Acetylene Ion Enhanced Bonding of PbS Nanoparticles to Quaterthiophene in Thin Films

Lead sulfide (PbS) nanoparticles of ∼3–5 nm average diameter were codeposited into quaterthiophene (4T) organic films, which in some cases, were additionally modified by simultaneous 50 eV acetylene ion bombardment. The film composition and PbS–4T bonding were monitored by X-ray photoelectron spectroscopy (XPS) and laser desorption postionization mass spectrometry (LDPI-MS). S2p core-level XP spectra indicated that ion-modified films displayed enhanced bonding between 4T and PbS nanoparticles. LDPI mass spectra found thiophene fragments bound to PbS in ion-modified films. Computational simulations were used to investigate the mechanisms by which the incident particles chemically modified the thiophene–PbS nanoparticle interactions: molecular dynamics, density functional theory simulations were carried out on α-terthiophene (3T) analogues of 4T films interacting with (PbS)16 clusters. The simulations showed that, in the absence of acetylene ion modification, a weak charge transfer from the PbS cluster to t...