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Solution-processed 2-dimensional hole-doped ionic graphene compounds

F.Y. Kam 1, R.Q. Png 2, M.C.Y. Ang 1, P. Kumar 2, K Rubi 2, R. Mahendiran 2, O. Solomeshch 3, N. Tessler 3, G.K. Lim 2,4, L.L. Chua 1, P.K.H. Ho 2. Materials Horizons 3 (2017) 456 Abstract

1Department of Chemistry, NUS, 2Department of Physics, NUS, 3Department of Electrical Engineering, Technion, 4DSO National Laboratories, Singapore

Interface Doping for Ohmic Organic Semiconductor Contacts Using Self-Aligned Polyelectrolyte Counterion Monolayer

W.L. Seah 1, C.G.Y. Tang 1, R.Q. Png 1, V. Keerthi 2, C. Zhao 1, H. Guo 2, J.G. Yang 1, M. Zhou 3, P.K.H. Ho 1, L.L. Chua 1,2. Adv. Funct. Mater. 27 (2017) Online Early View Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS, 3BASF South East Asia Pte Ltd

Doped polymer semiconductors with ultrahigh and ultralow work functions for ohmic contacts

C.G.Y. Tang 1,2, M.C.Y. Ang 2,3, K.K. Choo 3, V. Keerthi 3, J.K. Tan 1,2, M.N. Syafiqah 3, T. Kugler 4, J.H. Burroughes 4, R.Q. Png 1,2, L.L. Chua 1,2,3, P.K.H. Ho 1,2. Nature 539 (2016) 536 Abstract

1Department of Physics, NUS, 2Solar Energy Research Institute of Singapore, NUS, 3Department of Chemistry, NUS, 4Cambridge Display Technology Ltd

Madelung and Hubbard interactions in polaron band model of doped organic semiconductors

R.Q. Png 1,2, M.C.Y. Ang 2,3, M.H. Teo 1, K.K. Choo 3, C.G.Y. Tang 1,2, D. Belaineh 1, L.L. Chua 1,2,3, P.K.H. Ho 1,2. Nature Communications 7 (2016) 11948 Abstract

1Department of Physics, NUS, 2Solar Energy Research Institute of Singapore, NUS, 3Department of Chemistry, NUS

Characterization of ohmic contacts in polymer organic field-effect transistors

J.G. Yang 1,3, W.L. Seah 1, H. Guo 2, J.K. Tan 1, M. Zhou 5, R. Matsubara 4, M. Nakamura 4, R.Q. Png 1, P.K.H. Ho 1, L.L. Chua 1,2. Org. Electron. 37 (2016) 491 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS, 3NUS Graduate School, NUS, 4Graduate School of Materials Science, NAIST, 5BASF South East Asia Pte Ltd

Perfluorinated ionomer-modified hole-injection layers: Ultrahigh-workfunction but nonohmic contacts

D. Belaineh 1, J.K. Tan 1, R.Q. Png 1, P.F. Dee 1, Y.M. Lee 1, B.N.N. Thi 1, N.S. Ridzuan 1, P.K.H. Ho 1. Adv. Funct. Mater. 25 (2015) 5504 Abstract

1Department of Physics, NUS

Influence of Interfacial Area on Exciton Separation and Polaron Recombination in Nanostructured Bilayer All-Polymer Solar Cell

T.Pfadler 2, M.Coric 2, C.M. Palumbiny 3, A.C. Jakowetz 2, K-P. Strunk 2, J.A. Dorman 2, P. Ehrenreich 2, C. Wang 3, A. Hexemer 3, R.Q. Png 1, P.K.H Ho 1, P. Müller-Buschbaum 4, J. Weickert 2, L. Schmidt-Mende 2. ACS Nano. 8 (2014) 12397 Abstract

1Department of Physics, NUS, 2Department of Physics, UKON, 3Lehrstuhl für Funktionelle Materialien, Physik Department E13, TUM, 4 Experimental Systems Advanced Light Source, Lawrence Berkeley National Lab

A High-performance p-doped conducting polymer blend based on sulfonated polyalkoxythiophene and poly(4-hydroxystyrene)

