Thermal Evaporation of Large-Area SnS2 Thin Films with a UV-to-NIR Photoelectric Response for Flexible Photodetector Applications

In addition to device flexibility, the retentivity performance of photoelectric materials after an extreme reverse-bending process is intrinsically important and desirable for next-generation advanced flexible optoelectronics. In this work, we designed and fabricated large-area flexible SnS2 thin films with a novel nanosheet/amorphous blended structure to achieve an outstanding flexible photoelectric performance via a facile evaporation and post-thermal annealing route. Crystal structure analysis showed that the obtained SnS2 thin films were constructed with nanosheets oriented parallel to the substrate which were surrounded and connected by the amorphous component with a smooth surface. This nanosheet/amorphous blended structure allowed extreme bending because of the adhesive and strain-accommodation effect that arises from the amorphous components. The assembled SnS2 flexible photodetectors can bear a small bending radius as low as 1 mm for over 3000 bending-flatting cycles without a drastic performance decay. In particular, over 90% of the initial photoelectric responsivity (40.8 mA/W) was maintained even after 1000 bending-flatting cycles. Moreover, the SnS2 thin film can convert photons to photocurrent over a wide spectral range from ultraviolet to near infrared. These unique characteristics indicate that the strategy used in this work is attractive for the development of future wearable photoelectric and artificial intelligence applications.