On the Absorption Cross Section of CdSe Nanocrystal Quantum Dots

The linear absorption cross section is a crucial parameter to the design of nanocrystal quantum dot devices and to the interpretation of spectroscopic data. We measure and report the size-dependent absorption cross section of CdSe nanocrystal quantum dots. We compare the results for absorption far above the band edge, where the quantum dot density of states may be approximated as a continuum, to simple theoretical models of light scattering from light-absorbing small particles. Excellent agreement with theory is found for dilute dispersions in hexane. We find that for absorption at 350 nm the per particle absorption cross section Cabs (in cm2) for CdSe is Cabs = (5.501 × 105)a3 cm-1, where a is the particle…