D. Belaineh 1, R.Q. Png 1, C.L. McGuiness 2, M. Mathai 2, V. Seshadri 2, P.K.H. Ho 1.Chem. Mater. 26 (2014) 4724 Abstract

1Department of Physics, NUS, 2Solvay OLED, Plextronics

A transition solvent strategy to print polymer:fullerene films using halogen-free solvents for solar cell applications

G.H. Lim1,3, J.M. Zhuo1,2, L.Y. Wong1, S.J. Chua3, L.L. Chua1,2, P.K.H. Ho 1,4. Org. Electron. 15 (2014) 449 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS, 3Department of Electrical and Computer Engineering, NUS, 4Solar Energy Research Institute of Singapore, NUS

Evalution of built-in potential and loss mechanisms at contacts in organic solar cells: device model parameterisation, validation, and prediction

B. Liu 1, R.Q. Png 1,2, J.K. Tan 1,2, P.K.H. Ho 1,2. Adv. Energy. Mater. 4 (2014) 1200972 Abstract

1Department of Physics, NUS, 2Solar Energy Research Institute of Singapore, NUS

Efficient surfactant-free and chemical reductant-free solvothermal deoxidation of solution-processable sub-stoichiometric graphene oxide

Z.L. Chen1, F.Y. Kam2, V. Keerthi2, J. Song2, C. Hu2, L.Y. Wong1, G.K. Lim1,3, L.L. Chua1,2. J. Mater. Chem. C 1 (2013) 7246 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS, 3DSO National Laboratories, Singapore

Suppressing recombination in polymer photovoltaic devices via energy-level cascades

Z.K. Tan1, K. Johnson1, Y. Vaynzof1, A.A. Bakulin2, L.L. Chua3, P.K.H. Ho4, R.H. Friend1 Adv. Mater. 25 (2013) 4131 Abstract

1Cavendish Laboratory, University of Cambridge, 2FOM institute AMOLF, The Netherlands, 3Department of Chemistry, NUS, 4Department of Physics, NUS

Influence of graphite source on chemical oxidative reactivity

Z.L. Chen2, F.Y. Kam1, R.G.S. Goh2, J. Song1, G.K. Lim2,3, L.L. Chua1,2 Chemistry of Materials 25 (2013) 2944 Abstract

1Department of Chemistry, NUS, 2Department of Physics, NUS, 3DSO National Laboratories, Singapore

A general method for transferring graphene onto soft surfaces

J. Song1, F.Y. Kam1, R.Q. Png2, W.L. Seah2, J.M. Zhuo2, G.K. Lim 2,3, P.K.H. Ho2, L.L. Chua1,2 Nature Nanotechnology 8 (2013) 356 Abstract

1Department of Chemistry, NUS, 2Department of Physics, NUS, 3DSO National Laboratories, Singapore

Donor-acceptor interface modification by zwitterionic conjugated polyelectrolytes in polymer photovoltaics

A. Kumar1, G. Pace1, A.A. Bakulin1, J.F. Fang2, P.K.H. Ho3, W.T.S. Huck 2, R.H. Friend1, N.C. Greenham1 Energy & Environmental Science 6 (2013) 1589 Abstract

1Cavendish Laboratory, University of Cambridge, 2Melville Laboratory for Polymer Synthesis, University of Cambridge, 3Department of Physics, NUS

Jettable fluid space and jetting characteristics of a microprint head

L.Y. Wong1, G.H. Lim1,2, T. Ye1, F.B.S. Silva1, J.M. Zhuo1, R.Q. Png1, S.J. Chua2, P.K.H. Ho1 Journal of Fluid Mechanics 713 (2012) 109 Abstract

1Department of Physics, NUS, 2Department of Electrical and Computer Engineering, NUS

High internal quantum efficiency in fullerene solar cells based on crosslinked polymer donor networks

B. Liu1, R.Q. Png1, L.H. Zhao2, L.L. Chua1,2, R.H. Friend1,3, P.K.H. Ho1,4 Nature Communications 3 (2012) 1321 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS, 3Cavendish Laboratory, University of Cambridge, 4Solar Energy Research Institute of Singapore, NUS

