John Ho

John Ho

Sudbury, Massachusetts, United States
3K followers 500+ connections

About

Investor/Entrepreneur/Intrapreneur with technical and business experience at leading…

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Experience

  • ven^x Graphic

    ven^x

    Boston, Massachusetts, United States

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    Berkeley, California, United States

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    Oakland, California, United States

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    Greater Boston Area

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    Toronto, Canada Area

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    North Carolina, United States

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    Greater Boston Area

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    Greater Boston Area

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    Greater Chicago Area

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    Greater Boston Area

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    Greater Boston Area

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    Greater Boston Area

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    Greater Boston Area

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    Greater Boston Area

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    Greater Boston Area

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    Greater Boston Area

Education

  • Massachusetts Institute of Technology Graphic

    Massachusetts Institute of Technology

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    Activities and Societies: MIT Ventureships -- Artaic (2007) Varsity Crew (1998-2002) Phi Delta Theta Fraternity Sigma Xi Engineering Society Eta Kappa Nu Honor Society Tau Beta Pi Honor Society MIT Sport TKD (2003 - Present)

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Volunteer Experience

  • Trustee, Advancement Chair

    The Wayside Inn Foundation

    - Present 4 years 1 month

    Arts and Culture

  • Chairman of the Board of Trustees

    Sierra and Tango Condominiums

    - 4 years 6 months

    329 condominium units, $2M operating budget, 7 member Board of Trustees

Publications

  • Ultra-Bright, Highly Efficient, Low Roll-off Inverted Quantum-Dot Light Emitting Devices (QLEDs)

    Society For Information Display, Digest of Technical Papers

    We report an ultra-bright, highly efficient, low roll-off, inverted quantum dot-based red light emitting device (QLED) using solution-processed zinc oxide nanoparticles and cesium carbonate films as the electron injection and hole blocking layers, respectively. Record luminance of 165,000 Cd/m2 has been obtained at a current density of 1000 mA/cm2 with a low driving voltage of 5.8 V for deep red device with CIE coordinates of (0.69, 0.31).

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  • QDs Generate Light for Next-Generation Displays

    Photonics Spectra

    Large color gamut and better color reproducibility will be highly desired features of displays in the near future. Quantum dots will be the down-conversion technology of choice, allowing LCD makers to cost-effectively reach and exceed 100 percent of the NTSC and Adobe RGB color standards while achieving maximum system efficiency.

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  • Quantum Dots: The Ultimate Down-Conversion Material for LCD Displays

    Society for Information Display, Digest of Technical Papers

    Assuming large color gamut and therefore better color reproducibility will be a highly desired feature of all displays as we look to the near future, we make the case in this paper that Quantum Dots (QDs) are currently the down-conversion technology of choice that will allow liquid crystal display (LCD) makers to cost-effectively reach and exceed 100% of the NTSC (National Television Standard Committee) standard while achieving maximum system efficiency. We will discuss in detail the numerous…

    Assuming large color gamut and therefore better color reproducibility will be a highly desired feature of all displays as we look to the near future, we make the case in this paper that Quantum Dots (QDs) are currently the down-conversion technology of choice that will allow liquid crystal display (LCD) makers to cost-effectively reach and exceed 100% of the NTSC (National Television Standard Committee) standard while achieving maximum system efficiency. We will discuss in detail the numerous fundamental advantages of QDs over phosphors, along with their scientific origins, and make the case that QDs are the ultimate light generating material for next-generation displays.

