Abstract :
Photovoltaic devices made from M-phthalocyanine and fullerene have been fabricated and characterized by current–voltage response,
lateral time-of-flight photoconductivity, UV-visible absorption and scanning electron microscopy. The effect of varying the central moiety
on the photovoltaic performance is examined, and demonstrates that the monovalent and divalent phthalocyanines tend to yield
higher efficiencies in blended structures, whereas the trivalent and tetravalent phthalocyanines tend to yield higher efficiencies in a bilayer
structure. The apparent reason for the disparity is the measured decrease in the hole transport efficiency in trivalent and tetravalent
phthalocyanine upon blending with C60. Furthermore, the open circuit voltages of M-phthalocyanine/fullerene solar cells are grouped
together according to the valency of the central moiety.
2012 Elsevier Ltd. All rights reserved
