89 research outputs found
Comment on "Interface state recombination in organic solar cells"
In a recent paper, Street et al. [Phys. Rev. B 81, 205307 (2010)] propose
first order recombination due to interface states to be the dominant loss
mechanism in organic bulk heterojunction solar cells, based on steady-state
current--voltage characteristics. By applying macroscopic simulations, we found
that under typical solar cell conditions, monomolecular or bimolecular
recombination cannot be inferred from the slope of the light intensity
dependent photocurrent. In addition, we discuss the validity of calculating a
mobility--lifetime product from steady-state measurements. We conclude that the
experimental technique applied by Street et al. is not sufficient to
unambiguously determine the loss mechanism.Comment: 4 pages, 2 figures. Corrected Eqns. (2) and (4): 1/... was missin
Investigation of electronic trap states in organic photovoltaic materials by current-based deep level transient spectroscopy
Current-based deep level transient spectroscopy was used to study trap states
in poly(3- hexylthiophene-2,5-diyl) (P3HT), [6,6]-phenyl-C61 butyric acid
methyl ester (PCBM) and P3HT:PCBM blend. The obtained spectra showed traps of
87 meV activation energy in pure P3HT and 21 meV for PCBM. The blend shows a
complex emission rate spectrum consisting of several different emission rate
bands in the range of (0.1-30) s^-1, yielding activation energies between about
30 meV and 160 meV.Comment: 4 pages, 3 figure
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