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


•    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


•    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


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