Furan substituted diketopyrrolopyrrole and thienylenevinylene based low band gap copolymer for high mobility organic thin film transistors

P. Sonar1, J.M. Zhuo2, L.H. Zhao3, K.M. Lim2, J.H. Chen4, A.J. Rondinone4, S.P. Singh1,5, L.L. Chua2,3, P.K.H. Ho2, A. Dodabalapur1,6 Journal of Materials Chemistry 22 (2012) 17284 Abstract

1Institute of Materials Research and Engineering (IMRE), A*STAR, 2Department of Physics, NUS, 3Department of Chemistry, NUS, 4Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 5School of Natural Sciences, Shiv Nadar University, 6Microelectronics Research Centre, The University of Texas at Austin

Polarization effects on energy-level alignment at the interfaces of polymer organic semiconductor films

L.H. Zhao1,2, R.Q. Png1, C.C.H. Chiam1, H. Guo1, J.M. Zhuo1, L.L. Chua1,2, A.T.S. Wee1, P.K.H. Ho1 Applied Physics Letters 101 (2012) 053304 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS

Effective work functions for the evaporated metal/organic semiconductor contacts from in-situ diode flatband potential measurements

M. Zhou1, R.Q. Png1, S.H. Khong2, S. Sivaramakrishnan1, L.H. Zhao3, L.L. Chua1,2,3, R.H. Friend1,2, P.K.H. Ho1 Applied Physics Letters 101 (2012) 013501 Abstract

1Department of Physics, NUS, 2Cavendish Laboratory, University of Cambridge, 3Department of Chemistry, NUS

Role of borderline solvents to induce pronounced extended-chain lamellar order in π-stackable polymers

L.H. Zhao1, R.Q. Png1, J.M. Zhuo2, L.Y. Wong1, J.C. Tang2, Y.S. Su1, L.L. Chua1,2 Macromolecules 44 (2011) 9692 Abstract

1Department of Physics, NUS, 2Department of Chemistry, NUS

Giant broadband nonlinear optical absorption response in dispersed graphene single sheets

G.K. Lim1,2, Z.L. Chen2, J. Clark4, R.G.S. Goh3, W.H. Ng1, H.W. Tan1, R.H. Friend2,4, P.H.K. Ho2, L.L. Chua2,3,4 Nature Photonics 5 (2011) 554 Abstract

1DSO National Laboratories, Singapore and 2Department of Physics, NUS, 3Department of Chemistry, NUS, 4Cavendish Laboratory, University of Cambridge

Surface-directed spinodal decomposition in poly[3-hexylthiophene] and C61-Butyric acid methyl ester blends

Y. Vaynzof1, D. Kabra1, L.H. Zhao2, L.L. Chua2, U. Steiner1, R.H. Friend1,2ACS Nano 5 (2011) 329 Abstract

1Cavendish Laboratory, University of Cambridge and 2Department of Physics, NUS

Improved electron injection in poly(9,9'-dioctylfluorene)- co-benzothiodiazole via cesium carbonate by means of coannealing

Y. Vaynzof1, D. Kabra1,L.L. Chua2, R.H. Friend1,2Applied Physics Letters 98 (2011) 113306 Abstract

1Cavendish Laboratory, University of Cambridge and 2Department of Physics, NUS

The dependence of device dark current on the active-layer morphology of solution-processed organic photodetectors

P. E. Keivanidis1,2, P.K.H. Ho3, R. H. Friend2,3, N. C. Greenham2 Advanced Functional Materials 20 (2010) 3895 Abstract

1Departments of Physics, Imperial College, 2Cavendish Laboratory, University of Cambridge and 3Department of Physics, NUS

Determination of the interface δ-hole density in a blue-emitting organic semiconductor diode by electromodulated absorption spectroscopy

M. Zhou1, R.Q. Png1, S. Sivaramakrishnan1, P.J. Chia1, C.K. Yong1, L.L. Chua1,2, P. K. H. Ho1 Applied Physics Letters 97 (2010)113505 Abstract

1Departments of Physics, and 2Chemistry, NUS.

