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Correlation Between Structural and Optical Properties of Composite Polymer/Fullerene Films for Organic Solar Cells
Author(s) -
Erb T.,
Zhokhavets U.,
Gobsch G.,
Raleva S.,
Stühn B.,
Schilinsky P.,
Waldauf C.,
Brabec C. J.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200400521
Subject(s) - materials science , crystallinity , photocurrent , crystallite , organic solar cell , fullerene , annealing (glass) , polymer solar cell , thin film , chemical engineering , photoconductivity , solar cell , polymer , absorption (acoustics) , composite material , optoelectronics , nanotechnology , organic chemistry , chemistry , engineering , metallurgy
We investigate thin poly(3‐hexylthiophene‐2,5‐diyl)/[6,6]‐phenyl C 61 butyric acid methyl ester (P3HT/PCBM) films, which are widely used as active layers in plastic solar cells. Their structural properties are studied by grazing‐incidence X‐ray diffraction (XRD). The size and the orientation of crystalline P3HT nanodomains within the films are determined. PCBM crystallites are not detected in thin films by XRD. Upon annealing, the P3HT crystallinity increases, leading to an increase in the optical absorption and spectral photocurrent in the low‐photon‐energy region. As a consequence, the efficiency of P3HT/PCBM solar cells is significantly increased. A direct relation between efficiency and P3HT crystallinity is demonstrated.