Commercial carbon nanotube as rear contacts for industrial p-type silicon solar cells with an efficiency exceeding 23%

Commercially available single wall carbon nanotube (SWCNT) soots are combined with an organic passivation scheme and shown to be an efficient rear contact and alternative to ALD-Al2O3/PECVD-SiNx/laser treatment in conventional passivated emitter and rear cell (PERC) solar cells. Both low carbonaceous purity 60–70% and 95% SWCNTs are tested and a power conversion efficiency of over 23% is demonstrated. The approach is simple, scalable and completely eliminates the metal-semiconductor contact known to cause high interfacial recombination in PERC technology. A low reverse saturation current density (J0) is achieved by varying the concentration and species of SWCNTs used and a full-area back surface field on an industrial sized (275.54 cm2) solar cell is obtained.