A simple approach for fabrication of low-temperature processible inverted organic solar cells

Abstract

Small molecule electrolytes (SMEs) based on naphthalene diimide with various types of side chains, such as tosylate anion and zwitterion were synthesized for photovoltaic application as the cathode interlayer. These materials utilizedthe side chains to produce a beneficial interface dipole. With PM6:Y6BO as the active layer, the device based on NDIN-BS exhibited a PCE of 14.5%, which is almost the same as the PCE of the ZnO-based device (15.0%). The device based on NDIN-OTs exhibited a lower PCE of 14.2%, which mainly resulted from the significant decrease of the Jsc, but exhibit a higher FF due to the better contact with the active layer. This outcome showed that SMEs are suitable candidates to adjust the work function of ITO and provide an alternative to the ZnO interlayer, which relies on proper monitoring of the sol–gel transition by high annealing temperatures as high as 200 °C, leading to simplifying the manufacture of cost-effective OSCs.