Author(s):
Abhigyan Ganguly^1a, Nandini Saha^2b, Saradindu Panda ^3c, Bansibadan Maji^4d, Madhuchhanda Choudhury^1e

Author Affiliation:
¹Department of Electronics and Communication, NIT, Silchar, India
²Department of Electronics and Communication, St. Mary’s Technical Campus, India
³Department of Electronics and Communication, Narula Institute of Technology, India
⁴Department of Electronics and Communication, NIT, Durgapur, India

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

In recent times a steady decrease in fossil fuel calls for urgent replacement of conventional energy sources. Thus solar cells that utilizes sun light as its source of energy often considered as one of the best options available. But solar cells have certain limitations. A photon of energy (=Eg eV) can excite only one electron from valance band to conduction band but if photon has energy (hv) greater than the band gap value (Eg) of the material, then excess energy will generate heat instead of generating extra electron-hole pairs (EHPs). Thus the overall efficiency is limited and it is known as Schockly and Queisser limit, which gives the maximum efficiency at 31%. Hence recently semiconductor quantum dots have been incorporated in them to overcome this low efficiency problem. In this paper, we give an introduction to Quantum Dot Solar Cells (QDSCs) and its working principles at the beginning. The quantum effects found in QDSCs like quantum confinement and MEG is also explained. The relation between absorption coefficient (α) and wavelength (λ) is established and α v/s λ curve is plotted for different materials (GaAs, InP, InSb, CdSe and ZnS). The wavelength at maximum absorption peak is used to determine the corresponding QD band gap. Finally, using the QD band gap value corresponding to maximum absorption, the QD sizes for the considered materials are determined using Hyperbolic Band Model.

KEYWORDS:
Solar cell; quantum dot; quantum dot solar cell; quantum confinement; electron-hole pairs (EHPs); hyperbolic band model