Copper phosphotungstate as low cost, solution-processed, stable inorganic anode interfacial material enables organic photovoltaics with over 18% efficiency

Abstract

The performance and lifespan of organic photovoltaics (OPVs) and organic light-emitting diodes (OLEDs) are highly dependent on the properties of anode interfacial layers (AILs). In this work, a low cost, methanol processed copper phosphotungstate (Cu003) as AIL is developed for OPVs and OLEDs. The Cu003 film features an optical bandgap of 3.9 eV, a work function of 5.08 eV, and a hole mobility of 9.78 × 10-4 cm2 V-1 s-1. Cu003 AIL exhibits superior stability, higher transmittance and carrier extraction capacity than PEDOT:PSS, and induces better optoelectronic field intensity distribution, contributing to exciton generation and recombination inhibition. Therefore, non-halogenated solvent processed OPVs incorporating Cu003 AIL and PM6:BTPBO-4Cl active layer afford a high efficiency of 17.6%, with an outstanding fill factor of 79.6%, exceeding those with PEDOT:PSS. Moreover, the device based on Cu003/PM6:BTP-eC9:PC71BM affords a remarkable efficiency of 18.2%. The flexible OPVs and OLEDs incorporating Cu003 AIL are also successfully demonstrated. Our research shows that the inorganic Cu003 AIL is stable, low-cost, ecologically friendly, and facile-processing for organic electronics.