Rhodamine 800 as reference substance for fluorescence quantum yield measurements in deep red emission range

The determination of fluorescence quantum yields (Φf) of deep red dyes emitting at 635–900 nm is difficult due to lack of suitable standards. In this work, we propose a commercial dye, rhodamine 800 (Rho800), as reference standard which belongs to the family of xanthenes. The quantum yield of rhodamine 800 in absolute ethanol has been studied using a relative method with cresyl violet (CV) and rhodamine 101 (Rho101) as references, and an absolute fluorometric method by integrating sphere measurements.