Solution processable graphene derivative used in a bilayer anode with conductive PEDOT:PSS on the non-fullerene PBDB-T:ITIC based organic solar cells

In this work, a semi-transparent, low-cost and easy processable graphene derivative and PH1000 (conductive PEDOT:PSS polymer) based bilayer anode, is presented as a sustainable potential alternative to ITO. The simple mechanical-synthesized graphene derivative was in aqueous-suspension processed (SPG) and drop-coated onto a common glass substrates. The SPG film presents a Raman intensity ratio (I-D/I-G) of 0.56 and a number of 7 sheets theoretically estimated. Modified PH1000 with dimethyl sulfoxide (DMSO) was spin-coated onto SPG layer. The bilayer anode (SPG/PH1000) exhibits a transmittance, roughness and resistance of 82% (550 nm), 9 nm and 22651/sq, respectively. The bilayer alternative electrode is used in the manufacture of organic solar cells (OSCs) based on the non-fullerene PBDB-T:ITIC active layer. Average power conversion efficiency (PCE) of 8.3% (best 8.6%) is attained for control devices (using ITO as anode) and 4.0% (best 4.2%) for devices with the alternative SPG/PH1000 bilayer anode. For OSCs fabrication, a vacuum free deposited top electrode Field's metal (FM, an eutectic alloy of Bi 32.5%, In 51% and Sn 16.5%, with a melting point above 62 degrees C) was used.

Automated summary

A novel bilayer anode material composed of a graphene derivative and PH1000 polymer is proposed as a sustainable alternative to ITO in the manufacture of organic solar cells. The new material exhibits good performance characteristics such as low cost and ease of processing, showing potential for replacing ITO as an anode material.