-12   2022年01月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Orienting semiconducting polymers (SCPs) using solution-processable techniques for organic electronic devices is essential for realizing a
printable electronics device. Preparation of oriented films on liquid substrates and transferring on actual device substrate offers many advantages,
including layer-by-layer coating, independent control of morphology, freedom to choose substrates, and device geometry. The floating films transfer
method (FTM) has emerged as a unique method to prepare oriented films of SCP using solution processing. Here, we review recent progress in
this method from the viewpoint of improvement in FTM to orient SCPs and their anisotropy in organic field effect transistors. In addition, the use of
FTM films in sensing applications is also reviewed.

DOI： https://doi.org/10.35848/1347-4065/ac2f20

DOI： https://doi.org/10.35848/1347-4065/ac2f20

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac2f20

A COMPARATIVE STUDY OF GRAPHENATED-CARBON NANOTUBES COTTON AND CARBON NANOTUBES AS CATALYSTS FOR COUNTER ELECTRODE IN DYE-SENSITIZED SOLAR CELLS 査読有り 国際誌

Yusnita Yusuf, Suhaidi Shafie, Ismayadi Ismail, Fauzan Ahmad, Mohd Nizar Hamidon, Shyam S Pandey, Nazalea Yazmin Muhammad, Wei Lei

Malaysian Journal of Microscopy   2021年12月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

This work reports a comparative study of synthesized graphenated-carbon nanotubes cotton (g-CNTC), standard carbon nanotubes (CNTP), and conventional platinum (Pt) thin layer which are employed as the counter electrodes in dye-sensitized solar cells (DSSC). The g-CNTC was synthesized via the floating-catalyst chemical vapor deposition (FCCVD) method. Subsequently, the g-CNTC was made into a uniform paste and deposited for the counter electrode layer. The results obtained from FESEM/TEM, Raman spectroscopy, CV and I-V measurements respectively exposed the structural, graphitization and I-V characteristics. Briefly, the morphology of g-CNTC showed the growth of graphene foliates out-sidewalls of CNT with a diameter of 40 nm. The graphitization of g-CNTC showed two dominant peaks namely the D (1355 cm-1) and G (1608 cm-1) bands with strong intensities. The g-CNTC counter electrode provided good electrical conductivity (3.66×10-3 to 6.45×10-3 S/cm), which is a significant feature to employ counter electrodes to enhance DSSC performance. In addition, the g-CNTC counter electrode offered an excellent catalytic activity for iodide/triiodide reaction and exhibited 3.49 % of photovoltaic conversion energy, which was much higher compared to CNTP (2.93 %) and platinum (3.12 %), respectively.

その他リンク： https://malaysianjournalofmicroscopy.org/ojs/index.php/mjm/index

Highly sensitive organic phototransistors fabricated from PCPDTBT: PCBM blend 査読有り 国際誌

Yadav N., Kumari N., Ando Y., Pandey S.S., Singh V.

Journal of Physics: Conference Series   2070 ( 1 )   2021年11月

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Organic phototransistors (OPTs) play a crucial role in various light sensing and imaging applications. In this work, we have fabricated highly sensitive Poly[2,6-(4,4-bis-(2ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blended thin film based OPTs using ribbon-floating film transfer method. A high charge carrier mobility (µ) of 0.002 cm2V-1s-1 and an Ion/Ioff of 6 × 104 was showcased by the blended polymer thin film based OPT as compared to its pristine polymer thin film based counterpart which had a µ of 0.001 cm2V-1s-1 and an Ion/Ioff of 9 × 103. Further, the blended polymer thin film based OPT demonstrated a high photosensitivity of 6.6 × 103 and a photoresponsivity of 0.13 A/W towards white light which were much superior than those of many of the previously reported polymer thin film based OPTs. The results hold crucial significance towards the development of cost effective blended polymer thin film based OPTs.

DOI： 10.1088/1742-6596/2070/1/012040

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85120428279&origin=inward

Implication of color of sensitizing dyes on transparency and efficiency of transparent dye-sensitized solar cells 査読有り 国際誌

Roy P., Vats A.K., Tang L., Pandey S.S.

