Sebastian Eisele

18.9% efficient full area laser doped silicon solar cell

A record in full area laser doped emitter solar cells with an efficiency η=18.9% is reported. Our patented, scanned laser doping process allows for the fabrication of defect free pn junctions via liquid state diffusion of predeposited dopant layers in ambient atmosphere without the need of clean room conditions. Our cells display an open circuit voltage Voc=677 mV, demonstrating laser doping to be comparable to furnace diffusion. Combining laser diffused pn junctions with a textured front side has the potential to boost the short circuit current density Jsc and thus the solar cell efficiency η to η>21%.

0.4% absolute efficiency gain of industrial solar cells by laser doped selective emitter

The formation of selective emitter with lower doped areas between the contact fingers and higher doped areas beneath the front side metallization increases the efficiency ¿ of crystalline silicon solar cells. The efficiency increases as a result of higher open circuit voltage and enhanced short circuit current density. The ipe laser doping process offers an elegant and reliable approach for the local formation of selective emitters. We use only one additional laser processing step after furnace diffusion. Thus, this patented process is easily integrated into an industrial production line without changing previous and subsequent processing steps. The phosphor silicate glass (PSG) layer, already grown on top of the emitter during furnace diffusion, serves as doping precursor. A laser locally melts the emitter surface and additional phosphorus atoms diffuse from the PSG layer into the emitter, increasing the doping concentration. This single additional processing step increases the efficiency ¿ of monocrystalline industrial solar cells by ¿¿ = 0.4% absolute.

Full area laser doped boron emitter silicon solar cells

We present full area laser doped boron emitter n-type silicon solar cells using sputtered boron as dopant source. Quasi-steady-state photo conductance decay measurements show a low emitter saturation current density J0e and an open circuit voltage limit of Voc,lim 702 mV for a 128 Ω/sq emitter proving the high quality of the laser doped boron emitters. The first 4 cm2 cell yield efficiencies up to η= 16.7% without optimization of the cell structure.

18.9% efficient silicon solar cell with laser doped emitter

A new record in laser doped solar cells with an efficiency ¿ = 18.9% is here reported. The ipe laser doping process allows for the fabrication of emitters of silicon solar cells via liquid state diffusion of predeposited dopant layers. Laser doping of sputtered phosphorus precursors results in an open circuit voltage Voc = 677 mV, thus, ipe laser doping is comparable to furnace diffusion.