Boosting the Transparency of Metallic SrNbO₃ Through Ti Doping

In recent years, various materials have been developed to reduce the reliance of industries on indium, a primary component of transparent conducting oxides (TCOs), currently used for several optoelectronic devices. The search for indium-free TCOs calls for new materials, and perovskite oxides such as strontium vanadates, niobates, and molybdates offer good prospects. These perovskites are strongly correlated metals exhibiting high intrinsic electrical conductivity but, at the same time, have a good transparency. In this work, focus is placed on strontium niobate (SrNbO₃) thin films and manipulate their optical conductivity by Ti substitution which shifts the plasma frequency and reduces electronic correlations. This allows achieving a low resistance of SrNb_1−xTi_xO₃ (x = 0–0.5) thin films while maintaining a high transparency in the visible light spectrum. An optimal figure-of-merit (FOM) of 10.3 (10⁻³ Ω⁻¹) is obtained for x = 0.3. This FOM is comparable and possibly outperforms the optoelectronic capabilities of epitaxial Tin-doped Indium oxide (ITO) and several other proposed transparent conductor materials. The research paves a way for designing the next generation of transparent conductors, guided by insights from density-functional theory (DFT) and dynamical mean-field theory (DMFT).