Printable metal nanoparticle inks

B. T. Anto1, L.Y. Wong1, R.Q. Png1, S. Sivaramakrishnan1, L.L. Chua1,2, P. K. H. Ho1 Handbook of Nanophysics, Functional Nanomaterials. Chapter 2. ISBN: 978-1-4200-7552-6 Summary of book

1Departments of Physics, and 2Chemistry, NUS.

Interplay of processing, morphological order, and charge-carrier mobility in polythiophene thin films deposited by different methods: comparison of spin-Cast, drop-Cast, and inkjet-printed films

L.Y. Wong1,R.Q. Png1, F.B. Shanjeera Silva1, L.L. Chua1,2, D. V. Maheswar Repaka1, S. Chen1,3, X. Y. Gao1,3, L. Ke4, S. J. Chua4, A.T.S. Wee1,3, P. K. H. Ho1 Langmuir 26 (2010) 15494 Abstract

1Departments of Physics, and 2Chemistry, 3Singapore Synchrotron Light Source, NUS 4 Institute of Materials Research & Engineering, A*STAR.

Hydrophilic sparse ionic monolayer-protected metal nanoparticles: highly concentrated nano-Au and nano-Ag ‘‘inks’’ that can be sintered to near-bulk conductivity at 150°C

B.T. Anto1, S. Sivaramakrishnan1, L.L. Chua1,2, P.K.H. Ho2 Advanced Functional Materials 20 (2010) 296 Abstract

1Departments of Physics, and 2Chemistry, NUS.

Improved photoinduced charge carriers separation in organic-inorganic hybrid photovoltaic devices

Y. Vaynzof1, D. Kabra1, L.H. Zhao2, P.K.H. Ho2, A.T.S. Wee2, R.H. Friend1,2 Applied Physics Letters 97 (2010) 033309 Abstract

1Cavendish Laboratory, University of Cambridge. 2Department of Physics, NUS.

High-performance polymer semiconducting heterostructure devices by nitrene-mediated photocrosslinking of alkyl side chains

R.Q. Png1, P.J. Chia1, J.C. Tang2, B. Liu1, S. Sivaramakrishnan1, M. Zhou1, S-H. Khong3, H. S. O. Chan2, J. H. Burroughes4, L.L. Chua1,2,3, R.H. Friend1,3, P.K.H. Ho1 Nature Materials 9 (2010) 152 Abstract

1Departments of Physics, and 2Chemistry, NUS. 3Cavendish Laboratory, University of Cambridge. 4Cambridge Display Technology Ltd.

Solution-processed conjugated polymer organic p-i-n light-emitting diodes with high built-in potential by solution- and solid-state doping

S. Sivaramakrishnan1, M. Zhou1, A. C. Kumar1, Z. Chen1, R.Q. Png1, L.L. Chua2,3, P.K.H. Ho1. Applied Physics Letters 95 (2009) 213303 Abstract

1Departments of Physics, and 2Chemistry, NUS. 3Cavendish Laboratory, University of Cambridge.

Direct spectroscopic evidence for a photodoping mechanism in polythiophene and poly(bithiophene-alt-thienothiophene) organic semiconductor thin films involving oxygen and sorbed moisture

J.M. Zhuo2, L.H. Zhao1, R.Q. Png1, L.Y. Wong1, P.J. Chia1, J.C. Tang2, S. Sivaramakrishnan1, M. Zhou1, E.C.W. Ow1, S.J. Chua3, W.S. Sim2, L.L. Chua1,2, P.K.H. Ho1. Advanced Materials 21 (2009) 4747 Abstract

1Departments of Physics, and 2Chemistry, NUS. 3Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research).

Role of delta-hole-doped interfaces at ohmic contacts to organic semiconductor

M. Zhou1, L.L. Chua1,2, R.Q. Png1, C.K. Yong1, S. Sivaramakrishnan1, P.J. Chia1, A.T.S. Wee1, R.H. Friend1,3, P.K.H. Ho1. Physical Review Letters 103 (2009) 036601 Abstract

1Departments of Physics, and 2Chemistry, NUS. 3Cavendish Laboratory, University of Cambridge.

