Electron Transport Properties of a Carotene Molecule in a Metal−(Single Molecule)−Metal Junction

Citations Over TimeTop 1% of 2003 papers

Abstract

Using a recently developed method for tethering gold contacts to single molecules, we have measured current versus voltage (I−V) data for single carotenedithiol molecules with a total length of 28 carbons (18 in the conjugated alkene chain). The molecules are inserted into a docosanethiol monolayer (C22H45SH) on Au(111), and a Au nanoparticle is tethered to each molecule via the protruding thiol group. Electrical contact is made by placing a gold-coated AFM probe in contact with the nanoparticle. The I−V curves are relatively insensitive to contact probe force and cluster around integer multiples of a fundamental curve, suggesting that members of the smallest set correspond to data obtained from a single molecule. First principles calculations based on tunnel transport yield results that are remarkably close (within a factor of 4) to the measured data. The remaining small discrepancy can be well accounted for by taking account of the effects of charging caused by a probe-to-gold particle contact resistance. Thus, it appears that electron tunneling dominates transport even in this 3-nm-long molecule. The carotenoid is a better conductor than a saturated n-alkane of equivalent length by a very large factor and is significantly more conductive than 2,5-di(phenylethynyl-4'-thioacetyl)benzene, another candidate "molecular wire".

Related Papers

• → Availability of Carotene from Carrots and further Observations on Human Requirements for Vitamin A and Carotene(1947)13 cited
• → 1,2‐Epoxycarotenoids. Synthesis of the 1′,2′‐Epoxides of β,ψ‐ and ε,ψ‐Carotene (= γ‐ and δ‐Carotene, respectively)(1980)6 cited
• → ABSORPTION OF CAROTENE IN MAN AS OBSERVED FROM THE INCREASE OF SERUM VITAMIN A AND CAROTENE LEVELS(1960)2 cited
• 매운 맛 선호도가 한국 여대생의 β - Carotene 섭취와 혈청수준에 미치는 영향(1995)
• Determination and Analysis of β-Carotene in Different Varieties Carrots(2007)