banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Overcoming the bandgap limitation on solar cell materials
Rent this article for
View: Figures


Image of FIG. 1.
FIG. 1.

(Color online) A spectrally selective reflector prevents photons with energies between the bandgap (Eg ) and the reflector edge (Δ) to be absorbed (red lower left arrows), while allowing higher energy photons to be transmitted (blue upper left arrow). This reflector confines band-to-band recombination photons (dashed red line) from escaping, resulting in an accumulation of electrons (black dots) such that the Fermi level (dotted line) is shifted. At equilibrium, photons escape the cell (dashed green arrow, upper right) with energies above the bandgap, shifted by the reflector bandwidth.

Image of FIG. 2.
FIG. 2.

(Color online) (a) Total thermodynamic efficiency calculation for varying bandgaps (Eg ) and reflector bandwidths (Δ). The ≈30% efficiency peak shifts to the left for larger values of bandwidth. (b) A reflector bandwidth of 0.5 eV will shift the regular detailed balance curve (black curve, right) to the left (blue curve, left), allowing non-optimal semiconductors to achieve maximal thermodynamic efficiency. Overlaid are the bandgaps of some semiconductors traditionally used in solar cells (Si, GaAs and CdTe; red), as well as some potentially new solar cell materials (GaSb and FeS2; green).

Image of FIG. 3.
FIG. 3.

(Color online) Efficiency increase per thickness (L) and reflector bandwidth (Δ) including Auger losses for: (a) GaSb, a direct bandgap material with Eg  = 0.73 eV, ni  = 1.5 × 1012 cm−3 and CAug  = 5 × 10−30 cm6/s; (b) FeS2 (Pyrite), Eg  = 0.9 eV, ni  = 2.78 × 1012 cm−3 and CAug  ≈ 10−29 cm6/s. (Assuming Auger recombination as the dominant loss mechanism.) (c) The absolute efficiency change of GaSb, including the absorption coefficient dependence on the thickness (L), in addition to the Auger losses.


Article metrics loading...


Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Overcoming the bandgap limitation on solar cell materials