相关论文: Bipolar polaron pair recombination in P3HT/PCBM so…
Spin-dependent processes play a crucial role in organic electronic devices. Spin coherence can give rise to spin mixing due to a number of processes such as hyperfine coupling, and leads to a range of magnetic field effects. However, it is…
We propose a model to explain the reduced bimolecular recombination rate found in state-of-the-art bulk heterojunction solar cells. When compared to the Langevin recombination, the experimentally observed rate is one to four orders of…
The effect of exchange interactions within spin pairs on spin-dependent transport and recombination rates through localized states in semiconductors during coherent electron spin resonant excitation is studied theoretically. It is shown…
We report on the non-trivial field dependence of charge carrier recombination in an organic blend at low temperatures. A new microwave resonance technique for monitoring charge recombination in organic semiconductors at low temperatures is…
The ongoing depletion of fossil fuels has led to an intensive search for additional renewable energy sources. Solar-based technologies could provide sufficient energy to satisfy the global economic demands in the near future. Photovoltaic…
We have studied the role of spin-dependent processes on conductivity in polyfluorene (PFO) thin films by conducting continuous wave (c.w.) electrically detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K and 293 K…
Recently, much effort has been devoted to improve the efficiency of organic photovoltaic solar cells based on blends of donors and acceptors molecules in bulk heterojunction architecture. One of the major losses in organic photovoltaic…
We explore the magnetoresistance (MC) effect in an organic semiconductor device based on the magnetic field related bipolaron formation. By establishing a group of dynamic equations, we present the transition among spin-parallel,…
At low temperatures and high magnetic fields, electron and hole spins in an organic light-emitting diode (OLED) become polarized so that recombination preferentially forms molecular triplet excited-state species. For low device currents,…
Charge carrier recombination is studied in operational organic solar cells made from the polymer:fullerene system PCDTBT:PC71BM (poly[N-9"-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] :…
Suppressing charge recombination is key for organic solar cells to become commercial reality. However, there is still no conclusive picture of how recombination losses are influenced by the complex nanoscale morphology. Here, new insight is…
We report transient electron paramagnetic resonance (trEPR) measurements with sub-microsecond time resolution performed on a P3HT:PCBM blend at low temperature. The trEPR spectrum immediately following photoexcitation reveals signatures of…
The effect of dipolar and exchange interactions within pairs of paramagnetic electronic states on Pauli-blockade-controlled spin-dependent transport and recombination rates during magnetic resonant spin excitation is studied numerically…
The major loss mechanism of photogenerated polarons was investigated in P3HT:PCBM solar cells by the photo-CELIV technique. For pristine and annealed devices, we find that the experimental data can be explained by a bimolecular…
Materials containing high densities of exceptionally displaceable ions (e.g. perovskites) have extremely large ratios of their static to high-frequency dielectric constants, > 2. Large polarons form in such materials as their electronic…
Apparent recombination orders exceeding the value of two expected for bimolecular recombination have been reported for organic solar cells in various publications. Two prominent explanations are bimolecular losses with a carrier…
Theoretical treatment of the electron spin echo envelope modulation (ESEEM) spectra from polarons in a semiconducting $\pi$- conjugated polymer is presented. The contact hyperfine coupling and the dipolar interaction between the polaron and…
Here we describe a new high frequency/high field continuous wave and pulsed electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in…
The magnetoelectroluminescence of conjugated organic polymer films is widely accepted to arise from a polaron pair mechanism, but their magnetoconductance is less well understood. Here we derive a new relationship between the experimentally…
The power conversion efficiency of organic solar cells based on donor--acceptor blends is governed by an interplay of polaron pair dissociation and bimolecular polaron recombination. Both processes are strongly dependent on the charge…