(color online) (a) Typical I–V characteristics of the device under different strains. (b) Calculated barrier height change of PEDOT:PSS/ZnO heterojunction as a function of strain. (c) Time-resolved characteristic of UV response with different strains. (d) Schematic of energy band structure of PEDOT:PSS/ZnO heterojunction with and without the presence of strain, shown in red and black curves, respectively.