Fabrication of Flexible and Semitransparent PTB7:PC71BM Organic Solar Cells

Abstract

Semitransparent bulk-heterojunction (BHJ) solar cells have attracted a strong attention due to the possible use in new photovoltaic applications. However, semitransparent BHJ solar cells on flexible substrates have not yet been developed. In this work, flexible BHJ solar cells were fabricated on an ITO/PET substrate using an inverted PET/ITO/PFN/PTB7:PC71BM/MoO3/Au device structure. The power conversion efficiency (PCE) of the device was 3.4 %. Fabrication of semitransparent solar cells was further demonstrated utilizing a MoO3/Au/MoO3 transparent anode. The semitransparent solar cell showed bifacial energy generation when illuminated from both front and backside. The PCEs with illumination from the ITO or Au/MoO3 side were 2.7 % and 2.1 %, respectively. These results showed that a semitransparent PTB7:PC71BM solar cell was successfully fabricated on flexible PET substrates.