All-solution based device engineering of multilayer polymeric photodiodes: Minimizing dark current

P.E. Keivanidis1, S-H. Khong1, P.K.H. Ho2, N.C. Greenham1, R.H. Friend1,2 Applied Physics Letters 94 (2009) 173303 Abstract

1Cavendish Laboratory, University of Cambridge. 2Department of Physics, NUS.

Direct evidence for the role of the madelung potential in determining the work function of doped organic semiconductors

P.J. Chia1, S. Sivaramakrishnan1,M. Zhou1, R.Q. Png1, L.L. Chua1,2, R.H. Friend1,3, P.K.H. Ho1Physical Review Letters 102 (2009)096602 Abstract

1Departments of Physics, and 2Chemistry, NUS.3Cavendish Laboratory, University of Cambridge.

Optical modeling of the plasmon band of monolayer-protected nanometal clusters in pure and in polymer matrix thin films as a function of heat treatment

S. Sivaramakrishnan1, B. T. Anto1, P.K.H. Ho1 Applied Physics Letters 94 (2009) 091909 Abstract

1Department of Physics, NUS.

Direct evidence for delocalization of charge carriers at the Fermi level in a doped conducting polymer

J.M. Zhuo1,2, LH. Zhao2, P.J. Chia2, W.S. Sim1, R.H. Friend2,3, P.K.H. Ho2 Physical Review Letters 100 (2008) 186601 Abstract

1Departments of Physics, and 2Chemistry, NUS. 3Cavendish Laboratory, University of Cambridge.

Polyfluorene-based light-emitting diodes with an azide photocross-linked poly(3,4-ethylene dioxythiophene):(polystyrene sulfonic acid) hole-injecting layer

G. Winroth2, G. Latini2, D. Gredgington2, L.Y. Wong1, L.L. Chua1, P.K.H. Ho1, F. Cacialli2 Applied Physics Letters 92 (2008) 103308 Abstract

1Department of Physics, NUS. 2Department of Physics and Astronomy and London Centre for Nanotechnology, University College London.

Robust reproducible large-area molecular rectifier junctions

H.J. Che1,2, P.J. Chia1, L.L. Chua1, S. Sivaramakrishnan1, J.C. Tang2, A.T.S. Wee1, H.S.O. Chan2, P.K.H. Ho1 Applied Physics Letters 92 (2008) 253503 Abstract

1Departments of Physics, and 2Chemistry, NUS.

Chemical reversability of the electrical dedoping of conducting polymers: An organic chemically erasable programmable read-only memory

P.J. Chia1,2, Y.C. Yeo2, J.H. Burroughes3, R.H. Friend1,4, P.K.H. Ho Applied Physics Letters 93 (2008) 033314 Abstract

1Departments of Physics, and 2Electrical and Computer Engineering, NUS. 3Cambridge Display Technology Ltd. 4Cavendish Laboratory, Department of Physics, University of Cambridge.

Band-like transport in surface-functionalized highly solution-processable graphene nanosheets

S.Wang1, P.J. Chia1, L.L. Chua1, L.H. Zhao1, R.Q. Png1, S. Sivaramakrishnan1, M. Zhou1, R.G.S. Goh1, R.H. Friend1,2, A.T.S. Wee1, P.K.H. Ho1 Advanced Materials 20 (2008) 3440 Abstract

1Department of Physics, NUS. 2Cavendish Laboratory, University of Cambridge.

Deoxidation of graphene oxide nanosheets to extended graphenites by “unzipping” elimination

L.L. Chua1,2, S. Wang1, P.J. Chia1, L. Chen1, L.H. Zhao1, W. Chen1, A.T.S. Wee1 and P.K.H. Ho1 The Journal of Chemical Physics 129 (2008)114702 Abstract

1Departments of Physics, and 2Chemistry, NUS.

