Interface engineered Ba1-xZnxSnO3/TiO2nanorod heterostructured photoanodes for efficient dye-sensitized solar cells

Abstract

Dye-sensitized solar cells (DSSCs) face persistent challenges, including low power conversion efficiencies (PCE), inefficient charge carrier transport, and substantial electron recombination losses. To address these issues, we present a previously unexplored ABO<inf>3</inf>/MO<inf>x</inf> heterostructured photoanode comprising Zn-doped BaSnO<inf>3</inf> (Ba<inf>1-x</inf>Zn<inf>x</inf>SnO<inf>3</inf>) microrods integrated with one-dimensional TiO<inf>2</inf> nanorods (TNRs) and coupled with a low-cost carbon counter electrode. This is the first report demonstrating the synergistic effect of Ba<inf>1-x</inf>Zn<inf>x</inf>SnO<inf>3</inf>/TiO<inf>2</inf> heterointerfaces on DSSC performance. The optimized Ba<inf>0.975</inf>Zn<inf>0.025</inf>SnO<inf>3</inf>/TiO<inf>2</inf> (ZB25T) photoanode achieves a 102 % increase in PCE (3.66 % vs. 1.81 % for pristine TNRs), driven by an enhanced short-circuit current density (16.44 mA cm−2) and improved open-circuit voltage (496 mV). In support, Electrochemical impedance spectroscopy (EIS) and charge transport analysis revealed that the optimized ZB25T photoanode exhibited the lowest charge transfer resistance (R<inf>Ct</inf> = 0.98 Ω), highest recombination resistance (R<inf>Cr</inf> = 48.3 Ω), longest electron lifetime (τ<inf>e</inf> = 1.21 s), extended diffusion length (L<inf>e</inf> ∼ 6.4 μm), and highest conductivity (σ = 9.4 × 10−5 Ω−1 cm−1). These synergistic improvements effectively suppressed recombination and enhanced charge transport, thereby justifying the superior short-circuit current density (J<inf>SC</inf>) and open circuit voltage (V<inf>OC</inf>) observed in DSSCs. Thus, this heterostructure offers a promising route toward efficient and stable DSSCs while reducing material-related costs through the use of a carbon counter electrode and solution-based synthesis steps. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.