Photoluminescence of noble metals

Abstract

We have developed an explicit model to explain the radiative recombination in noble metals, arising from transitions between electrons in the spconduction band and holes in the d-band generated by optical excitation. We find that the observed photon distribution has its shape from two competing factors. The first is due to the optics and the final density of states for the exiting photons. This is off-set by a d-band density of states factor increasing as the number of available d-states increase. We give a satisfactory account of the observed spectrum, using constant matrix elements, and find that luminescence can be used as a complementary tool to the ordinary elastic light scattering, giving detailed information about occupied and unoccupied states, provided the elastic optical constants are measured on the same sample.

Optical Properties and Ultrafast Dynamics of Metallic Nanocrystals

“…Photoluminescence from bulk copper and gold was first observed by Mooradian (68) and has been used extensively in characterizing the carrier relaxation and the band structure of metals (69)(70)(71)(72)(73)(74). It was found that the emission peak was centered near the interband absorption edge of the metal and therefore was attributed to direct radiative recombination of the excited electrons with holes in the d-band.…”

Ultrafast Optical Study of Small Gold Monolayer Protected Clusters: A Closer Look at Emission

“…21,22 For larger nanoparticles, the photogenerated d-hole is filled by the s-p electron near the Fermi level, which leads to very short-lived (hole lifetime ∼20-30 fs 61 ) visible emission. 62 The proximity of surface plasmon in terms of energy can enhance the fluorescence, thus leading the higher quantum yield as compared with bulk metal. 59 Surface states were used in reported literature 22,57,76 to explain the longer fluorescence lifetime in the NIR for nanoclusters.…”

Microspectroscopic characterisation of gold nanorods for cancer detection

“…As the longitudinal plasmon bands overlap with the tail of the sp→d emission, enhancement of this emission can occur, as was previously suggested. 178 The degree of overlap determines the degree of enhancement, as was experimentally established in Figure 5.6A. This phenomenon has been demonstrated before for the transverse plasmon bands.…”