Spectroscopic ellipsometry thin film and first-principles calculations of electronic and linear optical properties of [(C9H19NH3)2PbI2Br2] 2D perovskite

The linear optical properties: the real ε1(ω) and imaginary ε2(ω) parts of dielectric function, the refractive index n(ω) and the extinction coefficient k(ω), are calculated and compared with experimental spectroscopic ellipsometry spectra.279