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Title: Enhancing photo-reduction quantum efficiency using quasi-type II core/shell quantum dots

Journal Article · · Chemical Science
DOI:https://doi.org/10.1039/c6sc00192k· OSTI ID:1624935
 [1];  [2];  [2];  [2];  [2];  [3];  [2]
  1. Emory Univ., Atlanta, GA (United States). Dept. of Chemistry; Xiamen Univ. (China). State Key Lab. of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Dept. of Chemistry
  2. Emory Univ., Atlanta, GA (United States). Dept. of Chemistry
  3. Xiamen Univ. (China). State Key Lab. of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Dept. of Chemistry
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Quantum confined semiconductor nanocrystals have emerged as a new class of materials for light harvesting and charge separation applications due to the ability to control their properties through rational design of their size, shape and composition. We report here a study of enhancing the quantum yield of methyl viologen (MV2+) photoreduction using colloidal quasi-type II CdSe/CdS core/shell quantum dots (QDs). The steady-state quantum yield of MV+c radical generation, in the presence of thiols as sacrificial donors, increased monotonically with the CdS shell thickness within the studied thickness regime (0–4.7 CdS monolayers). Using ultrafast transient absorption and time-resolved photoluminescence decay spectroscopy, we found that both the rates of electron transfer from the QD to MV2+ and the subsequent charge recombination in QD+–MV+c complexes decreased exponentially with the shell thickness, consistent with calculated 1S electron and hole densities at the QD surfaces, respectively. Interestingly, the hole transfer rate remained relatively independent of shell thickness, likely due to a cancellation of the reduction of hole transfer coupling strength with the increased number of hole acceptor ligands on the QD surface at larger shell thickness. As a result, with increasing CdS shell thickness, the charge recombination loss decreases, enhancing the photoreduction quantum efficiency. This novel approach for improving photoreduction quantum efficiency should be applicable to many type II and quasi-type II core/shell quantum dots.

Research Organization:
Emory Univ., Atlanta, GA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Air Force Office of Scientific Research (AFOSR); National Science Foundation (NSF)
Grant/Contract Number:
FG02-07ER15906; FA9550-13-1-0020; CHE-0958205
OSTI ID:
1624935
Journal Information:
Chemical Science, Vol. 7, Issue 7; ISSN 2041-6520
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 29 works
Citation information provided by
Web of Science

References (44)

