Abstract
Intermediate band solar cells (IBSCs) have an efficiency limit of 63.2%, which is significantly higher than the 40.7% limit for conventional single gap solar cells. In order to achieve the maximum efficiency, the total bandgap of the cell should be in the range of ~2 eV. However, that fact does not prevent other cells based on different semiconductor bandgaps from benefiting from the presence of an intermediate band (IB) within their bandgap. Since silicon (1.12 eV bandgap) is the dominant material in solar cell technology, it is of interest to determine the limit efficiency of a silicon IBSC, because even a modest gain in efficiency could trigger a large commercial interest if the IB is implemented at low cost. In this work we study the limit efficiency of silicon-based IBSCs considering operating conditions that include the use of non-ideal photon casting between the optical transitions, different light intensities and Auger recombination. The results lead to the conclusion that a silicon IBSC, operating under the conventional model in which the sub-bandgaps add to the total silicon gap, provides an efficiency gain if operated in the medium-high concentration range. The performance of these devices is affected by Auger recombination only under extremely high concentrations.
Highlights
The idea behind the intermediate band solar cell (IBSC) [1,2] concept is the absorption of sub-bandgap energy photons to produce electric work
The efficiency limit of silicon-based IBSCs is calculated with the model and considerations described above
Enhancement of the photocurrent norenable to theanradiative recombination, so the operation of Results from Figure 3 corroborate what we advanced previously regarding that the efficiency an IBSC is equivalent to the one of a single gap cell
Summary
The idea behind the intermediate band solar cell (IBSC) [1,2] concept is the absorption of sub-bandgap energy photons to produce electric work These photons are absorbed by engineering a semiconductor-like material that, in addition to the conduction and valence bands, exhibits an intermediate band (IB) within the otherwise conventional semiconductor gap. The absorption of sub-bandgap photons is illustrated in Figure 1 by the arrows labeled a1 and a2 This absorption produces an increase in cell photocurrent, providing a gain in efficiency if the output voltage is not limited by any of the sub-bandgaps EL nor EH. The IB is isolated from the metal contacts by means of conventional semiconductors (called emitters) in order to assure that the output voltage is limited by EG
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
