In the dopant materials is change the power conversion efficiency in solar cell due to doping/defect? how? why?
Increasing the band gap with dopants increase the cell efficiency because the junction can absorb more energy from the spectrum.
Defects reduce solar cell efficiency by providing new recombination pathways (loss),
by allowing the light to generate heat rather than electricity. Defects induce deep
energy levels in the semiconductor bandgap, which degrade the carrier lifetime and
quantum efficiency of solar cells. One of the most reasons is the existence of
recombination centres, which trap photogenerated carriers before they reach the
solar cell terminals. Defects introduce energy levels in the bandgap, and act as
recombination centres, which reduce the free carrier lifetime.
Dear N.,
The doping has two effects on the level of the semicondcutor properties: The increase of the doping increases the mobile carrier concentration., It also decreases the mobility because the motion impedance of the defects produced by the doping atoms.
This has effects on the solar cells properties. It is so there is optimum doping concentration both in the substrate and emitter layers of the solar cells. As an example for silicon single crystal solar cells it is found that the optimum doping in the substrate is 10^17/cm^3 and in the emitter it amounts to 10^19/cm^3.
The effect of doping is of two fold:
If increases the open circuit voltage increases while the short circuit current decreases. Therefore the photoconversion efficiency at a specific doping.
By introducing microstructures in the solar cells we could enhance the properties of solar cells at heavy doping and thereby one can produce solar cells from less expensive materials as it is known that the prize of the material increases with its purity. I would like that you see our very new paper in the link: Article Performance Enhancement of a Proposed Solar Cell Microstruct...
I would like that you follow also the book chapter:https://www.researchgate.net/publication/323309527_Solar_cells_and_arrays_Principles_analysis_and_design
Best wishes
- some experimental studies have been reported in reference "C. Liu et al., « Improving the charge carrier transport of organic solar cells by incorporating a deep energy level molecule », Phys. Chem. Chem. Phys., vol. 19, no 1, p. 245‑250, 2017.DOI: 10.1039/C6CP07344A" consist the effect of p-type doping with F4-TCN concentration on organic solar cell based on P3HT:ICBA showed that there is an optimum doping ,it is about 6e16cm-3 .with this concentration a peak of effeciency and of short circuit currrent have been noticed, while the open circuit voltage remaind constant. So, I'am finding that there is a constraction whith Mr Abdelhalim Zekry when he said ",If increases the open circuit voltage increases while the short circuit current decreases. Therefore the photoconversion efficiency at a specific doping ". I don't know if this different depends to the marial used in constraction of solar cell.
Dear Meriem,
Welcome,
I spoke from metallic semiconductors such as silicon.
concerning the doping i said that there is an optimum doping. Your paper also has the same finding for the organic materials. The open circuit voltage increases with doping because the shift of the Fermi level toward the band edges when the doping increases and there by increasing the contact difference of potential in p-n homojunctions.
The behavior of the doping in organic materials is different from that of the metallic semiconductors. I attached references for these findings.
You can yourself see this behavior.
Best wishes
You can know more about doping and fabrication from Grabel book (Microelectronics) (Chapter five).
- Badges
- Science topic