相关论文: Efficient charge separation in organic photovoltai…
We consider a simple model for the geminate electron-hole separation process in organic photovoltaic cells, in order to illustrate the influence of dimensionality of conducting channels on the efficiency of the process. The Miller-Abrahams…
The mechanism of electron-hole separation in organic solar cells is currently hotly debated. Recent experimental work suggests that these charges can separate on extremely short timescales (<100 fs). This can be understood in terms of…
Electron-hole pairs in organic photovoltaics dissociate efficiently despite their Coulomb-binding energy exceeding thermal energy at room temperature. The electronic states involved in charge separation couple to structured vibrational…
In organic photovoltaics, the mechanism by which free electrons and holes are generated overcoming the Coulomb attraction is a currently much debated topic. To elucidate this mechanism at a molecular level, we carried out a combined…
Organic/inorganic hybrid systems offer great potential for novel solar cell design combining the tunability of organic chromophore absorption properties with high charge carrier mobilities of inorganic semiconductors. However, often such…
The electron-hole pair created via photon absorption in organic photoconversion systems must overcome the Coulomb attraction to achieve long-range charge separation. We show that this process is facilitated through the formation of excited,…
Although organic heterojunctions can separate charges with near-unity efficiency and on a sub-picosecond timescale, the full details of the charge-separation process remain unclear. In typical models, the Coulomb binding between the…
The high efficiency of charge generation within organic photovoltaic blends apparently contrasts with the strong "classical" attraction between newly formed electron-hole pairs. Several factors have been identified as possible facilitators…
The separation of photogenerated polaron pairs in organic bulk heterojunction solar cells is the intermediate but crucial step between exciton dissociation and charge transport to the electrodes. In state-of-the-art devices, above 80% of…
Organic photovoltaics (OPVs) are promising candidates for solar-energy conversion, with device efficiencies continuing to increase. However, the precise mechanism of how charges separate in OPVs is not well understood because low dielectric…
Organic solar cells (OSCs) based on non-fullerene acceptors can show high charge generation yields despite near-zero donor-acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and…
Organic solar cells must separate strongly bound electron-hole pairs into free charges. This is achieved at interfaces between electron donor and acceptor organic semiconductors. The most popular electron acceptor is the fullerene…
This work presents a novel theoretical description of the non-equilibrium thermodynamics of charge separation process in organic solar cells (OSCs). Using the theory of stochastic thermodynamics, we connect the phonon-assisted dynamics and…
Charge separation is a critical process for achieving high efficiencies in organic photovoltaic cells. The initial tightly bound excitonic electron-hole pair has to dissociate fast enough in order to avoid photocurrent generation and thus…
Hot-carrier solar cells are envisioned to utilize energy filtering to extract power from photogenerated electron-hole pairs before they thermalize with the lattice, and thus potentially offer higher power conversion efficiency compared to…
The ultrafast dynamics of photon-to-charge conversion in an organic light harvesting system is studied by femtosecond time-resolved X-ray photoemission spectroscopy (TR-XPS) at the free-electron laser FLASH. This novel experimental…
A one-dimensional many-body model is established to mimic the charge distribution and dynamics in nonfullerene organic solar cells. Two essential issues are taken into account in the model: The alternating donor and acceptor structure and…
In organic solar cells, photogenerated singlet excitons form charge transfer (CT) complexes, which subsequently split into free charge carriers. Here, we consider the contributions of excess energy and molecular quadrupole moments to the…
Hot-carrier solar cells use the photon excess energy, that is, the energy exceeding the absorber bandgap, to do additional work. These devices have the potential to beat the upper limit for the photovoltaic power conversion efficiency set…
Control of the band-edge offsets at heterojunctions between organic semiconductors allows efficient operation of either photovoltaic or light-emitting diodes. We investigate systems where the exciton is marginally stable against charge…