EN
We present a method to fabricate binary organic donor and
acceptor blends exhibiting a controlled lateral gradient in morphology.
Upon combining photometry, ellipsometry and Xray
maps together with photoinduced absorption measurements,
we show how the gradual exposure to solvent vapor
results in a varying degree of polymer crystallinity for the
polythiophene/soluble fullerene system along one direction.
These morphologically graded samples are characterized by
a spectral photoresponse that depends on the specific location
in the area of the device where the light beam impinges,
a property that stands as proof-of-concept for position sensitive
detection. Moreover, we demonstrate that the development
of graded morphologies is an effective one-step method
which allows for fast performance optimization of organic solar
cells. Finally, the appropriateness of eight different solvents
for morphology control via vapor annealing is evaluated
in a time-effective way using the advanced method, which
helps to identify boiling point and solubility as the key processing
parameters.