REPRODUCIBLE PREPARATION OF SILVER SOLS WITH UNIFORM PARTICLE-SIZE FOR APPLICATION IN SURFACE-ENHANCED RAMAN-SPECTROSCOPY

This paper describes a new method for the preparation of silver colloi ds with a narrow range of particle size to be used in surface-enhanced Raman spectroscopy. Using malachite green as a strongly adsorbing dye , it can be shown that colloids from different preparation batches exh ibit the same enhancement factor within an error margin of about 15%. By varying the number of nucleation centers, the particle size can be determined at will. An increase in particle diameter from about 38 to about 76 nm leads to an estimated five-fold increase in surface enhanc ement.