20% efficiency silicon solar cells

Further improvements in crystalline silicon solar cell performance have been obtained by combining the high levels of surface recombination control demonstrated in earlier passivated emitter solar cells with an improved optical approach. This approach involves the use of microgrooved surfaces which retain the advantages of pyramidally textured surfaces while avoiding some disadvantages of the latter. The approach results in a 5-6% improvement in cell short-circuit current density for cells fabricated on 0.1 and 0.2 Ω cm (p type) substrates. This results in an energy conversion efficiency for these devices above 20% under standard terrestrial test conditions (AM1.5, 100 mW/cm²) for the first time.