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Ultrafast transient absorption spectroscopy is used to study charge transfer dynamics in hybrid films composed of the low band gap polymer PCPDTBT and CdSe quantum dots capped with tert-butylthiol ligands. By selectively exciting the polymer, a spectral signature for electrons on the quantum dots appears on ultrafast time scales (≲ 65 fs), which indicates ultrafast electron transfer. From this timescale, the coupling between the polymer chains and the quantum dots is estimated to be J ≳ 17 meV. The reduced quantum dot acceptors exhibit an unambiguous spectral bleach signature, whose amplitude allows for the first direct calculation of the absolute electron transfer yield in a hybrid solar cell (82 ± 5%). We also show that a limitation of the hybrid system is rapid and measurable geminate recombination due to the small separation of the initial charge pair. The fast recombination is consistent with the internal quantum efficiency of the corresponding solar cell. We therefore have identified and quantified a main loss mechanism in this type of third generation solar cell.
This article was published in the following journal.
Name: Journal of the American Chemical Society
Fluorescence quenching studies through steady-state and time resolved measurements are inadequate to quantify the bi-molecular electron transfer rate in bulk homogeneous solution due to constrain put ...
Charge transfer (CT) at donor (D)/acceptor (A) interfaces is central to the functioning of photovoltaic and light-emitting devices. Understanding and controlling this process on the molecular level ha...
Thermal modeling and numerical simulations have been performed to describe the ultrafast thermal response of band gap materials upon optical excitation. A model was established by extending the conven...
Recent work has proposed that coherent effects impact ultrafast electron transfer reactions. Here we report studies using broadband pump probe and two-dimensional electronic spectroscopy of intramolec...
Addition of allylmagnesium reagents to an aliphatic aldehyde bearing a radical clock gave only addition products and no evidence of ring-opened products that would suggest single-electron-transfer rea...
The purpose of this study is to evaluate two types of embryo transfer procedure. The investigators will compare direct embryo transfer against afterloading embryo transfer.
The aim is to compare a new technique for assessing mechanical properties of large arteries: the Ultrafast echo with the reference technique, the echotracking. This will be done by studyin...
The purpose of this study is to determine whether the BOA(R)-Constricting IV Band is superior to standard methods for starting an IV.
To investigate the relationship between coronary heart disease risk factors and coronary artery calcification in middle age adults from the Muscatine Study. From 1992 through 1995, ultraf...
The purpose of this study is to correlate accurate fluoroscopic measurement of gastric band stoma diameter with patient symptoms for optimal band stoma adjustment. Administration of a bari...
A bacterial protein from Pseudomonas, Bordetella, or Alcaligenes which operates as an electron transfer unit associated with the cytochrome chain. The protein has a molecular weight of approximately 16,000, contains a single copper atom, is intensively blue, and has a fluorescence emission band centered at 308nm.
An autosomal recessive disorder of fatty acid oxidation, and branched chain amino acids (AMINO ACIDS, BRANCHED-CHAIN); LYSINE; and CHOLINE catabolism, that is due to defects in either subunit of ELECTRON TRANSFER FLAVOPROTEIN or its dehydrogenase, electron transfer flavoprotein-ubiquinone oxidoreductase (EC 126.96.36.199).
An electron transport chain complex that catalyzes the transfer of electrons from SUCCINATE to CYTOCHROME C. It includes ELECTRON TRANSPORT COMPLEX II and ELECTRON TRANSPORT COMPLEX III.
Cytochromes of the b group that have alpha-band absorption of 563-564 nm. They occur as subunits in MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX III.
Flavoproteins that serve as specific electron acceptors for a variety of DEHYDROGENASES. They participate in the transfer of electrons to a variety of redox acceptors that occur in the respiratory chain.