Quenching-free fluorescence enhancement on nonmetallic particle layers: Rhodamine B on GaP particle layers

Thin rhodamin B dye layers were deposited on gas-evaporated GaP particle layers and their fluorescence intensities were compared with those of the dye layers simultaneously deposited onto glass substrates. The intensities of the dye layers on the GaP particle layers were found to be greatly enhanced and the enhancement factor increased from ∼10 to ∼140 as the thickness of the dye layer is decreased from ∼50 to ∼1 nm. The present results clearly demonstrate that GaP particle layers, although they are not metallic and do not support surface plasmons, are good enhancer of fluorescence free from quenching.