Faculty Profiles - PANDEY Shyam sudhir

Papers - PANDEY Shyam sudhir

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Role of device architecture and AlOX interlayer in organic Schottky diodes and their interpretation by analytical modeling Reviewed

Nikita Kumari, Manish Pandey, Kengo Hamada, Daisuke Hirotani, Shuichi Nagamatsu, Shuzi Hayase, Shyam S Pandey

Journal of Applied Physics ( American Institute of Physics ) 126 125501-1 - 125501-12 2019.09

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Considering the pivotal role of interfaces in controlling the performance of organic electronic devices, implications of metal/organic interfacial quality in a Schottky barrier diode (SBD) are investigated. The nature of metal/organic interfaces and the thin film quality of regioregular poly (3-hexylthiophene) based SBDs fabricated in different device architectures are investigated using experimental and theoretical modeling. The importance of oxidized aluminum nanostructures as an interlayer at the Schottky interface for the dramatic enhancement of the rectification ratio (>106 at ±5 V) has been demonstrated, which is attributed to suppressed leakage current due to the oxide layer and the formation of a charge double layer. Furthermore, electrical performances of all the SBDs were modeled in terms of an underlying particular phenomenon solely or with the combination of multiple physical phenomena. The combined modeling equation used in this work fits well for the different device architectures, which validates its generality in order to extract the device parameters

DOI： 10.1063/1.5109083

Other Link： https://aip.scitation.org/doi/full/10.1063/1.5109083

Recent advances in the orientation of conjugated polymers for organic field-effect transistors Reviewed

Manish Pandey, Nikita Kumari, Shuichi Nagamatsu, Shyam S Pandey

Journal of Materials Chemistry ( Royal Society of Chemistry ) 7 13323 - 13351 2019.09

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Solution processable conjugated polymers (CPs) possess unique molecular structures in terms of extended π-conjugation in combination with quasi 1-dimensionality, imparting them with an inherent tendency for molecular self-assembly and ultimately determining their optoelectronic properties. Short-range molecular ordering and long-range macroscopic orientation are two different but interdependent phenomena, which should be optimized depending on the nature of electronic devices (planar versus vertical). Judicious control of the macromolecular orientations and conformation-assisted morphologies of CPs are key for determining and controlling the anisotropic charge transport in organic field effect transistors (OFETs). The present review focuses on different solution-based approaches for thin film fabrication developed in the last two decades aimed towards controlling the film morphologies and macroscopic

DOI： 10.1039/C9TC04397G

Kyutacar

Other Link： https://pubs.rsc.org/no/content/articlelanding/2019/tc/c9tc04397g/unauth#!divAbstract

Implication of Molecular Weight on Optical and Charge Transport Anisotropy in PQT-C12 Films Fabricated by Dynamic FTM Reviewed

Atul SM Tripathi, Shifumi Sadakata, Rakesh Kumar Gupta, Shuichi Nagamatsu, Yoshito Ando, Shyam S Pandey

ACS Applied Materials and Interfaces ( The American Chemical Society ) 11 ( 31 ) 28088 - 28095 2019.07

Language：English Publishing type：Research paper (scientific journal)

Large area (>20 cm × 2 cm)-oriented thin films of PQT-C12 with varying molecular weight and polydispersity index (PDI) were fabricated by the ribbon-shaped floating film transfer method aiming toward their application as an active semiconductor element of organic field effect transistors (OFETs). Investigation on the influence of the molecular weight and PDI upon the extent of molecular alignment and anisotropic charge transport was systematically carried out. It has been demonstrated that high molecular weight in combination with low PDI not only leads to a very high optical anisotropy >10 but also high charge carrier anisotropy with a hole mobility of about 0.07 cm2/V·s for OFETs using parallel-oriented PQT-C12 thin films. Such a structure–property correlation is highly beneficial for the development of high performance organic electronic devices by synergistic and amicable tuning of the optoelectronic anisotropies and polymer synthetic variables.

