Efficient Photosynthesis of Organics from Aqueous Bicarbonate Ions by Quantum Dots Using Visible Light

Bhattacharyya, Biswajit and Simlandy, Amit Kumar and Chakraborty, Arunavo and Rajasekar, Guru Pratheep and Aetukuri, Nagaphani B and Mukherjee, Santanu and Pandey, Anshu (2018) Efficient Photosynthesis of Organics from Aqueous Bicarbonate Ions by Quantum Dots Using Visible Light. In: ACS ENERGY LETTERS, 3 (7). pp. 1508-1514.

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Abstract

We synthesized CuAlS2/ZnS quantum dots (QDs) composed of biocompatible, earth-abundant elements that can reduce salts of carbon dioxide under visible light. The use of an asymmetric morphology at a type-II CuAlS2/ZnS heterointerface balances multiple requirements of a photoredox agent by providing a low optical bandgap (similar to 1.5 eV), a large optical cross section (>10(-16) cm(2) above 1.8 eV), spatial proximity of both semiconductor components to the surface, as well as photochemical stability. CuAlS2/ZnS QDs thus have an unprecedented photochemical activity in terms of reducing carbon dioxide in the form of aqueous sodium bicarbonate under visible light, without the need for a cocatalyst, promoter, or sacrificial reagent while maintaining large turnover numbers in excess of 7 x 10(4) per QD. Devices based on these QDs exhibit energy conversion efficiencies as high as 20.2 +/- 0.2%. These observations are rationalized through our spectroscopic studies that show short 550 fs electron dwell times in these structures. The high energy efficiency and the environmentally friendly composition of these materials suggest a future role in solar light harvesting.

Item Type:	Journal Article
Publication:	ACS ENERGY LETTERS
Publisher:	AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Additional Information:	Copyright of this article belong to AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Organic Chemistry Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	10 Aug 2018 16:08
Last Modified:	10 Aug 2018 16:08
URI:	http://eprints.iisc.ac.in/id/eprint/60405

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