Aligned Nanofibers as an Interfacial Layer for Achieving High-Detectivity and Fast-Response Organic Photodetectors

We report that aligned nanofibers (ANs) prepared by electrostatic spinning technology as an interfacial layer can significantly enhance the performance of inverted organic photodetectors. With the insertion of ANs of titanium dioxide (TiO₂), the optimized organic photodetectors had a highest detectivity of 2.93 × 10¹³ Jones at zero bias, which is about 3 times higher than that of a similar organic photodetector without ANs and also markedly higher than that of traditional silicon photodetectors. The performance of the devices with different TiO₂ ANs as the interfacial layer was investigated, and the results exhibited that photodetectors with one-way ANs had the highest detectivity and shortest response time. This work provides a new application of nanofibers fabricated by a simple and controllable process in high-performance organic photodetectors

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

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