Formation of quasi-one-dimensional carbon chains in cubic nanocrystals by photon-breaking of C-S bonds in polythiophene

A solid polythiophene pellet was ablated by a KrF excimer laser beam to dep osit thin films on silicon substrates. The laser-ablated plasma was studied by optical emission spectroscopy to identify the photon-breaking of C-S bo nds in the ablated heterocycles. Raman and x-ray photoelectron spectroscopy measurements of the deposited thin films also supported the selective phot on-induced bond breaking. After eliminating sulfur in the molecular structu res, the thin films appeared to be composed of cubic nanocrystals with a un iform size of 240 nm. X-ray diffraction measurement determined the cubic cr ystal structures with a lattice constant of alpha = 3.38 Angstrom and sugge sted a quasi-one-dimensional carbon chain structure along the body diagonal of the cube.