Absolute quantum yield measurements of near-infrared emission with correction for solvent absorption.

In this work, we evaluated the effect of solvent absorption during photoluminescence quantum yield (PLQY) measurements of near-infrared (NIR) emission with an integrating sphere (IS) instrument, and propose an effective correction method. Transmittance spectra of representative solvents measured with an IS instrument showed significant absorption bands in the first NIR region (NIR-I; 700-950 nm), and more prominently in the second NIR (NIR-II; 1000-1700 nm) region due to overtones and a combination of fundamental vibrations involving C-H and O-H stretching modes. The emission spectra of typical NIR-I and NIR-II emitting compounds exhibited dips owing to solvent absorption, resulting in somewhat reduced PLQY values. We utilized the transmittance spectrum of the solvent to correct the observed emission spectrum. Distortion due to solvent absorption was properly corrected, and additional corrections for the reabsorption/reemission effect gave more reliable PLQY values.