Laser processing of crystalline silicon solar cells

Laser annealing of liquid doping precursors forms the emitters of solar cells which reach remarkable efficiencies close to 15% on monocrystalline and 13% on polycrystalline 2×2 cm² silicon, without the need for vacuum equipment. Depositing the precursor liquids using spin on technology produces homogeneous dopant films, which yield homogeneously doped layers after laser annealing. Films deposited using spray or inkjet technology are more inhomogeneous and lead to fluctuations in the sheet resistance of the doped regions, indicating inhomogeneous emitter doping. Consequently solar cells from spin coated samples exhibit higher efficiencies than cells from spray coated samples.