Extension of Ultraviolet Sensitivity and Enhancement of Electron Transfer Behaviour of Poly(3-hexylthiophene) (P3ht)-Titanium Dioxide Nanocomposites

Poly (3-hexylthiophene) (P3HT)-based conductive polymers exhibit superior optoelectronic properties and are utilized in sensors, organic light-emitting diodes, and organic photovoltaic applications. This research aims to synthesize a high-performance P3HT conductive polymer that incorporates titanium dioxide (TiO₂-30 nm) in various ratios of P3HT to TiO₂ nanoparticles, using solution processing enhanced by the spin coating method and improving its structural quality through thermal annealing. The study investigates how different P3HT: TiO₂ ratios affect the optoelectrical behaviours of the P3HT hybrid layer, including optical absorption, photoluminescence (PL), ultraviolet (UV) sensitivity, electron transfer rate, energy level, and electrical conductivity, and compares these results with previous findings. The results revealed that a 1:1 composition demonstrated the most balanced and enhanced performances. The integration of 30 nm TiO2 nanocomposites improved the electron transfer rate, photoluminescence (PL) quenching, electrical conductivity, and optical absorption. The 1:1 P3HT: TiO₂ showed substantial improvement in UV sensitivity resulting from the band alignment between P3HT and TiO₂. This optimized composition achieved an optical absorption intensity of 1.12 a.u. and a PL intensity of 610 a.u. It exhibited the highest UV sensitivity of 7.9 due to the optimal interfacial interaction. It demonstrated a maximum electron transfer rate of 1.0 a.u. with minimal recombination losses. The optical bandgap was observed as 2.30 eV and electrical conductivity as 1.8 × 10⁻⁴ S/cm. Thus, the current paper demonstrated an effective strategy to overcome the lack of UV detection of P3HT polymers, making them suitable for UV photodetector applications.