Solar Energy   225   950 - 960   2021年09月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Dye-sensitized solar cells (DSSCs) are one of the potential candidates for the fabrication of colourful and see-through solar cells for energy harvesting esthetic windows. However, a trade-off between transparency and power conversion efficiency (PCE) has to be tackled amicably to realize the solar cells with good PCE and transparency. Judicious selection of dyes to bypass the light absorption in the high eye-sensitivity region (500–600 nm) is one of the plausible solutions. This was demonstrated utilizing yellow (D-131) and red (N-719) commercial dyes along with newly developed blue (SQ-138) and green coloured (SQ-140) dyes with intense and sharp light absorption mainly in the far-red to near-infrared (NIR) wavelength region. Transparent DSSCs fabricated using the most commonly used red-coloured dye N-719 although exhibited an increase in the PCE from 2.9% to 5.3% upon increasing the thickness of the transparent TiO2 layer from 4 μm to 10 μm but resulted in a serious loss in the average visible transparency (AVT) from 58.6% to 7.3% making the DSSC non-transparent. Contrary to this, under similar thickness variations, dyes D-131, SQ-138 and SQ-140 exhibiting very high AVT of >70% maintained the AVT > 40%, which is necessary for good visual perception.

DOI： 10.1016/j.solener.2021.08.014

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85112239425&origin=inward

Investigation of Orientation in the Thin Films of Conjugated Polymer and NIR Dye Blends Fabricated by Friction Transfer Method 査読有り

Yuki Kurokawa, Shuichi Nagamatsu, Shyam S Pandey

IEEE Explore ( IEEE )   2021年08月

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Conference: 28th International Workshop on Active Matrix, Flatpanel Displays and Devices (AM-FPD21)A   2021年06月29日  -  2021年07月02日

Improved film’s crystallinity and facile charge transport has been well demonstrated by orienting conjugated polymers using solution based thin film fabrication followed by thermal annealing, need for huge halogenated solvents and high temperature annealing are stumbling block for industrially viable large area thin film fabrication. Herein, we report the fabrication of oriented thin films regioregular P3HT by solvent-free friction transfer (FT) technique and enhancement its further enhancement by adding NIR sensitive squaraine dyes. Apart from assisting the molecular orientation of P3HT, it has been demonstrated that dye molecules are also get oriented and a synergistic match between the alkyl chains of the polymer and dye molecule leads to promotion for the extent of the molecular orientation in the dye molecules.

DOI： 10.23919/AM-FPD52126.2021.9499214

その他リンク： https://ieeexplore.ieee.org/document/9499214

Extreme Orientational Uniformity in Large-Area Floating Films of Semiconducting Polymers for Their Application in Flexible Electronics 査読有り

Manish Pandey, Heriyanto Syafutra, Nikita Kumari, Shyam S. Pandey, Ryo Abe, Hiroaki Benten, and Masakazu Nakamura

ACS Applied Materials & Interfaces ( American Chemical Society )   2021年08月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Layer-by-layer fabrication of uniformly oriented thin films over large areas by cost-effective solution-based approaches can open new horizons for the realization of high-performance organic circuits in various applications. In this work, fabrication of a large-area ≈40 cm2 film with uniform orientation is reported for poly(3,3‴-dialkylquaterthiophene) (PQT) using a unidirectional floating film transfer method (UFTM). Orientation characteristics and charge transport anisotropy were analyzed using polarized UV–vis spectral mapping and fabrication of bottom-gated organic field-effect transistors (OFETs) from different regions. Films were found to be highly oriented with an optical dichroic ratio of ca. 15. Orientation characteristics reveal that films were highly oriented along the width of the film, covering >70% of the area, and angle-dependent field-effect mobilities are in good agreement with the orientation of the polymer backbones. These highly oriented films resulted in charge transport anisotropy of 8.9. An array of bottom-gated OFETs fabricated along the length of single large-area (≈15 × 2.5 cm2) thin film demonstrated the average field-effect mobility of 0.0262 cm2/(V s) with a very narrow standard deviation of 12.6%. We also demonstrated that film thickness can be easily tuned from 5.6 to 45 nm by increasing the PQT concentration, and field-effect mobility is highly reproducible even when the film thickness is 10 nm. Microstructural characterization of the thus-prepared large-area thin films revealed the edge-on stacked polymer backbones and surface roughness of <1 nm as probed by grazing incidence X-ray diffraction and atomic force microscopy, respectively. Flexible OFETs with bottom-gate top-contact geometry were also fabricated, having average field-effect mobility of 0.0181 cm2/(V s). There was no considerable change in mobility after bending the flexible devices at different radii.

