ИСТИНА

We present high efficiency Ag-free low concentration indium-fluorine-oxide (IFO)/(n+pp+)Cz-Si/Al solar cells based on: (i) a shallow phosphorus-doped n+-emitter; (ii) an easy-to-fabricate screen-printed Al-alloyed Al-p+ back-surface-field (BSF); (iiii) transparent conductive IFO film grown by ultrasonic spray pyrolysis, which acts as passivating and antireflection electrode; (iv) Ag-free multi-wire metallization of copper wire attached by the low temperature lamination method simultaneously to the front IFO film, rear Al layer as well as to the interconnecting ribbons arranged outside the structure using transparent conductive polymer (TCP) films. The Al-p+ BSF was alloyed in a conveyor belt furnace. Peak firing temperature was varied in the range 820–940 °C. The highest results were obtained for the solar cells with Al-p+ BSF alloyed at 860 °C: in the operating range 1–12 suns, their efficiency varies from 18.3 to 19.2%.