Ageing of organic photovoltaic devices in Benin environment (South-Sudanese climate)

This study compares the ageing processes of standard P3HT:PCBM bulk heterojunction solar cells upon exposure to a temperate (Belgium) and an equatorial (Benin) climate. Differences in degradation of non-encapsulated systems are attributed to humidity differences between the European and African environments. The decrease in the power efficiency is shown to be related to two processes: degradation of the optical absorption and charge transport in the active layer. The decrease of the absorption can be further accelerated upon light exposure. Rigid encapsulation tackles efficiently the degradation process under both climates. Devices fabricated in air yield almost similar performances that those fabricated in N2, confirming that the fabrication process can be carried out in simple environmental conditions. This supports the development of low-cost sustainable photovoltaic technologies in countries with limited economic resources but abundant solar radiation.