Quantum confinement induced shift in energy band edges and band gap of a spherical quantum dot

Abstract

We have proposed and validated an ansatz as effective potential for confining electron/hole within spherical quantum dot in order to understand quantum confinement and its consequences associated with energy states and band gap of Spherical Quantum Dot. Within effective mass approximation formalism, considering an ansatz incorporating a conjoined harmonic oscillator and coulomb interaction as the effective potential for confining an electron or a hole within a spherical quantum dot and by employing appropriate boundary conditions we have calculated the shifts in energy of minimum of conduction band(CBM) and maximum of valence band(VBM) with respect to size of spherical quantum dot. We have also determined the quantum confinement induced shift in band gap energy of spherical quantum dot. In order to verify our theoretical predictions as well as to validate our ansatz, we have performed phenomenological analysis in comparison with available experimental results for quantum dots made of CdSe and observe a very good agreement in this regard. Our experimentally consistent theoretical results also help in mapping the probability density of electron and hole inside spherical quantum dot. The consistency of our results with available experimental data signifies the capability as well as applicability of the ansatz for the effective confining potential to have reasonable information in the study of real nano-structured spherical systems.

Synthesis and characterisation of CdSe QDs by using a chemical solution route

“…The excited electron returns to the ground state and associating with the hole, then, the fluorescence of the QDs is generated. Due to quantum confinement effects, the energy of the emitted photon is determined by the crystalline dimension of the QDs [7]. By using various methods or employed Cd and Se precursors, many researchers have attempted to synthesise the CdSe QDs.…”

Direct Z-Scheme Heterostructures Based on MoSSe Quantum Dots for Visible Light-Driven Photocatalytic Tetracycline Degradation

“…Besides, a red shift trend occurred in MoSSe QDs as related to bulk components with the confined absorption peak of 450 nm. The cases suggested that the dimension declined introduced the quantum confinement effect in the band gap of photocatalysts, with altered photocatalyst absorption features. , No apparent pronounced change in the absorption edges of MoSSe was noticed when Se was presented, implying that the Se was combined through the surface of QDs relatively rather than doping. As well as, the absorption intensity of MoSSe QDs has pronounced, and the absorption in visible light range expands broader rather than adding to the Se, which is responsible for the broad-spectrum light absorption response of Se .…”

Enhanced Heterogeneous Photodegradation of Organic Pollutants by a Visible Light Harvesting CoO@meso–CN@MoS2 Nanocomposites

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