Direct Spectroscopic Evidence of Ultrafast Electron Transfer from a Low Band Gap Polymer to CdSe Quantum Dots in Hybrid Photovoltaic Thin Films.
Summary of "Direct Spectroscopic Evidence of Ultrafast Electron Transfer from a Low Band Gap Polymer to CdSe Quantum Dots in Hybrid Photovoltaic Thin Films."
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
The conversion of photoexcitations into charge carriers in organic solar cells is facilitated by the dissociation of excitons at the donor/acceptor interface. The ultrafast timescale of charge separat...
In recent years visible pump/mid-IR probe spectroscopy has established itself as a key technology to unravel structure-function relationships underlying the photo-dynamics of complex molecular systems...
A novel electron rich, tetrathiafulvalene fused zinc porphyrin, (TTF)4PZn, has been newly synthesized and characterized using spectral and electrochemical methods. In spite of the presence of eight t-...
Laser-triggered electron emission from sharp metal tips has been demonstrated in recent years as a high brightness, ultrafast electron source. Its possible applications range from ultrafast electron m...
Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, dir...
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...
Medical and Biotech [MESH] Definitions
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 188.8.131.52).
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.