ORGANIC SEMICONDUCTOR DEVICES FOR CHEMICAL SENSING AND BIO INTERFACES
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Date
2016-03-18
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Johns Hopkins University
Abstract
The scope of this work is to establish organic field effect transistors (OFET) as a viable platform for sensing and for interfacing between biological and electronic materials.
In section 1 we discuss our approaches and strategies for designing gas sensor platforms for ammonia and ethylene using the OFET platform. For ammonia sensor, we devised an organic field-effect transistor (OFET) structure with tris(pentafluorophenyl)borane (TPFB) as ammonia receptor. OFETs with this additive could detect concentrations of 450 ppb v/v, with a limit of detection of 350 ppb. For printable versions of ammonia sensors, we simplified the OFET structure by replacing the gate electrode and the dielectric deposition steps with the introduction of static charges on the back surface of the polyethylene terephthalate (PET) substrate by corona charging, a procedure that is adaptable to roll-to-roll processing. This technique considerably decreased the time and the cost of production.
For ethylene sensors, we developed an OFET platform with an organic semiconductor layer containing palladium particles as ethylene receptor. With this unique active sensing layer, we could sense concentration of 50-ppm v/v.
In section 2, we studied OSCs as candidates for developing bio interfaces. In the first part of this section we investigated OFETs as an electronic bio sensing platform. We designed an OFET-based biosensor with a new receptor–antibody-functionalized composite top dielectric layer consisting of a fluorinated polymer (CYTOP) and vapor-deposited hydrocarbon (tetratetracontane). Using glial fibrillary acidic protein (GFAP) as a model protein analyte, this sensor platform demonstrated significant selectivity and recognition of target protein even in concentrated non-target protein backgrounds.
In second part of section 2, we studied electrical properties of functionalized self-assembling nanowires using OFET structures. The effect of systematic changes in amino acid composition on the semiconducting/conducting functionality of the nanostructures was analyzed. The study shows that these self-assembling peptides can be used successfully to transmit electronic signals over biologically relevant distances. This library of nanowires should be instrumental in electrically manipulating and stimulating cells for bioengineering purposes.
The strategies and the results discussed here open new pathways for the future development of these areas.
Readers
Professor Howard E. Katz (Advisor)
Professor John D. Tovar (Chair of the defense Committee)
Description
Keywords
Sensors, Organic field effect transistor, Nanowires, Biointerfaces, Ammonia, Ethylene, Glial fibrillary acidic protien