Kyutacar

Other Link： https://doi.org/10.1021/acsami.9b06568

Wide wavelength photon harvesting in dye-sensitized solar cells utilizing cobalt complex redox electrolyte: Implication of surface passivation Reviewed

Anusha Pradhan, Maryala Saikiran, Gaurav Kapil ,Shuzi Hayase, Shyam S. Pandey

Solar Energy Materials and Solar Cells ( Elsevier ) 195 122 - 133 2019.03

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

A combination of near infra-red (NIR) photon harvesting and cobalt electrolytes having deeper redox energy level are needed for the fabrication of high efficiency dye-sensitized solar cells (DSSCs). A logical molecular design of unsymmetrical squaraine dye (SQ-110) as a representative of NIR dyes has been demonstrated to function well in DSSC using cobalt complex redox electrolyte. Problem of mass transport limitations due to the bulky cobalt complex ions leading to relatively enhanced charge recombination was amicably solved by single as well as multiple compact metal oxide surface passivation on both of the transparent conducting oxide substrate as well as mesoporous TiO2. Complete absence of light absorption beyond 550 nm wavelength region by D-35 and utilization of a complementary light harvesting dye SQ-110 led to efficient wide wavelength photon harvesting. DSSC fabricated using a dye cocktail of D-35 and SQ-110 in 4:1 ratio resulted in to photoconversion efficiency (PCE) of 7.2%, which is much higher as compared to the constituent individual sensitizers D-35 (3.6%) and SQ-110 (1.9%). This synergistic enhancement in PCE by dye cocktail was associated with the mutual co-operation of respective dyes in terms controlling the dye aggregation and complementary photon harvesting. In this dye cocktail system, D-35 is involved in the prevention of dye aggregation, lower wavelength photon harvesting and energy transfer induced photocurrent enhancement.

DOI： 10.1016/j.solmat.2019.03.013

Kyutacar

Optoelectrical anisotropy in graphene oxide supported polythiophene thin films fabricated by floating film transfer Reviewed

Rajiv K Pandey, Atul SM Tripathi, Shyam S Pandey, Rajiv Prakash

Carbon ( Elsevier ) 147 252 - 261 2019.03

Language：English Publishing type：Research paper (scientific journal)

A facile method for the fabrication of highly oriented hybrid thin films of conjugated polymer (CP) with graphene oxide (GO) as 2D nano-filler over the high surface tension liquid substrate by floating film transfer is being reported. Formation of the self-assembled oriented hybrid thin film has been validated using multiple characterization techniques. Hybrid thin films thus prepared have been used for the fabrication of organic field effect transistors (OFETs) followed by investigation of anisotropic charge carrier transport. OFETs made with hybrid films oriented in channel direction exhibited the superior device performance with >6 fold augmentation in field effect mobility (μ) and one order improvement in on/off ratio as compared to that of devices based on pristine CP. However, pristine polymer shows 2.2 fold enhancement in mobility and one order augmentation in on/off ratio in parallel orientation as compared to the corresponding perpendicularly oriented films. Thus, our study has elucidated a path to obtain oriented, aligned, and self - assembled hybrid films for further improvement in the device performance aiming towards the applications in organic electronics.

DOI： 10.1016/j.carbon.2019.02.086

Kyutacar

Other Link： https://www.sciencedirect.com/science/article/pii/S0008622319302179

Passivation of Grain Boundary by Squaraine Zwitterions for Defect Passivation and Efficient Perovskite Solar Cells Reviewed

Zhen Wang, Anusha Pradhan, Muhammad Akmal kamarudin, Manish Pandey, Shyam S Pandey, Putao Zhang, Chi huey Ng, Atul SM Tripathi, Tingli Ma, Shuzi Hayase

ACS Applied Materials and Interfaces ( The American Chemical Society ) 11 ( 10 ) 10012 - 10020 2019.02

Language：English Publishing type：Research paper (scientific journal)

Unavoidable defects in grain boundaries (GBs) are detrimental and critically influence the organometal halide perovskite performance and stability. To address this issue, semiconducting molecules have been employed to passivate traps along perovskite GBs. Here, we designed and synthesized three squaraine molecules (SQ) with zwitterionic structure to interact with under-coordinated Pb2+ and passivate Pb–I antisite defects. Density functional theory calculation shows symmetric O atoms could coordinate with perovskite grains simultaneously, resulting in continuous charge distribution at the SQ–perovskite interface. The energetic traps distribution in CH3NH3PbI3 perovskite is influenced significantly by the interaction between SQ and perovskite as analyzed by thermally stimulated current, in which the deep-level defects are considerably reduced due to efficient SQ passivation. In addition, we explore how SQ …

DOI： 10.1021/acsami.8b22044

Other Link： https://pubs.acs.org/doi/abs/10.1021/acsami.8b22044

2D positional profiling of orientation and thickness uniformity in the semiconducting polymers thin films Reviewed

Nikita Kumari, Atul SM Tripathi, Shifumi Sadakata, Manish Pandey, Shuichi Nagamatsu, Shuzi Hayase, Shyam S Pandey

