2D Materials for Flexible Photo Detector Applications

Abstract

Flexible optoelectronics is an emerging technology due to their desirable features such as lightweight and high portability. A wide range of two-dimensional (2D) materials have received much attention and have been extensively studied due to their high carrier mobility, excellent mechanical flexibility and layer-dependent bandgap. These have strong intramolecular covalent bonds and weak intermolecular Van der Waals interactions making them promising active materials for flexible optoelectronic devices. Currently a wide range of 2D materials such as Graphene, semiconducting transition metal dichalcogenides (TMDCs), exfoliated Gallium sulfide (GaS) nanosheets, 2D perovskite platelets, Antimonene and Black Phosphorus (BP) are available to be used in the next-generation optoelectronic devices. Graphene is a widely studied 2D nanomaterial as it has extraordinary optical, electrical, magnetic and mechanical properties and graphene-based photodetectors are used in ultra-wideband range (300 nm ∼ 6 μm). TMDCs have bandgaps of 1–2 eV and among TMDCs, Tungsten disulfide (WS2) has a high optical absorption coefficient and large exciton binding energies of 700–800 meV making it a better alternative to Graphene. Exfoliated GaS nanosheets are promising materials for optoelectronics due to their strong absorption in the UV−visible wavelength region. 2D perovskite platelets-based optoelectronic devices exhibit excellent photo-responsivity and photoelectric characteristics. In recent years, Antimonene is used for flexible photodetectors as it showed a good responsivity and on/off ratio. BP has advantages such as high carrier mobility and tunable bandgap. This chapter is a review of 2D materials for flexible photodetector applications.