Temperature dependences of optical energy gaps of SbSI@CNT and SbSeI@CNT

This paper presents for the first time temperature dependences of optical energy gaps of SbSI@CNT and SbSeI@CNT, i.e. carbon nanotubes (CNTs) filled with antimony sulfoiodide (SbSI) and antimony selenoiodide (SbSeI). The heterostructures were prepared sonochemically using CNTs and elemental Sb, S or Se and I in the presence of solvent under ultrasonic irradiation. Spectral characteristics of diffusive transmittance and reffectance of SbSI@CNT and SbSeI@CNT were measured in temperature range 274 K < T < 333 K. The determinal temperature dependence of indirect forbidden optical energy gap of SbSI@CNT has been fitted with E_gIf (T) = (1.92(2)-3.6(6) ×10^-4T) eV. Indirect allowed optical energy gap of SbSeI@CNT has been fitted with E_gIa(T) = (1.817(5) - 7.1(2) × 10 ^-4 × T) eV.