Organic Electronics ( Elsevier ) 68 221 - 229 2019.02

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Harnessing the full potential of solution processable conjugated polymers (CPs) as active semiconductor elements lies in the facile thin film fabrication along with amicable control of molecular self-assembly and orientation. Probing the nature and uniformity of thin films are inevitable for fabrication of devices with high reproducibility. Herein, a new method for the fast and facile profiling of thickness and molecular orientation of large area thin films is being reported. Thin films of PBTTT-C14 fabricated by three different methods like floating film transfer method (FTM), friction transfer and spin coating were subjected to profiling of thickness and molecular orientation using 2D positional mapping system followed by fabrication of organic thin film transistors. In order to prove applicability of the mapping system on other CPs, oriented films of PQT-C12 were also prepared by FTM and optical anisotropy estimated by the mapping system (23.0) and conventional spectrophotometer (22.4) validates the performance of our positional mapping system. Spin-coated thin films of PBTTT-C14 subjected to positional profiling of the film uniformity revealed that films are non-uniform and there was a gradual increase in the thickness from center to the periphery.

DOI： 10.1016/j.orgel.2019.02.011

Kyutacar

Other Link： https://www.sciencedirect.com/science/article/pii/S1566119919300746

Back-illuminated dye-sensitized solar cell flexible photoanode on titanium foil Reviewed

Shaban S., Shafie S., Pandey S.S., Lokman M.Q., Ahmad F., Hamidon M.N., Sharif N.F.M.

ASM Science Journal 12 ( SpecialIssue4 ) 29 - 35 2019.01

Language：English Publishing type：Research paper (scientific journal)

© 2019, Akademi Sains Malaysia. This paper reports the preparation and performance analysis on dye-sensitized solar cells (DSSC) using titanium (Ti) foil as flexible photoanode for back-illuminated measurement. Performance differences were also carried with the fluorine-doped tin oxide (FTO) glass photoanode using the back and front-illuminated technique. The hydrogen peroxide (H2O2) treated Ti foil surface was applied and the doctor blade method was used for deposition on photoanode during the process of fabrication. Surface morphology of the treated Ti Foil with H2O2 shows the formation of TiO2 nanostructure which results in significant attachment of TiO2 layer on Ti Foil. The results on measurement show that the fabricated flexible photoanode DSSC has an efficiency of power conversion at 1.00% under 1.5 A. M solar radiation by using back-illuminated while DSSC with solid-state glass photoanode has an efficiency power conversion at 0.53% (back-illuminated) and 2.22% (front-illuminated). However, the flexible photoanode DSSC has better power conversion efficiency than the solid-state glass photoanode DSSC under the condition of back-illumination. It is lower in result comparatively with front illumination DSSC due to the coated of platinum at the counter electrode that reflects light partially, while electrolyte iodine absorbs some photons and effects on DSSC performance.

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85084484893&origin=inward

Synthesis, characterizations and photo-physical properties of novel lanthanum (III) complexes Reviewed

Iffat Ameen, Abhishek Kumar Tripathi, Afshan Siddiqui, Gaurav Kapil, Shyam S Pandey, Umesh Nath Tripathi

Journal of Taibah University for Science 12 ( 6 ) 796 - 808 2018.11

Facile fabrication of large area oriented conjugated polymer films by ribbon-shaped FTM and its implication on anisotropic charge transport Reviewed

Atul S.M.Tripathi, Nikita Kumari, Shuichi Nagamatsu, Shuzi Hayase, Shyam S.Pandey

Organic Electronics ( Elsevier ) 65 1 - 7 2018.10

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Facile fabrication of large area [20 cm (L) × 2 cm (W)] uniform and oriented thin films of a variety of conjugated polymers (CPs) with minimal material wastage has been successfully demonstrated using our newly developed ribbon-shaped floating film transfer method (FTM). Under identical film fabrication conditions of FTM like hydrophilic liquid substrate consisted of ethylene glycol and glycerol (3:1), the temperature of 60 °C and polymer concentration 1% (w/w) in chloroform, order of molecular orientation was found to be PQT-C12 > F8T2 > NR-P3HT > PBTTT-C14 > PTB7. Depending on the nature of polymeric backbone, CPs exhibited different optical anisotropies in their oriented thin films, which was explained in terms of nature and rigidity of polymeric chains in the light of persistent length. Organic field effect transistors fabricated using these CPs exhibited clear p-type behaviour and anisotropic charge transport. Amongst various CPs used, PQT-C12 not only exhibited the highest optical anisotropy (DR = 5.1) but also highest anisotropic charge transport (μ||/μ⊥ = 7.1). Ribbon-shaped thin films of PQT-C12 prepared by slider based FTM exhibited best device performance with charge carrier mobility of 5.0 × 10−2 cm2/V and ON/OFF ratio of 106, when films were oriented parallel to the channel direction. Interestingly, a mobility of parallel oriented thin films prepared by FTM was about two orders of magnitude higher compared to the OFETs fabricated using conventional spin coating (6.7× 10−4 cm2/V).

