Pronounced thickness effect of permanent charge-introduced branched poly(ethylene imine) surface-modifying layers in polymer:nonfullerene solar cells

The water-dipping effect of branched poly(ethylene imine) interfacial layers on the performance and stability of polymer:nonfullerene solar cells

“…The V OC change can be explained by the work function shift for the ITO electrodes, which could be caused by the formation of dipole layers due to the interaction between the ITO surface and the bPEI polymer. 33 As shown in Fig. 3a, the work function of ITO electrodes was effectively lowered from −4.8 eV to −3.99 eV by the presence of 0.5 nm-thick bPEI layers.…”