Energy converting layers for thin-film flexible photovoltaic structures

The paper presents research focused on the efficiency improvement of inorganic flexible thin-film solar cells, using energy converting layers. The light capture enhancement was achieved through the introduction of layers based on rare-earth elements, as top coatings on the amorphous silicon photovoltaic structures. Such luminescent layers are converting high-energy photons into low-energy ones, which are more efficient in photovoltaic conversion of the investigated solar cells. Towards this goal, powders consisting rare-earth elements were applied as active particles in polymer layer. For practical experiments, the screen-printing method, as a cheap, reliable and industrially-ready technology was used for layers deposition. For the experiments two compositions were selected: Sr4Al14O25: Eu,Dy (BGL-300M) and SrAl2O4: Eu,Dy (G-300M). These materials are characterized by excellent thermal and optical stability and interesting luminescent properties (they absorb ultraviolet and emit in the visible range). For the verification of investigated materials and methods, various compositions of powders and proportions were tested and analyzed