Inverted Spectra of Single-Wall Carbon Nanotube Films

Abstract

We present absolute measurements of reflectance and absorbance for a purified single wall carbon nanotube (SWCNT) film. The absorbance spectrum of a SWCNT-laminated pyroelectric detector for wavelengths 0.6−2 μm is inverted when compared to absorbance data in the literature, which is typically inferred by reciprocity from transmissivity measured by a spectrophotometer. This surprising behavior has been corroborated by diffuse reflectance measurements and suggests that reflectance dominates absorption for wavelengths near excitonic transitions.