Experimental Determination of the Extinction Coefficient of CdTe, CdSe, and CdS Nanocrystals journal July 2003
Hot-Electron Transfer from Semiconductor Nanocrystals journal June 2010
Effect of Insulating Oxide Overlayers on Electron Injection Dynamics in Dye-Sensitized Nanocrystalline Thin Films journal March 2007
Multiple Exciton Collection in a Sensitized Photovoltaic System journal September 2010
Peak External Photocurrent Quantum Efficiency Exceeding 100% via MEG in a Quantum Dot Solar Cell journal December 2011
Efficiency of Hole Transfer from Photoexcited Quantum Dots to Covalently Linked Molecular Species journal January 2015
Near Unity Quantum Yield of Light-Driven Redox Mediator Reduction and Efficient H 2 Generation Using Colloidal Nanorod Heterostructures journal July 2012
Efficient hot-electron transfer by a plasmon-induced interfacial charge-transfer transition journal August 2015
Mapping the Optical Properties of CdSe/CdS Heterostructure Nanocrystals: The Effects of Core Size and Shell Thickness journal October 2009
Alkanethiolate Gold Cluster Molecules with Core Diameters from 1.5 to 5.2 nm:  Core and Monolayer Properties as a Function of Core Size journal January 1998
Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology journal April 2005
Controlling Charge Separation and Recombination Rates in CdSe/ZnS Type I Core−Shell Quantum Dots by Shell Thicknesses journal October 2010
Suppressed Auger Recombination in “Giant” Nanocrystals Boosts Optical Gain Performance journal October 2009
Size dependence of exciton fine structure in CdSe quantum dots journal June 1996
Simultaneous Determination of the Adsorption Constant and the Photoinduced Electron Transfer Rate for a Cds Quantum Dot–Viologen Complex journal July 2011
Ultrafast Electronic Delocalization in CdSe/CdS Quantum Rod Heterostructures journal November 2011
Spectral and Dynamical Properties of Multiexcitons in Semiconductor Nanocrystals journal May 2007
Photoelectrochemical pumping of enzymatic CO2 reduction journal May 1984
(CdSe)ZnS Core−Shell Quantum Dots: Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites journal November 1997
Ultrafast Electron Transfer at the Molecule-Semiconductor Nanoparticle Interface journal May 2005
Hole Removal Rate Limits Photodriven H 2 Generation Efficiency in CdS-Pt and CdSe/CdS-Pt Semiconductor Nanorod–Metal Tip Heterostructures journal May 2014
Auger-Assisted Electron Transfer from Photoexcited Semiconductor Quantum Dots journal February 2014
Hydrogen evolution from water induced by visible light mediated by redox catalysis journal October 1979
Wave Function Engineering for Ultrafast Charge Separation and Slow Charge Recombination in Type II Core/Shell Quantum Dots journal June 2011
Electron-transfer communication between a redox polymer matrix and an immobilized enzyme: activity of nitrate reductase in a viologen-acrylamide copolymer journal August 1990
Beyond Band Alignment: Hole Localization Driven Formation of Three Spatially Separated Long-Lived Exciton States in CdSe/CdS Nanorods journal July 2013
Poisson-Distributed Electron-Transfer Dynamics from Single Quantum Dots to C60 Molecules journal December 2010
Distance-Dependent Electron Transfer in DNA Hairpins journal August 1997
Experimental Determination of the Extinction Coefficient of CdTe, CdSe and CdS Nanocrystals. journal February 2004
Hole scavenger redox potentials determine quantum efficiency and stability of Pt-decorated CdS nanorods for photocatalytic hydrogen generation journal May 2012
Robust Photogeneration of H2 in Water Using Semiconductor Nanocrystals and a Nickel Catalyst journal November 2012
Large-Scale Synthesis of Nearly Monodisperse CdSe/CdS Core/Shell Nanocrystals Using Air-Stable Reagents via Successive Ion Layer Adsorption and Reaction journal October 2003
Measurement of the extinction coefficient of the methyl viologen cation radical and the efficiency of its formation by semiconductor photocatalysis journal July 1982
The Effect of the Charge-Separating Interface on Exciton Dynamics in Photocatalytic Colloidal Heteronanocrystals journal August 2012
The Role of Hole Localization in Sacrificial Hydrogen Production by Semiconductor–Metal Heterostructured Nanocrystals journal July 2011
Ultrafine and specific catalysts affording efficient hydrogen evolution from water under visible light illumination journal June 1981
Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology journal August 2005
Wave Function Engineering for Efficient Extraction of up to Nineteen Electrons from One CdSe/CdS Quasi-Type II Quantum Dot journal February 2012
Synthesis and Characterization of Strongly Luminescing ZnS-Capped CdSe Nanocrystals journal January 1996
Multiple Exciton Dissociation in CdSe Quantum Dots by Ultrafast Electron Transfer to Adsorbed Methylene Blue journal April 2010
Multiexciton Annihilation and Dissociation in Quantum Confined Semiconductor Nanocrystals journal November 2012
Breakdown of Volume Scaling in Auger Recombination in CdSe/CdS Heteronanocrystals: The Role of the Core−Shell Interface journal February 2011
Ultrafast Charge Separation in Multiexcited CdSe Quantum Dots Mediated by Adsorbed Electron Acceptors journal February 2009
Ultrafast exciton quenching by energy and electron transfer in colloidal CdSe nanosheet–Pt heterostructures journal January 2015

Cited By (7)

Direct Correlation of Excitonics with Efficiency in a Core-Shell Quantum Dot Solar Cell journal January 2018
In situ formation of nano-CdSe as a photocatalyst: cadmium ion-enhanced photochemical vapour generation directly from Se( vi ) journal January 2018
The electronic and optical properties of an exciton, biexciton and charged excitons in CdSe/CdTe-based multi-shell type-II quantum dot nanocrystals journal September 2019
Correlating Charge‐Carrier Dynamics with Efficiency in Quantum‐Dot Solar Cells: Can Excitonics Lead to Highly Efficient Devices? journal November 2018
Hot-electron transfer from the semiconductor domain to the metal domain in CdSe@CdS{Au} nano-heterostructures journal January 2017
Reversible ON/OFF switching of photoluminescence from CsPbX 3 quantum dots coated with silica using photochromic diarylethene journal January 2019
Ultrafast charge carrier dynamics in CdSe/V 2 O 5 core/shell quantum dots journal January 2019

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