| Summary: | 碩士 === 國立交通大學 === 奈米科技研究所 === 94 === Melanins belong to a family of pigmented biopolymers that occur widely in nature from plant, animal, to microbe. Their main function is to protect living organisms against UV radiation. Melanin is a strong antioxidant with free
radical scavenging activity, a strong heavy-metal chelator, a strong organic toxin absorber, and bio-compatibility; thus, it serves as a natural guardian against hostile chemical and heavy-metal environments. Melanin was extracted from tea in large and economic scale. We also characterized the conductivity, composition, and physical properties of melanins by SEM, EDS, OM, and FTIR.
An amorphous thin film of melanin exhibited semiconductor properties.Iodine-doping enhanced this conductivity. Our results indicated that melanin extracted from tea is an abundant resource of low-toxic and natural material for
low temperature processing of electronic devices.
Melanin thin film also presented a second switching voltage different from previous reports. Organic thin film transistors (OTFTs) based on semiconducting tea melanin films were fabricated, which acted as switch devices. Tea melanin OTFTs showed a p-channel enhancement property.
Oxidation enhanced tea melanin films conductivity. The conductive properties for the tea melanin films might provide further insight into the biological
function of tea melanin devices. Tea melanin OTFTs showed a p-channel enhancement property.Oxidation enhanced tea melanin films conductivity. The conductive properties
for the tea melanin films might provide further insight into the biological function of tea melanin.
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