Optical Properties of Zincblende Cadmium Selenide Quantum Dots

Abstract

Although wurtzite cadmium selenide quantum dots (wz-CdSe QDs) are one of the best explored colloidal nanomaterials, no detailed investigation of the optical properties of zincblende cadmium selenide quantum dots (zb-CdSe QDs) has been performed until now. Typically, it is assumed that this material shows the same behavior as the wurtzite modification. To investigate this, we present a study on the optical properties of zb-CdSe QDs, yielding the electronic band gap to size relation (sizing curve), the extinction coefficient at short wavelengths, and the oscillator strength of the band gap transition. Comparing these results with literature data on wz-CdSe QDs we observe, despite a deviation of the sizing curve for diameters above 4 nm, a similar extinction coefficient at short wavelengths and a similar oscillator strength.

Tuning Intraband and Interband Transition Rates via Excitonic Correlation in Low-Dimensional Semiconductors

“…The inset of Figure 2 (a) shows that, indeed, the intrinsic absorption at 4 eV remains nearly constant for a series of different laterals sizes (areas) of the nanoplatelets at fixed thickness of 4.5 ML. Similar findings have been obtained for semiconductor quantum dots and nanorods, [33][34][35] and they enable accurate concentration determination using effective media and local field theory. However, to our knowledge, the reason for this universal volume scaling has remained unclear.…”

The absorption coefficient of PbSe/CdSe core/shell colloidal quantum dots

“…For PbSe, 4 PbS, 5 wurtzite and zinc blende CdSe, [6][7][8] InAs, 9 and ZnO 10 QDs, it was shown that at high energies ͑3.1 eV for PbSe and PbS, 3.54 eV for CdSe, 2.76 eV for InAs, and 5.0 eV for ZnO͒, i is independent of the QD size. Moreover, it generally coincides with the theoretical value calculated using bulk optical constants and the Maxwell-Garnett effective medium theory as follows: 11,12…”

Luminomagnetic Silica-Coated Heterodimers of Core/Shell FePt/Fe3O4 and CdSe Quantum Dots as Potential Biomedical Sensor

“…The first three excitons can be seen on the UV-Vis spectra of CdSe quantum dots showing the formation of homogenous particles [43,45]. The first excitonic band located at 516.7 nm, 1S( ) − 1S 3/2 (ℎ) transition, indicated that the mean quantum dots diameter is ∼2.64 nm using Jasieniak and coworkers equation [46], and a band gap energy value about 2.42 eV was obtained using Kareľ Capek and coworkers equation for zinc blend CdSe [47]. The emission spectra show an intense photoluminescence around 534 nm (2.32 eV) with quantum yield up to 5% compared to Rhodamine 6G [46,48].…”