Solvent effects and multiple aggregate states in high-mobility organic field-effect transistors based on poly(bithiophene-alt-thienothiophene)

S. Wang1, J.C. Tang2, L.H. Zhao1, R.Q. Png1, L. Y. Wong1, P.J. Chia1, H.S.O. Chan2, P.K.H. Ho1, L.L.Chua1,2 Applied Physics Letters 93 (2008) 162103 Abstract

1Departments of Physics, and 2Chemistry, NUS.

Impact of self-assembled monolayer on low frequency noise of organic thin film transistors

K. Lin1, S. L. Dolmanan1, L. Shen1, C. Vijila1, S.J. Chua1, R.Q. Png2, P.J. Chia2, L.L.Chua2, P.K.H. Ho2 Applied Physics Letters 93 (2008) 153507 Abstract

1Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research). 2Department of Physics, NUS.

Controlled insulator-to-metal transformation in printable polymer composites with nanometal clusters

S. Sivaramakrishnan1, P.J. Chia1,2, Y. C. Yeo2, L.L. Chua1 and P.K.H. Ho1 Nature Materials 6 (2007) 149 Abstract

1Departments of Physics, and 2Electrical and Computer Engineering, NUS.

Solvent effects on chain orientation and interchain pi -interaction in conjugated polymer thin films: direct measurements of the air and substrate interfaces by near-edge X-ray absorption spectroscopy

P.K.H. Ho1, L.L. Chua1,2, M. Dipankar1, X. Gao1, D. Qi1, A.T.S. Wee1, J. F. Chang2 and R.H. Friend2 Advanced Materials 19 (2007) 215 Abstract

1Department of Physics, NUS. 2Cavendish Laboratory, University of Cambridge.

Electromigration of the conducting polymer in organic semiconductor devices and its stabilization by cross-linking

R.Q. Png1,2, P.J. Chia1,3, S. Sivaramakrishnan1, L.Y. Wong1, M. Zhou1, L.L. Chua1 and P.K.H. Ho1 Applied Physics Letters 91 (2007) 013511 Abstract

1Departments of Physics, and 2Materials Science, 3Electrical and Computer Engineering, NUS.

General photo-patterning of polyelectrolyte thin films via efficient ionic bis(fluorinated phenyl azide) photo-crosslinkers and their post-deposition modification

S.H. Khong, S. Sivaramakrishnan, R.Q. Png, L.Y. Wong, P.J. Chia, L.L. Chua and P.K.H. Ho Advanced Functional Materials 17 (2007) 2490 Abstract

Department of Physics, NUS.

Injection-induced de-doping in a conducting polymer during device operation: Asymmetry in the hole injection and extraction rates

P.J. Chia1,3, L.L. Chua1, S.Sivaramakrishnan1, J.M. Zhuo1,2, L.H. Zhao1, W.S. Sim2, Y.C. Yeo3, P.K.H. Ho1 Advanced Materials 19 (2007) 4202 Abstract

1Departments of Physics, 2Chemistry, and 3Electrical and Computer Engineering, NUS.

Large damage threshold and small electron escape depth in X-ray absorption spectroscopy of a conjugated polymer thin film

L.L. Chua, M. Dipankar, S. Sivaramakrishnan, X. Gao, D. Qi, A.T.S. Wee and P.K.H. Ho Langmuir 22 (2006) 8587 Abstract

Department of Physics, NUS.

General observation of n-type field-effect behaviour in organic semiconductors

L.L. Chua1,2, J. Zaumseil1, J.F. Chang1, E.C.W. Ou3, P.K.H. Ho1, H. Sirringhaus1, R.H. Friend1 Nature 434 (2005) 194 Abstract

1Cavendish Laboratory, Department of Physics, University of Cambridge. 2Department of Physics, NUS. 3Institute of Materials Research and Engineering, A*STAR

Organic double-gate field-effect transistors: Logic-AND operation

L.L. Chua1,2, R.H. Friend1 and P.K.H. Ho2 Applied Physics Letters 87 (2005) 253512 Abstract

1Cavendish Laboratory, Department of Physics, University of Cambridge. 2Department of Physics, NUS

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