DOI： 10.1021/acsami.1c09671

その他リンク： https://pubs.acs.org/doi/abs/10.1021/acsami.1c09671

Assisted alignment of conjugated polymers in floating film transfer method using polymer blend 査読有り

Heriyanto Syafutra, Manish Pandey, Nikita Kumari, Shyam S Pandey, Hiroaki Benten, Masakazu Nakamura

Thin Solid Films ( Elsevier )   734   138814(1) - 138814(8   2021年07月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Orientating conjugated polymers (CPs) in thin films is an attractive technique for obtaining anisotropic properties, resulting in improved device performances. Template-assisted alignment using pre-patterned substrates has been widely used to orient various polymers irrespective of their orientation capability. In this work, we report that using the floating film transfer method, the orientation of guest polymers can be in-situ assisted via blending with a host polymer during film fabrication. Dichroic Ratio (DR) of two guest CPs such as poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno[3,2-b]thiophene)] and poly(9,9-di-n-octylfluorenyl-2,7-diyl) were found to be enhanced when blended with host polymer poly(3,3‴-didodecyl-quaterthiophene) (PQT). DR of the host PQT decreases monotonically with an increase in the guest polymer proportion, suggesting that guest polymers are well mixed in the host matrix. The electronic absorption spectra and atomic force microscopy results revealed that blended polymers were well mixed without any phase separation. DR of the guest polymers in the blend was the same even when the overall blend concentration was increased twice to increase the overall film thickness.

DOI： 10.1016/j.tsf.2021.138814

その他リンク： https://www.sciencedirect.com/science/article/pii/S0040609021002972

Development of High-Sensitivity Poly (2, 7-(9, 9-dioctylfluorene)-alt-5, 5-(4', 7'-di-2-thienylbenzo [c][1, 2, 5] thiadiazole)) Thin-Film-Based Phototransistors by the Ribbon-Floating Film Transfer Method 査読有り 国際誌

Nidhi Yadav, Nikita Kumari, Yoshito Ando, Shyam S. Pandey, and Vipul Singh

Physica Status Solidi (RRL) - Rapid Research Letters ( WILEY-V CH VERLAG GMBH )   2021年06月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Alignment of polymer chains hold key to development of highly functional polymer based field effect transistors. Our recently developed ribbon-floating film transfer method (ribbon-FTM) has the potential for development of polymer thin films with highly aligned chains which are desirable for fabrication of efficient planar devices. These thin films consisting of well aligned polymer chains exhibit high degree of optical and electronic anisotropies. In this work we report ribbon-FTM processed thin film based organic photosensitive transistors of PFO-DBT. Under optimized fabrication conditions polymer FETs based on PFO-DBT demonstrated a charge carrier mobility of 0.002 cm²/Vs and an on-off ratio of 5 × 10⁴ under dark conditions. The devices have further demonstrated a Photosensitivity of ∽10⁴ and 10³ and a high Responsivity of 8.37 A/W and 4.6 A/W against green and red light illuminations, respectively. The results hold promise for development of conducting polymer based high performance photosensitive OFETs. This article is protected by copyright. All rights reserved.

DOI： 10.1002/pssr.202100185

その他リンク： https://onlinelibrary.wiley.com/doi/epdf/10.1002/pssr.202100185

Probing the metal/conducting polymer interface and implications of the metal diffusion in two-terminal sandwich devices 査読有り 国際誌

