Quantum Dots-Based Solar Cells for Potential Application

Abstract

Most of relevant literature uses three-dimensional systems, while an effective reduction of geometry to two or one-dimension occurs in case of atoms and electrons localized on crystal imperfections. The motion of electrons in a layer is two-dimensional, and the excitations in the perpendicular direction are strongly quantized. Due to strong confinement imposed in all three spatial dimensions, quantum-dot systems are similar to atoms and therefore are frequently referred to as the artificial atoms, super-atoms, or quantum-dot atoms. Current experiments concerned with quantum dots (QDs) focus mainly on studying their optical and electric properties. Since QDs absorb and emit light in a very narrow spectral range, which is controlled, for instance, by an applied magnetic field, it seems that they might very soon find application in the construction of more efficient and more precisely controllable semiconductor lasers. The researchers are fascinated from the rich physics of semiconductor QDs and their high potential application. Most advances of QDs present specific important applications for inserting nanotechnology into renewable energy field. Nanotechnologies are attracting increasing investments from both governmental and non-governmental sectors that offer great opportunities to predict specific properties for technological potential application. The density functional theory via full potential-linearized augmented plane wave method is implemented in WIEN2K code to calculate the indirect energy gap (Γ-X). Modern implementations allow for a number of approximations to exchange and correlation and make no approximations to the shape of the crystal potential, unlike methods employing the atomic sphere approximation which assume spherical symmetry around each atom. The Engel–Vosko generalized gradient approximation and modified Becke Johnson formalisms are used to optimize the corresponding potential for energetic transition and optical property calculations of specific semiconductors as a function of QD diameter and are used to test the validity of our model of QD potential. The refractive index and optical dielectric constant are investigated to explore best potential applications for solar cells. The calculated results agree with other experimental and theoretical data.