Reduced Recombination by Fullerene Composited Metal Oxide as Electron Extraction Layers for Hybrid Optoelectronic Devices

Abstract

The performance of solar cells and photodetectors based on metal oxide/conjugated polymer hybrids was significantly enhanced by embedding fullerene (C₆₀) in the metal oxide of TiO₂. With the TiO₂–C₆₀ bulk composites as electron extraction layers, photodetectors based on poly­(3-hexylthiophene) (P3HT)/TiO₂–C₆₀ hybrids exhibited the highest detectivity of 6.54 × 10¹² jones at 520 nm and a fast response with the shortest rise time of 32 us. The key role of the C₆₀ in the TiO₂ layer is causing a fast electron transfer from defect state excitons to C₆₀, resulting in the suppression of the recombination of the defect state excitons produced by a fluorescence (Föster) resonance energy transfer process from photoinduced P3HT excitons to the TiO₂ defect states