| Summary: | 碩士 === 國立東華大學 === 物理學系 === 100 === Thermoelectric materials are very important in green energy development, but they have not been widely applied because of low thermopower conversion efficiency. In recent years, many scientists began to study thermoelectric properties of molecular. They discovered that some molecules may have better Seebeck coefficients than conventional conductors. Therefore, some molecules have considerable potential on thermoelectric development and applications. However, because of the difficulties to measure and to apply a single molecule, we modify the molecules on gold nanoparticles and form assemble films to study the Seebeck coefficient and Power factor of the films. That provide the thermoelectric properties of the molecules. In the work, we used 11-Mercaptoundecanoic acid (MUA), 8-mercaptooctanoic acid (MOA), 6-mercaptohexanoic acid (MHA), 3-Mercaptopropionic acid (MPA), 6-Mercapto-1-hexanol (MCH) and Heme B molecules to modify gold nanoparticles. From our experimental results, we found that in the sample of MPA, MHA, MOA and MUA molecules with longer carbon chain have higher Seebeck coefficients. And in regard to MOA, MUA, MCH and Heme B molecule films, their Seebeck coefficient are much higher than ordinary metals. Especially, the Seebeck coefficient of Heme B sample is as high as -5.5 × 103 μV/K. We also calculated the power factor of samples and found that MPA sample has lower Seebeck coefficient which is -1.6 × 101 μV/K, however, its resistivity is very low, so the Power factor can reached 2.8 × 10-1 μW/K2-m.
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