Biomedical subjects

Yuning Li

Publications and source records attributed to Yuning Li.

4 recordsLinked to original sources

PubMed2006

Enabling gate dielectric design for all solution-processed, high-performance, flexible organic thin-film transistors.

A novel solution-processed, compositionally and structurally stable dual-layer gate dielectric composed of a UV-cured poly(4-vinyl phenol)-co-poly(methyl methacrylate) bottom layer and a thermally cross-linked poly(methyl silsesquioxane) top layer for organic thin-film transistors is described. This gate dielectric design, coupled with compatible solution-processable semiconductor and conductor materials, has enabled fabrication of all solution-processed, high-performance organic thin-film transistors on flexible substrates. High field-effect mobility and current on/off ratio, together with other desirable transistor properties, are demonstrated.

Journal Article↗

PubMed2006

Printed silver ohmic contacts for high-mobility organic thin-film transistors.

Oleic acid-stabilized silver nanoparticles prepared by a facile synthesis afforded highly conductive elements upon proper annealing. Regioregular polythiophene-based thin-film transistors (OTFTs) using source/drain electrodes prepared from these silver nanoparticles provided excellent field-effect characteristics, despite a significant difference between the work function of silver and the HOMO of polythiophene semiconductor. This was attributable to conductive doping of the semiconductor interface by residual oleic acid or its thermally transformed derivative from the silver electrodes, thus enabling ohmic contact formation. This is in sharp contrast to the OTFTs with silver electrodes fabricated from both vacuum deposition and oleylamine-stabilized silver nanoparticles, which exhibited markedly lower mobility and current on/off ratio, a consequence of energetic mismatch of the electrode/semiconductor pairs.

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PubMed2005

Facile synthesis of silver nanoparticles useful for fabrication of high-conductivity elements for printed electronics.

A facile synthesis of stable silver nanoparticles having a particle size of <10 nm is described. The synthesis involved reduction of silver acetate with a substituted hydrazine, such as PhNHNH2, in the presence of a 1-alkylamine, such as C16H33NH2, in toluene at 25-60 degrees C. Spin-coated thin films or printed electronic features of alkylamine-stabilized silver nanoparticles could be easily converted at 120-160 degrees C into highly conductive films or elements with conductivity of 2-4 x 104 S cm-1. Organic thin-film transistors with printed silver source/drain electrodes of this nature exhibited field-effect transistor properties which are similar to those of the devices using vacuum-deposited silver electrodes.

Journal Article↗

PubMed2005

Indolo[3,2-b]carbazole-based thin-film transistors with high mobility and stability.

Proper functionalization of indolo[3,2-b]carbazole led to a new class of high-performance organic semiconductors suitable for organic thin-film transistor (OTFT) applications. While 5,11-diaryl-substituted indolo[3,2-b]carbazoles without long alkyl side chains provided amorphous thin films upon vacuum deposition, those with sufficiently long alkyl side chains such as 5,11-bis(4-octylphenyl)indolo[3,2-b]carbazole self-organized readily into highly crystalline layered structures under similar conditions. OTFTs using channel semiconductors of this nature exhibited excellent field-effect properties, with mobility up to 0.12 cm(2) V(-1) s(-1) and current on/off ratio to 10(7). As this class of organic semiconductors has relatively low HOMO levels and large band gaps, they also displayed good environmental stability even with prolonged exposure to amber light, an appealing characteristic for OTFT applications.

Journal Article↗