Thermoelectric properties of oligoglycine molecular wires. Issue 8 (11th January 2019)

• Record Type: Journal Article
• Authors: Hou, Songjun; Wu, Qingqing; Sadeghi, Hatef; Lambert, Colin J.
• Is Part Of: Nanoscale. Volume 11:Issue 8(2019)
• Page Start: 3567
• Page End: 3573
• Publication Date: 2019-01-11
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c8nr08878k
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We have investigated the electrical and thermoelectrical properties of glycine chains with and without cysteine terminal groups. Abstract : We have investigated the electrical and thermoelectrical properties of glycine chains with and without cysteine terminal groups. The electrical conductance of (Gly) n, (Gly) n Cys and Cys(Gly) n Cys molecules (where Gly, Cys represent glycine and cysteine and n = 1–3) was found to decay exponentially with length l as e − βl . Our results show that connecting the molecules to gold electrodes via the sulphur atom of the cysteine moiety leads to higher β factors of 1.57 Å −1 and 1.22 Å −1 for (Gly) n Cys and Cys(Gly) n Cys respectively, while β = 0.92 Å −1 for (Gly) n . We also find that replacing the peptide bond with a methylene group (–CH2 –) increases the conductance of (Gly)3 Cys. Furthermore, we find the (Gly)1 Cys and Cys(Gly)1 Cys systems show good thermoelectrical performance, because of their high Seebeck coefficients (∼0.2 mV K −1 ) induced by the sulphur of the cysteine(s). With the contributions of both electrons and phonons taken into consideration, a high figure of merit ZT = 0.8 is obtained for (Gly)1 Cys at room temperature, which increases further with increasing temperature, suggesting that peptide-based SAM junctions are promising candidates for thermoelectric energy harvesting.