Freestanding SrNbO3 membranes as flexible transparent conductors

Synthesizing flexible transparent conducting materials is important for applications in flexible optoelectronics. Metallic oxide membranes offer great promise due to their large elasticity and high transparency. Among them, SrNbO3, a correlated metal, stands out as a promise transparent conducting oxide. However, synthesizing freestanding SrNbO3 membranes poses a challenge because it easily undergoes oxidation, resulting in degraded conductivity. To address this, we utilize epitaxial BaTiO3 capping layers, which effectively prevents SrNbO3 oxidation. We successfully fabricate millimeter-sized transparent conducting BaTiO3/SrNbO3/BaTiO3 membranes using water-soluble sacrificial layers. The obtained SrNbO3 (10 nm thick) membrane exhibits a room temperature sheet resistance (RS) of 174 Ω/sq and a transmittance (T) of 92% at a wavelength of 550 nm. The figure of merit (T10/RS) of this transparent conductor reaches 2.2 × 10−3 Ω−1 in the visible regime, comparable to SrNbO3 films on rigid substrates. These results open possibilities for applications as flexible transparent conductors.