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Thermoelectric properties of oligoglycine molecular wires. / Hou, S.; Wu, Q.; Sadeghi, H. et al.
In: Nanoscale, Vol. 11, No. 8, 28.02.2019, p. 3567-3573.Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Thermoelectric properties of oligoglycine molecular wires
AU - Hou, S.
AU - Wu, Q.
AU - Sadeghi, H.
AU - Lambert, C.J.
PY - 2019/2/28
Y1 - 2019/2/28
N2 - 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 (-CH 2 -) 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.
AB - 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 (-CH 2 -) 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.
KW - Energy harvesting
KW - Molecules
KW - Peptides
KW - Sulfur
KW - Electrical conductance
KW - Electrons and phonons
KW - High figure of merit ZT
KW - Increasing temperatures
KW - Methylene groups
KW - Molecular wires
KW - Thermoelectric energy
KW - Thermoelectric properties
KW - Amino acids
U2 - 10.1039/c8nr08878k
DO - 10.1039/c8nr08878k
M3 - Journal article
VL - 11
SP - 3567
EP - 3573
JO - Nanoscale
JF - Nanoscale
SN - 2040-3364
IS - 8
ER -