Platinum nanoparticles decorated multiwalled carbon nanotube composites as highly transparent, bifacial counter electrodes for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are low-cost solar energy conversion devices with variable color and transparency advantages. DSSCs' potential power efficiency output, even in diffuse light conditions with consistent performance, allows them to be used in building-integrated photovoltaics (BIPV) window applications. Significantly, the development of bifacial DSSCs is getting significant scientific consideration. Triiodide/iodide (I₃^–/I^–) redox couple-mediated DSSCs require highly effective and stable electrocatalysts for I₃⁻ reduction to overcome their performance constraints. However, the commonly employed platinum (Pt) cathodes have restrictions on high price and unfavorable durability. Here, we report platinum nanoparticles (Pt NPs) incorporated into multiwalled carbon nanotubes (MWCNT) composites with lower Pt content as an efficient bifacial counter electrode (CE) material for DSSC applications. Pt NPs were homogenously decorated over the MWCNT surfaces using a simple polyol method at relatively low temperatures. CEs fabricated using Pt/MWCNT composites exhibited excellent transparency and power conversion efficiencies (PCE) of 6.92% and 6.09% for front and rear illumination. The results are expected to bring significant advances in bifacial DSSCs for real-world window applications.