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Organic Solar Cells: Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in PTB7:PC 71 BM Solar Cells (Adv. Energy Mater. 1/2013)
Author(s) -
Collins Brian A.,
Li Zhe,
Tumbleston John R.,
Gann Eliot,
McNeill Christopher R.,
Ade Harald
Publication year - 2013
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201370001
Subject(s) - materials science , agglomerate , organic solar cell , fullerene , nanoscopic scale , quantum efficiency , polymer solar cell , scattering , energy conversion efficiency , exciton , optoelectronics , polymer , chemical engineering , nanotechnology , optics , composite material , organic chemistry , physics , condensed matter physics , chemistry , engineering
The front cover represents the morphology and resulting device dynamics in organic solar cell blend films of PTB7 and PC 71 BM, as revealed by combined resonant X‐ray scattering and microscopy. Harald Ade and co‐workers find on page 65 that the fullerene molecules (red) are miscible in the polymer (blue) up to 30 wt.%, above which they begin to agglomerate (bottom). This agglomeration is important for the optoelectronic processes within the device, but the agglomerates must be kept to small sizes by the solvent processing additive diiodooctane (DIO). Correlation of this morphology with the spectrally resolved quantum efficiency shows that the yellow excitons created upon photoabsorption must arrive at the agglomerate interface for charge separation to occur. The blue electrons and green holes can then percolate through appropriate molecules in the mixed matrix to the electrodes for harvesting of electrical energy.