Size Dependent Valence and Conduction Band-Edge Energies of Semiconductors Nanocrystals

Jacek and co-workers, from CSIRO, reported their research at the Journal of ACS Nano about the analysis of band energy for quantum dot materials with AC series^[1].
UPS, CV and PYSA are usually used to measure the band energy. However, UPS may damage the sample with the strong energy, and CV is lack of accuracy due to the selection of electrolyte and electrode. In contrast, PYSA can obtain an accurate result with simple operation.
Jacek and co-workers measured the valence band (E_vb) energy of CdSe, CdTe, PbS, PbSe of different particle sizes by AC-2. And conduction band (E_cb^opt) was calculated using the Evb and the photo absorption energy. From the result, the relationship between the particle size and band energy was uncovered.

The relationship between the particle size and band energy of CdSe.^[1]

E_vb: Valance band measured by AC-2 E_cb^opt: Conduction band calculated by Evb + photo absorption energy

[1] Jasieniak et al., ACS Nano, 2011, 5, 7, 5888-5902