ABSTRACTUsing the sensitive absorption technique of Photothermal Deflection
Spectroscopy (PI1S) it is possible to detect subtle spectral features in the
absorption spectra of polymeric thin films that cannot be detected by other
means. This paper describes observations of weak charge-transfer complex
(CIC) formation and also light-induced changes in various organic films. The
filns studied were those commonly used as charge transport materials in
organic photoconductors, comprised of a small transport molecule and a
polymer binder. The optically measured CTC bands can be used to establish
single electron energy levels of the constituents. Reproducible
photo-induced changes are manifest both in the strong UV transitions as well
as in the “sub-gap” absorption and appear to be correlated with the
photo-chemical stability of the constituents. The light-fatigue has both a
reversible as well as irreversible component.
Charge Transfer into Organic Thin Films: A Deeper Insight through Machine‐Learning‐Assisted Structure Search
