Multi-interfacial polyaniline-graphene/platinum counter electrodes for dye-sensitized solar cells

• Polyaniline-graphene complexes are synthesized by a reflux strategy.
• Multi-interfacial (PANi-G/Pt)n electrode is assembled by a LbL technique for DSSC.
• The DSSC with (PANi-10wt‰G/Pt)9 electrode yields an efficiency of 7.45%.
• The concept is applicable to other multi-interfacial CE systems.

Pursuit of multi-interfacial counter electrodes (CEs) for enhanced triiodide (I3−) reduction reaction has been a persistent objective for dye-sensitized solar cells (DSSCs). Here we report the synthesis of multilayer CEs consisting of positively charged polyaniline-graphene (PANi-G) complex and negatively charged platinum (Pt) nanoparticles. The (PANi-G/Pt)n (n represents the bilayer number) multilayer displays multi-interfaces for I3− reduction and charge transfer. Moreover, the complexation between PANi and G can markedly accelerate the electron migration from G to PANi. The DSSC with (PANi-10wt‰G/Pt)9 electrode yields an impressive power conversion efficiency of 7.45% under simulated air mass 1.5 global sunlight. The promising efficiency along with cost-effectiveness and scalable materials demonstrates the multi-interfacial CEs to be good candidates for robust DSSCs.