Analysis of dual peak emission from Rhodamine 6G organic dyes using photoluminescence

Rhodamine 6G (R6G) or Rhodamine 590 is a cationic dye with a strong absorption in the visible and a high fluorescence yield. R6G is commonly used as a tracer dye in water to determine the rate and direction of flow and transport. Some examples of Rhodamine dye applications are fluorescence microscopy, flow cytometry, fluorescence correlation spectroscopy, etc. In this work, the optical properties of R6G with various concentrations in water were observed by mean of photoluminescence (PL) measurement. The experimental results showed that the higher the concentration, the greater the intensity of the photoluminescence. It is observed that R6G dye emission spectrum had two distinctive peaks, at 550 nm and 602 nm wavelengths. R6G dye concentration affected these peaks in a very interesting manner. With the increasing R6G concentration, the emission peak shifted from 550 nm, which is dominated by monomer, to 602 nm, which is dominated by dimer emission. Our findings have given a good clue in optimizing the concentration of R6G dye in order to give the best emission for various applications.