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  • Large Area, Few-Layer Graphene Films on Arbitrary Substrates by Chemical Vapor Deposition

    Nano Letters

    In this work we present a low cost and scalable technique, via ambient pressure chemical vapor deposition (CVD) on polycrystalline Ni films, to fabricate large area (∼cm2) films of single- to few-layer graphene and to transfer the films to nonspecific substrates. These films consist of regions of 1 to ∼12 graphene layers. Single- or bilayer regions can be up to 20 μm in lateral size. The films are continuous over the entire area and can be patterned lithographically or by prepatterning the…

    In this work we present a low cost and scalable technique, via ambient pressure chemical vapor deposition (CVD) on polycrystalline Ni films, to fabricate large area (∼cm2) films of single- to few-layer graphene and to transfer the films to nonspecific substrates. These films consist of regions of 1 to ∼12 graphene layers. Single- or bilayer regions can be up to 20 μm in lateral size. The films are continuous over the entire area and can be patterned lithographically or by prepatterning the underlying Ni film. The transparency, conductivity, and ambipolar transfer characteristics of the films suggest their potential as another materials candidate for electronics and opto-electronic applications.

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  • Heterojunction Photodetector consisting of Metal-oxide and colloidal Quantum-dot thin Films

    Applied Physics Letters

    We demonstrate a heterojunction photodetector of lateral geometry that utilizes an evaporated film of the hole-transporting molecular material N,N′N,N′-bis(3-methylphenyl)-N,N′N,N′-bis(phenyl)-9,9-spirobifluorene (spiro-TPD) as a charge transport layer and that is sensitized across visible wavelengths by a thin film of colloidal CdSe nanocrystal quantum dots (QDs). High photon-to-electron quantum conversion efficiencies are obtained at room temperature as a result of photoconductive gain. With…

    We demonstrate a heterojunction photodetector of lateral geometry that utilizes an evaporated film of the hole-transporting molecular material N,N′N,N′-bis(3-methylphenyl)-N,N′N,N′-bis(phenyl)-9,9-spirobifluorene (spiro-TPD) as a charge transport layer and that is sensitized across visible wavelengths by a thin film of colloidal CdSe nanocrystal quantum dots (QDs). High photon-to-electron quantum conversion efficiencies are obtained at room temperature as a result of photoconductive gain. With an electric field of 3.0×105 V/cm3.0×105 V/cm applied across the electrodes, we measure the external quantum efficiency at the first QD absorption peak (at wavelength λ=590 nmλ=590 nm) to be 13%, corresponding to an internal quantum efficiency of approximately 80%. The operating mechanism of these devices is discussed, noting that the optical response is dominated by the QD absorption spectrum while the charge transport nearly exclusively takes place in the spiro-TPD.

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  • Lateral organic bilayer heterojunction photoconductors

    Applied Physics Letters

    We demonstrate a two-terminal, lateral organic bilayer photoconductor that generates an external quantum efficiency of (12±1)%(12±1)%, with an internal quantum efficiency of (140±2)%(140±2)% indicative of photon-to-electron conversion gain. The photoconductor incorporates a heterojunction between N,N′N,N′-bis(3-methylphenyl)-N,N′N,N′-diphenyl-1,1′1,1′-biphenyl-4,4′4,4′-diamine (TPD) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). Excitons generated with photoexcitation of PTCBI…

    We demonstrate a two-terminal, lateral organic bilayer photoconductor that generates an external quantum efficiency of (12±1)%(12±1)%, with an internal quantum efficiency of (140±2)%(140±2)% indicative of photon-to-electron conversion gain. The photoconductor incorporates a heterojunction between N,N′N,N′-bis(3-methylphenyl)-N,N′N,N′-diphenyl-1,1′1,1′-biphenyl-4,4′4,4′-diamine (TPD) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). Excitons generated with photoexcitation of PTCBI dissociate at the PTCBI/TPD interface and raise the charge carrier concentration in TPD, increasing device conductance. The exposed top surface enables interaction with chemical analytes in the environment, motivating the use of the photoconductor as a chemical sensor that transduces chemical signals into amplified changes in the electrical response.

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  • Solid-State Chemosensitive Organic Devices for Vapor-Phase Detection

    Springer, Berlin, Heidelberg

Patents

  • High Efficiency Multi-layer Photovoltaic Devices

    Issued US 8525022 B2

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Languages

  • French

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  • Mandarin

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  • Cantonese

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