Date of Completion
Honors College Thesis
Organic thin film semiconductors, excitons, phthalocyanines
For this thesis the effects of strain on excitons in organic thin film semiconductors is investigated.
A hollow-capillary pen writing technique was used to create highly ordered thin films deposited
on a flexible substrate. Metal-free octabutoxy-phthalocyanine (H2OBPc) was chosen for this
study because it forms long chains of molecules with strong π −π interactions. Absorbance and
linear dichroism measurements were performed on films with varying levels of strain applied along
the stacking axis, with the total strain averaging 8%. A k-vector study was also conducted to
investigate whether the molecular stacking angle is changing due to strain. It was hypothesized
that strain applied along the stacking axis would cause a peak shift in the absorbance spectrum,
and could potentially cause a shift in the molecular stacking angle of each molecule relative to
the substrate. Red-shifting of the exciton peaks was observed in both the absorbance and linear
dichroism spectra. An overall reduction in the linear dichroism was observed regardless of the
incident angle in the k-vector study, indicating that the molecular stacking angle is changing.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.
Czar, Katrina E., "Strain Effects on Coherent Excitons in Organic Crystalline Thin Films" (2019). UVM Honors College Senior Theses. 444.