Temperature effects on the optical properties of thiol encapsulated gold nanoparticle thin films

The optical properties of 4-methylbenzenethiol encapsulated 3 nm gold nanoparticle thin films have been investigated for a range of temperatures and film thicknesses. The surface plasmon resonance absorbance peak shift is found to be sensitive to temperature, heating time and film thickness. Redispersion of the heat-treated material into chloroform became progressively more difficult with increasing temperature, suggesting changes to the chemical coating of the nanoparticles. Atomic force microscopy (AFM) data of the material after heating reveals structural changes corresponding to gold cluster growth following thiol desorption.