NREL
Spin-on Dopants Enabling Low-Cost Interdigitated Back Passivated Contact Solar Cells
Benjamin G. Lee, Derek M. Fogel, San Theingi, William Nemeth, David L. Young, Pauls Stradins National Renewable Energy Lab
MOTIVATION
• Patternable doping of passivated contacts for high efficiency solar cells
• Simpler and less costly than ion-implantation
• More versatile than in-situ doping
• Demonstrate high efficiencies with spin-on dopants
KEY RESULTS
• Excellent passivation:
• P dopant, iVoc = 727 mV
• B dopant, iVoc = 706 mV
• Ga dopant, iVoc = 731 mV
• Ga doping of passivated contacts not previously reported, and is a standout result for p-type material
Excellent Passivation with Spin-on Dopants
Dopant Profiles – SIMS
IBC Cell Process
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Application to Luminescent Solar
• Various tandem-on-silicon PV concepts have been proposed for >30% efficiency, which could use such a silicon solar cell
• One potentially cost-competitive option is a Luminescent Solar Concentrator (LSC) with Quantum Dots (QDs)
• Light above the QD bandgap is absorbed and re-emitted with >99% PL efficiency [manuscript in preparation]
• LSC guides the PL to small cells with matched bandgap, e.g. InGaP or GaAs
• Longer wavelength light passes through the LSC and is collected by Si bottom cell