DOI： 10.1016/j.orgel.2018.10.043

Kyutacar

Other Link： https://www.sciencedirect.com/science/article/pii/S1566119918305585

Synthesis and Optoelectrical Characterization of Novel Squaraine Dyes Derived from Benzothiophene and Benzofuran Reviewed

G. Hanumantha Rao, Manish Pandey, Kamatham Narayanaswamy, Ravulakollu Srinivasa Rao, Shyam S. Pandey, Shuzi Hayase, and Surya Prakash Singh

ACS Omega 3 ( 10 ) 13919 - 13927 2018.10

Enhancement of charge transport in quantum dots solar cells by N-butylamine-assisted sulfur-crosslinking of PbS quantum dots Reviewed

Zhen Wang, Zhaosheng Hu, Muhammad Akmal Kamarudin, Gaurav Kapil, Atul Tripathi, Qing Shen, Kenji Yoshino, Takashi Minemoto, Sham S. Pandey, Shuzi Hayase

Solar Energy 174 399 - 408 2018.09

Synthesis and Photophysical Characterization of Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells utilizing Cobalt Electrolytes Reviewed

Anusha Pradhan, Maryala Saikiran, Gaurav Kapil, Shuzi Hayase, and Shyam Sudhir Pandey

ACS Applied Energy Materials 1 ( 9 ) 4545 - 4553 2018.08

A review of transparent solar photovoltaic technologies Reviewed

Alaa AF Husain, Wan Zuha W Hasan, Suhaidi Shafie, Mohd N Hamidon, Shyam Sudhir Pandey

Renewable and Sustainable Energy Reviews 94 779 - 791 2018.07

Study Pertaining to Observe the Effect of PbI2 Passivation on Carbon Electrode for Perovskite Solar Cells by Quartz Crystal Microbalance System Reviewed

Putao Zhang, Gaurav Kapil, Kengo Hamada, Shyam Sudhir Pandey, Tingli Ma, Shuzi Hayase

ACS Sustainable Chemistry & Engineering 6 ( 8 ) 10221 - 10228 2018.06

Anisotropic charge transport in highly oriented films of semiconducting polymer prepared by ribbon-shaped floating film Reviewed

Atul SM Tripathi, Manish Pandey, Shifumi Sadakata, Shuichi Nagamatsu, Wataru Takashima, Shuzi Hayase, Shyam S Pandey

112 ( 12 ) 123301-1 - 123301-5 2018.03

Implications of doping and depletion on the switching characteristics in polymer-based organic field-effect transistors Reviewed

Shashi Tiwari, Manish Pandey, Wataru Takashima, Shuichi Nagamatsu, SK Balasubramanian, Shuzi Hayase, Shyam S Pandey, Rajiv Prakash

Organic Electronics 56 152 - 158 2018.02

Rapid Formation and Macroscopic Self-Assembly of Liquid-Crystalline, High-Mobility, Semiconducting Thienothiophene Reviewed

Manish Pandey, Ashwathanarayana Gowda, Shuichi Nagamatsu, Sandeep Kumar, Wataru Takashima, Shuzi Hayase, Shyam S. Pandey

Advanced Materials Interfaces 5 ( 6 ) 1700875(1) - 1700875(11) 2018.01

Casting Control of Floating-films into Ribbon-shape Structure by modified Dynamic FTM Reviewed

Tripathi, M Pandey, S Nagamatsu, SS Pandey, S Hayase, W Takashima

Journal of Physics: Conference Series 924 ( 1 ) 012014(1) - 012014(6) 2017.11

Photophysical Characterization and BSA Interaction of Direct Ring Carboxy Functionalized Symmetrical squaraine Dyes Reviewed

Maryala Saikiran, Shyam S Pandey, Shuzi Hayase, Tamaki Kato

Journal of Physics: Conference Series 924 ( 1 ) 012006(1) - 012006(10) 2017.11

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Papers - PANDEY Shyam sudhir