Bending Photoluminescence and Surface Photovoltaic Effect on Multilayer InSe 2D Microplate Crystals

Recently bendable and flexible optoelectronics have attracted more attentions on display technology and concaved or curvy photovoltaic devices owing to the flexibility and softy in layered materials. The bending photoluminescence (BPL) and surface photovoltaic effect of a thin multilayer InSe 2D crystal are demonstrated here by using PL and surface photovoltage (SPV) experiments. The BPL result of InSe (t ≈ 30 nm) shows an enhancement in light intensity with respect to that of the other flat PL measurement owing to the spreading of emission solid angle for the irradiant Se‐In‐In‐Se basic units under concaved upward condition. The band edge structure of multilayer InSe is analyzed. The SPV measurement of an In mesh‐coated InSe microplate demonstrates that the Schottky‐type solar cell converts sunlight starting from ≈1 eV with the auxiliary of surface states on InSe. An initially formed In‐InSe Schottky solar cell (surface area of ≈2 mm² and thickness of ≈85 μm) is also tested. The testing result shows a photovoltage of V ≈ 24 mV can be generated from the Schottky solar cell under the illumination of Hg lamp with power density of P ≈ 0.83 mW cm⁻². All the experimental results demonstrate flexible light‐emission capability and “1 eV” photoelectric conversion capacity existed in the 2D multilayer ε‐InSe.