  We control the anisotropic molecular packing of vapor-deposited glasses of
ABH113, a deuterated anthracene derivative with promise for future OLED
materials, by changing the deposition rate and substrate temperature at which
they are prepared. We find that, at substrate temperatures from 0.65Tg to
0.92Tg, deposition rate significantly modifies the orientational order in the
vapor-deposited glasses as characterized by X-ray scattering and birefringence.
Both measures of anisotropic order can be described by a single deposition
rate-substrate temperature superposition (RTS). This supports the applicability
of the surface equilibration mechanism and generalizes the RTS principle from
previous model systems with liquid crystalline order to non-mesogenic organic
semiconductors. We find that vapor-deposited glasses of ABH113 have
significantly enhanced density and thermal stability compared to their
counterparts prepared by liquid-cooling. For organic semiconductors, the
results of this study provide an efficient guide for using deposition rate to
prepare stable glasses with controlled molecular packing.
