Enhancing 3G ETA solar cells with novel Bi2Se3 nanoparticles synthesized on TiO2: Impact of immersion cycles on PEC performance

The development of unexposed layer heterostructures by integrating metal chalcogenide semiconductors with metal oxide arrays offers a promising approach to enhance surface area, expand optical response, and improve charge kinetics key factors for achieving high-performance photoconversion devices. In this study, we introduce a facile, room-temperature chemical method using successive ionic layer adsorption and reaction (SILAR) to deposit Bi 2 Se 3 nanoparticles onto spin-coated TiO 2 arrays. We systematically explore the structural, optical, and surface morphological properties of the resulting TiO 2 /Bi 2 Se 3 heterostructures. Our findings reveal that the thin layer of Bi 2 Se 3 nanoparticles uniformly coats the porous TiO 2 , extending its optical response into the visible region. We also examine the charge kinetics and solar cell performance of devices constructed with an fluorine doped tin oxide (FTO)/TiO 2 /Bi 2 Se 3 /polysulfide/carbon-coated FTO sandwich-type architecture. Through comparative analysis, we assess the initial characterizations, charge kinetics, and photovoltaic performance of the TiO 2 /Bi 2 Se 3 heterostructures across different SILAR cycles. Our results demonstrate a significant enhancement in photocurrent for the bilayer TiO 2 /Bi 2 Se 3 architecture (0.55 mA/cm²) compared to bare TiO 2 (0.041 mA/cm²). This research highlights the potential of the proposed heterostructure to improve the efficiency of energy conversion devices. • Facile chemical routes for TiO2/Bi 2 Se 3 heterostructure fabrication at room temperature. • Structural, optical, and morphological analysis of heterostructures with Bi 2 Se 3 . • Enhanced visible optical absorption by tuning Bi 2 Se 3 size through immersion cycles. • Bi 2 Se 3 nanoparticles as light sensitizers boost light conversion in TiO 2 . • Photoconversion efficiency of 0.063%, electron lifetime 241 µs, resistance 12.66 Ω with 9 cycles.