A scalable and inexpensive surface-texturization method for advanced transparent front electrodes in microcrystalline and micromorph thin film silicon solar cells

As the thin film silicon solar cell technology reaches a pivotal point to keep competing in the photovoltaic industry where crystalline silicon and other technologies currently dominate, it has become an urgent task to revolutionize some of its state-of-the-art key processes which have reached their cost barriers for decades. We have devised a more cost-effective method for mass production of transparent front electrodes for thin film silicon solar modules. It involves sputtering deposition and a novel surface-texturization process. The new method produces microscopic U-shaped surface textures of aluminum-doped zinc oxide (AZO) and other transparent conductive oxides (TCOs) which lead to higher open circuit voltages, higher fill factors, and comparable short circuit current densities for microcrystalline and micromorph silicon solar cells. We experimentally demonstrate that solar cells using these TCO front electrodes reach comparable efficiency levels to those using any other commercialized TCO electrodes suchasfluorine-doped tin oxide (FTO) and boron-doped zinc oxide (BZO). An analysis shows that the manufacturing costs of the new method can be significantly lower than those of the commercial counterparts. The possibilities brought about by this method may pave a new path for future developments of thin film silicon solar cells. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim