posted on 2019-06-11, 00:00authored byInhwa Lee, Nicholas Rolston, Pierre-Louis Brunner, Reinhold H. Dauskardt
The effect of tuning
molecular weight (Mn) in poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]
(PTAA) to increase
both mechanical properties of the film and electrical properties of
perovskite solar cells is reported. Perovskite solar cell devices
are fabricated to investigate the effect of Mn on power conversion efficiency. Moisture stability for various Mn is also studied in PTAA films exposed to mechanical
loads in humid environments. Furthermore, cohesion and tensile tests
are employed to determine the mechanical properties of PTAA, where
higher Mn leads to more robust films.
To elucidate the effect of Mn on the debonding
kinetics, a viscoelastic fracture kinetic model is proposed as a function
of Mn, and the debonding mechanism is
found to be dependent on Mn. Finally,
the effect of small-molecule-based dopants on the mechanical stability
of PTAA is investigated.