Photoacoustic characteristics of carbon-based infrared absorbers

TL;DR

This study experimentally compares the photoacoustic responses of various carbon-based infrared absorbers across a broad wavelength range and low frequencies, highlighting soot as the most responsive material.

Contribution

It provides the first comprehensive comparison of photoacoustic responsivities of different carbon-based materials over a wide spectral and frequency range.

Findings

Candle soot coating shows the highest photoacoustic response.

Black paint and carbon nanotubes have lower responses.

Results inform selection of materials for photoacoustic detectors.

Abstract

We present an experimental comparison of photoacoustic responsivities of common highly absorbing carbon-based materials. The comparison was carried out with parameters relevant for photoacoustic power detectors and Fourier-transform infrared (FTIR) spectroscopy: we covered a broad wavelength range from the visible red to far infrared (633 nm to 25 um) and the regime of low acoustic frequencies (< 1 kHz). The investigated materials include a candle soot-based coating, a black paint coating and two different carbon nanotube coatings. Of these, the low-cost soot absorber produced clearly the highest photoacoustic response over the entire measurement range.