Three different amorphous silicon structures of PV modules were analyzed in outdoor condition during one month. The Staebler-Wronski effect (or light induced degradation effect) is well known for the amorphous technology and depends strongly on the manufacturing process and its structure. Due to this effect, the amorphous PV modules loose performances compared to their initial characteristics. The behaviour, during and after the aging of different amorphous silicon PV module, is investigated and a new amorphous structure, less sensitive to the Staebler-Wronski effect and with a better response under real conditions of use is exposed.