In‐situ series connection of an amorphous silicon photovoltaic tandem module

Abstract Local shading during thin film deposition monolithically interconnects thin film solar cells into photovoltaic modules. This in‐situ series connection method is, for the first time, applied to an amorphous silicon tandem cell structure. Sequential maskingand mask‐shifting forms the electrical series connection in‐situ, i.e. during the sputtering and plasma depositions of the contact and semiconductor layers of the thin film solar cell structure. The resulting photovoltaic module consists of five amorphous silicon tandem cells with a total module area A_{\rm m} =12.5\mathop {\;{\rm cm}}\nolimits^2. The module exhibits a fill factor {\rm FF}_{\rm m} > 72% and a total area efficiency \eta _{\rm m} =6.2%. Thermographic imaging proves successful patterning by local shading and attributes low shunt resistances of some component cells to single pinhole formation. The dark‐shunt resistance of each cell of the module amounts to R_{{\rm sc}{\rm,dark}{\rm,cell}} > 13\;{\rm k\Omega }\;{\rm cm}² and for the complete module to R_{{\rm sc}{\rm,dark}{\rm,module}} =454\;{\rm k\Omega }\;{\rm cm}². (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)