Chapter 17 - Intermediate Band Solar Cells (IBSC) Using Nanotechnology

Abstract

This chapter deals with the intermediate band solar cells using nanotechnology. The operation of the intermediate band solar cell (IBSC) relies on the electrical and optical properties of the intermediate band (IB) materials. These are characterized by the existence of an electronic band located between the conduction and valence bands of an otherwise conventional semiconductor band gap. The IBSC is a novel solar cell with a potential limiting efficiency that exceeds that of single gap solar cells. The higher limiting efficiency results from an increase in the photogenerated current while preserving its open-circuit voltage. This chapter describes the practical implementation of IBSCs through the use of InAs quantum dot technology, and have outlined the underlying theory on which the operation of IBSCs is founded. Moreover, characterization of QD–IBSCs has revealed the production of photogenerated current by below band gap energy photons. Analysis of a range of experimental results, reinforced with equivalent circuit modelling, has shown that the behavior of the QD–IBSCs is described in terms of distinct quasi-Fermi levels, one for each of the conduction band (CB), the valence band (VB), and the IB. Finally, two of the fundamental theoretical requirements for IBSCs have therefore, been demonstrated.