Nidhi Yadav, Nikita Kumari, Yoshito Ando, Shyam S Pandey, Vipul Singh

Synthetic Metals ( Elsevier )   278   116797(1) - 116797(11)   2021年05月

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記述言語：英語   掲載種別：研究論文（学術雑誌）

In this article, we have investigated the role of polymer regio-regularity and film fabrication technique in reducing metal diffusion from top electrodes in sandwich type devices. Poly(3-hexyl thiophene)(P3HT) polymer of varying regio-regularity was chosen for investigation and its corresponding thin films were fabricated by spin-coating(SC) and floating film transfer method(FTM). Sandwich devices with a top interface between gold and i) FTM coated regio-regular (rr) P3HT, ii) FTM coated non-regiocontrolled (nr) P3HT, iii) SC nr-P3HT and iv) SC rr-P3HT were fabricated. The current density vs voltage (J-V) characteristics of the devices revealed non-ohmic characteristics. Estimation of interfacial hole barrier heights using Fowler Nordheim tunneling model revealed a small barrier of 1.12 eV for the isotropic spin-coated nr-P3HT film which increased to 1.37 eV with an increase in film anisotropy for the FTM nr-P3HT film. The barrier height also gradually declined from 1.37 eV to 1.05 eV with increase in regioregularity from FTM nr-P3HT to FTM rr-P3HT. These observations were confirmed through optical and structural characterizations along with depth profiling of metal diffusion using XPS. Pronounced Au diffusion to a higher depth was observed in the XPS results for the highly anisotropic FTM film that decreased subsequently with decrease in anisotropy from FTM to spin-coated film. It was thus deduced that a judicious selection of fabrication technique and polymer aids in reducing metal diffusion leading to improved device performance. The results hold crucial significance towards the fabrication of efficient organic photodetectors that have a sandwich type device architecture.

DOI： 10.1016/j.synthmet.2021.116797

その他リンク： https://www.sciencedirect.com/science/article/pii/S0379677921001028

Development of PCPDTBT thin film based highly sensitive organic phototransistors 査読有り 国際誌

Nidhi Yadav, Nikita Kumari, Shyam S Pandey, Vipul Singh

Materials Today' Proceeding ( Elsevier )   2021年04月

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this report, we have proposed a novel ribbon-FTM method to develop highly oriented polymer thin films. A donor–acceptor (D-A) type copolymer, PCPDTBT has been selected as the target material for investigation. The maximally oriented film showcased a DR of 4.1. Highly aligned polymer film was used as the active layer for the development of bottom gate bottom contact (BGBC) type OFETs. An average mobility and an Ion/Ioff of 0.002 cm2/Vs and 5 × 103 were obtained under dark conditions, respectively. Upon illumination with monochromatic green light (λ = 522 nm, Pin = 0.5 mW/cm2), the OPTs showcased a high photosensitivity and responsivity of 103 and 17 A/W, respectively. The obtained values were found to be superior over many of the previously reported similar OPTs which employed other organic polymers. The results thus are of crucial significance with respect to the development of facile, cost effective and highly sensitive single polymer thin film based OPTs.

DOI： 10.1016/j.matpr.2021.03.468

その他リンク： https://www.sciencedirect.com/science/article/pii/S2214785321025232?via%3Dihub

Fatigue life prediction of electroactive polymer strain sensor 査読有り

Nitin Kumar Singh, Kazuto Takashima, Shyam Sudhir Pandey

Electroactive Polymer Actuators and Devices (EAPAD) XXIII ( International Society for Optics and Photonics )   11587   115871Z(1) - 115871Z(7)   2021年03月

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

USA   Sandiego, California   2021年03月22日  -  2021年03月27日

Electroactive polymers strain sensors bear a great potentiality in the area of soft robotics, wearable devices, and fitness industries. A small initial defect present in such sensor may grow to a critical size during contraction and relaxation cycles leading to mechanical failure, therefore, prediction of fatigue life is inevitable. The crack growth approach is one of the amicable ways to estimate the fatigue life considering parameters like tear energy, crack geometry, and power law. In this work, crack growth approach based on power law is being proposed to predict fatigue life utilizing conducting and stretchable freestanding films consisted of SEBS rubber and dodecyl benzenesulfonic acid (DBSA) doped polyaniline composite. Utilizing this crack growth model for the prediction of fatigue life exhibited that such films can sustain more than a million cycles even at a large value of deformation.

DOI： 10.1117/12.2584521

その他リンク： https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11587/115871Z/Fatigue-life-prediction-of-electroactive-polymer-strain-sensor/10.1117/12.2584521.short