Journal
PHYSICAL REVIEW B
Volume 85, Issue 20, Pages -Publisher
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevB.85.205211
Keywords
-
Funding
- AFOSR [FA9550-09-1-0436]
Ask authors/readers for more resources
Prolonged x-ray exposure of bulk heterojunction organic solar cells induces deep trap states that are observed in measurements of the photocurrent spectral response. The density of induced trap states is proportional to the density of recombination centers as measured by the voltage dependence of the photocurrent, therefore identifying the traps as primary recombination centers. The states are reversible by thermal annealing to about 100 degrees C, which implies a metastable structural change with binding energy 1-1.2 eV. However, the annealing kinetics reveal three different annealing processes, although for defect states with essentially the same electronic character. Analysis of the radiation damage indicates that defects are formed by hydrogen release from C-H bonds due to electronic excitation by the energetic secondary electrons created by the x rays. Theoretical structure calculations of possible hydrogen-related defects find specific defect states that match the experimental observations and provide values for hydrogen migration energies that are consistent with the annealing kinetics. The effects of prolonged white light exposure are very similar to x-ray exposure, although the annealing kinetics are significantly different. Measurements of the spectral response with bias illumination provide information about the energy level of the localized states.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available