We report on the theoretical investigation of a silicon-based interdigitated back contact back heterojunction (BHJ) solar cell that combines the advantages of heterojunction with intrinsic thin layer ...(HIT) solar cell and point contact back junction c-Si solar cell. Our results show an optimum bandgap for emitter (p-type a-Si:H) layer for this cell to be approximately 1.72eV. As we increase the bandgap from 1.3eV to 2.2eV, the open circuit voltage (Voc) increases from 0.45V to 0.75V and then saturates, while the short circuit current density (Jsc) remains constant at 35mA/cm2 up to about 2.0eV, and then decreases to zero. Fill factor (FF) increases from 57% to a maximum of 75% as the bandgap increases from 1.3eV to ∼1.72eV, respectively, and then decrease to 5% when the bandgap reaches 2.1eV. Efficiency increases from 7% and reaches a maximum of about 19% at around 1.7eV and then decreases to zero at 2.1eV. These results can be correlated to changes in valance band spike (barrier) when emitter bandgap increases from 1.3eV to 2.2eV, and are explained in terms of band alignment between p-a-Si:H/i-a-Si:H/n-type-c-Si.
► In the point contact structure undoped region at the rear side acts as reflector. ► Doped regions are shrunk to points and provide more space for undoped region. ► Point contact structure enhances reflection from the rear side. ► In the literature, no reason has been reported for choosing emitter bandgap of about 1.7eV. ► Improved band alignment enhances efficiency to a maximum when emitter band gap is around 1.7eV.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report the optimization of screen-printed phosphorus dopant paste diffusion on monocrystalline silicon wafers. The uniform sheet resistance and spatial selectivity offered by this diffusion ...approach make it promising for selective emitter, bifacial and interdigitated back contact solar cells. The sheet resistance, dopant profile and electrical characteristics of dopant paste diffused samples have been analyzed and the performance is benchmarked against conventional phosphorus oxychloride diffusion.
An IBC solar cell for the UPC CubeSat-1 mission Ortega, P.; Jove-Casulleras, R.; Pedret, A. ...
2013 Spanish Conference on Electron Devices,
01/2013
Conference Proceeding, Journal Article, Publication
Open access
In this work the fabrication and electrical characterization of interdigitated back contact IBC solar cells is shown. These solar cells have been specifically designed for a CubeSat based satellite ...under developement at the Universitat Politecnica de Catalunya (UPC). Solar cells incorporate a transparent cover-glass as an extraterrestrial radiation shield. Front surface passivation was achieved using an Al 2 O 3 layer exhibiting surface recombination velocities <; 100 cmls at the final device. Measurements confirm photovoltaic efficiencies η's-12%, with open circuit voltages Voc's ~650 m V and short circuit current densities J sc 's ~25 mA/cm 2 . A module with 11 IBC solar cells interconnected in series will be integrated in one of the faces of the satellite forming part of the power subsystem. Preliminary results confirm the good electrical performance of the module.
