LAUSR

CuInSe2 nanocrystals offer promise for optoelectronics including thin-film photovoltaics and printed electronics. Additive manufacturing methods such as photonic curing controllably sinter particles into quasi-continuous films and offer improved device performance. To gain understanding of nanocrystal response under such processing conditions, we investigate impacts of photoexcitation on colloidal NC lattices via time-resolved X-ray diffraction. We probe three sizes of particles and two capping ligands (oleylamine and inorganic S2-) to evaluate resultant crystal lattice temperature, phase stability, and thermal dissipation. Elevated fluences produce heating and loss of crystallinity, the onset of which exhibits particle size dependence. We find size-dependent recrystallization and cooling lifetimes ranging from 90 - 200 ps with additional slower cooling on the nanosecond timescale. Sulfide-capped NCs show faster recrystallization and cooling compared to oleylamine-capped NCs. Using these lifetimes, we find interfacial thermal conductivities from 3 to 28 MW/m2K demonstrating that ligand identity strongly influences thermal dissipation.