Surface sensitive Aurivillius materials are investigated in the present work for tailorable IR-activity, carbon contamination and supplemented UV-Vis absorption besides having broad PTC signature. Introduction of tantalum onto niobium sites strengthens octahedron rigidity and checks oxygen leaving unit cell positions to occupy surface interstitials. High solid solubility between tantalum and niobium oxide compounds permits systematically increasing unit cell volume. Optical and electrical energy bandgaps are investigated on doping tantalum besides tailoring IR-activity of unit cell. Equal doped sample with x=1.0 offers broadened PTC region by nearly 400% compared to other samples. Energy states are estimated to overlap in diffused manner on doping tantalum to increase amount of UV-Vis spectrum absorption in x=1.0 material. Differential thermal analysis (DTA) was used to confirm diffused phase transition behavior with release in lattice strain on doping tantalum in SrBi1.98La0.02Nb1-xTaxO9 (SBLNT) materials. © 2021 Author(s).