High field magneto-photocurrent in organic bulk hetero-junction photo-voltaic cells

Role of Contact Injection, Exciton Dissociation, and Recombination, Revealed through Voltage and Intensity Mapping of the Quantum Efficiency of Polymer:Fullerene Solar Cells

“…These three effectively determine the efficiency of converting excitons into free charge carriers and hence cannot be effectively separated using our data. To overcome this, we fix the value for the dissociation rate of CT-excitons into free carriers ( K cd = 8 × 10 9 s –1 ). , Through the fitting procedure, we find that the CT-exciton polaron annihilation can vary between 0.5 × 10 –9 and 1.5 × 10 –9 cm 3 s –1 and that for this range the quality of the fit is dependent on the ratio between K ct and K ct‑p . Having said the above, one should keep in mind that when we report that a given device has a relatively higher ratio, it could be due to a higher rate of exciton to CT-exciton, higher rate of CT-exciton to free carriers, or lower annihilation rate of CT-exciton by polarons.…”

Magnetic Field Modulation of Recombination Processes in Organic Photovoltaics

“…[5] When organic semiconducting devices are subjected to applied magnetic fields their behavior changes. These changes are termed magnetic field effects (MFEs) and are seen in the performance of organic electronic devices, including lightemitting diodes (LEDs), [6] and photovoltaic (PV) cells [7]. The reported effects include changes in current and light output in LEDs, [8], [9], and photocurrent in PVs.…”