Unfolding photophysical properties of poly(3-hexylthiophene)-MoS₂ organic–inorganic hybrid materials: an application to self-powered photodetectors

Self-powered photodetectors have grown as inevitable members of the optoelectronic device family. However, it is still challenging to achieve self-powered photodetection with good responsivity in the visible spectrum region. Herein, we report solution-processable poly(3-hexylthiophene) (P3HT)-molybdenum disulfide (MoS₂) organic–inorganic hybrid material, which can be used as the active layer in self-powered photodetectors. The morphological and structural properties of the synthesized P3HT-MoS₂ hybrid material has been discussed using atomic force microscopy and transmission electron microscopy, respectively. The hybrid material loaded with 1 wt% MoS₂ has shown an enhancement in the self-assembly of polymer in the form of fibrillar formation and excellent structural features in terms of π-conjugation. The self-powered photodetectors have been fabricated in indium tin oxide (ITO) coated glass/P3HT-MoS₂/Al configuration. The merit of P3HT-MoS₂ hybrid photodetectors is measured under the illumination of 470, 530, and 627 nm light in ambient conditions. P3HT-MoS₂ photodetectors show significantly higher responsivity and detectivity. The photo responsivity and detectivity in P3HT-MoS₂ devices are found to be 271.2 mA W⁻¹ and 4.4 × 10¹⁰ jones at zero bias, respectively, for 470 nm light with the optical power density of 74.1 μW cm⁻². Furthermore, the photocurrent switching behaviour at periodic illuminations of 1 Hz has also been examined for P3HT-MoS₂ self-powered photodetectors. (paper)