Single electron transfer in thermally annealed nanoparticle dropcast thick films

A very simple and effective procedure based on thermal annealing was reported in inducing discrete charge transfer in nanoparticle solid films. The particle ensembles were prepared by dropcasting a particle solution onto an interdigitated array electrode. The as-prepared particle films exhibited only linear featureless current-potential profiles in conductivity measurements, whereas after thermal annealing, well-defined staircase features of single electron transfer started to emerge at temperatures higher than 300 K. This was accounted for by the combined consequence of structural rearrangements of nanoparticle cores within the organic protecting matrix and thermal activation of interparticle charge transport.