TY - JOUR
T1 - Charge separation and recombination pathways in diblock dna hairpins
AU - Olshansky, Jacob H.
AU - Young, Ryan M.
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-FG02-99ER14999 (M.R.W.) The authors thank Professor Fred Lewis for fruitful discussions and Dr. Itai Schlesinger for assistance with sample preparation.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/2/21
Y1 - 2019/2/21
N2 - Achieving high-yielding photoinduced charge separation through the I-stacked bases of DNA is a critical requirement for realizing numerous DNA-based technologies. In the current work, we combine two strategies for achieving high-yield charge separation. First, a chromophore with a high driving force for charge injection, naphthalenediimide (NDI), is used because it generates hot carriers that enhance charge-Transfer rates. Second, a diblock DNA sequence is used with two or three adenines followed by a series of guanines to implement an energy landscape that accelerates charge separation while retarding charge recombination. The photoinduced dynamics of these NDI diblock oligomers with and without a terminal hole acceptor are probed by femtosecond transient absorption spectroscopy. The measured rate constants for various charge separation and recombination processes are interpreted within the context of a full kinetic model of these systems. We find that the A 2 and A 3 oligomers achieve similar charge separation yields (as high as 20-25%) for a given length, yet the critical recombination process that determines these yields occurs at different distances from the NDI chromophore and on different time scales. This type of analysis could be used to predict charge separation efficiencies in candidate DNA structures.
AB - Achieving high-yielding photoinduced charge separation through the I-stacked bases of DNA is a critical requirement for realizing numerous DNA-based technologies. In the current work, we combine two strategies for achieving high-yield charge separation. First, a chromophore with a high driving force for charge injection, naphthalenediimide (NDI), is used because it generates hot carriers that enhance charge-Transfer rates. Second, a diblock DNA sequence is used with two or three adenines followed by a series of guanines to implement an energy landscape that accelerates charge separation while retarding charge recombination. The photoinduced dynamics of these NDI diblock oligomers with and without a terminal hole acceptor are probed by femtosecond transient absorption spectroscopy. The measured rate constants for various charge separation and recombination processes are interpreted within the context of a full kinetic model of these systems. We find that the A 2 and A 3 oligomers achieve similar charge separation yields (as high as 20-25%) for a given length, yet the critical recombination process that determines these yields occurs at different distances from the NDI chromophore and on different time scales. This type of analysis could be used to predict charge separation efficiencies in candidate DNA structures.
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U2 - 10.1021/acs.jpcb.8b11782
DO - 10.1021/acs.jpcb.8b11782
M3 - Article
C2 - 30658529
AN - SCOPUS:85060809500
VL - 123
SP - 1545
EP - 1553
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 7
ER -