Semi-transparent micro-stripped thin-film photovoltaics for energy-harvesting windows

Building-integrated photovoltaics (BIPV) promises a solution for on-site renewable electricity enabling zero-energy buildings. Semi-transparent photovoltaics (STPV) is an emerging technology to enable power-generating windows, complementing existing BIPVs. PV windows combine three functionalities: (i) as building blocks they transmit sunlight into the building; (ii) as power generators they convert solar energy into electricity; and (iii) as thermal regulators they block infrared radiation, reducing undesired heating. However, currently available STPV technologies provide low performance or unpleasant colored or disturbed viewing experience. In TRANSMIT, we will perform spatial segmentation of solar cells in the form of micro-stripes indistinguishable by the human eye, separated by clear glass thus allowing light transmission. We will use two PV technologies with efficiencies superior to 20% in their opaque form: (i) thin-film Cu(In,Ga)Se2 (CIGS) solar cells and (ii) halide perovskites with prospects of being the next-generation PV technology. In (i) we will microstructure CIGS on glass using photolithography, sputtering, and lift-off techniques; in (ii) we will print the perovskite material and use laser ablation to make clear micro-lines thus creating transparency. Device performance assessment, characterization ,and outdoor testing will be performed as well as life-cycle analysis, life-cycle cost, and screening future potential from sustainability and economic aspects.