Elastomeric Indoor Organic Photovoltaics with Superb Photothermal Endurance

Abstract

AbstractDespite recent improvements in their power‐conversion efficiency (PCE), organic photovoltaics (OPVs) cannot yet be guaranteed stable in an indoor environment. In this study, the destabilizing effects of morphological evolution and molecular‐ordering variation on photoactive layers containing two to four photoactive components are investigated under realistic indoor photothermal (>55 °C for 1000 h) and mechanical (10% strain and 1000 cycles) deformation conditions. Layers with more stable morphologies are obtained by increasing the number of photoactive components; consequently, the quaternary OPVs show the best PCE retention (over 90% and 82% of the initial values after the photothermal and mechanical stresses, respectively). The increase in entropy caused by the additional components in the quaternary blend leads to a more balanced molecular arrangement and excellent photothermal stability. Stronger intermolecular bonding and less variation of molecular ordering likewise occur in the quaternary OPVs, enhancing their mechanical endurance.