Photophysical studies of novel lanthanide (Eu3+ and Tb3+) luminescent hydrogels

A group of lanthanide luminescent xerogels, CMa, CMb, CMc and CMd, exhibited specific emission responses towards to the temperature variation in polyelectrolyte hydrogels. The europium(III) containing materials decrease at a rate that follows the exponential function (y = 122.03e−0.0175x and y = 93.054e−0.0162x) whereas the terbium(III) systems undergo the linear decay process (y = −7.1733x + 677.64 and y = −6.5467x + 653.62). Interestingly, it has been shown that the excitation wavelengths for europium silica materials (CMa and CMb) embedded hydrogels can be extended into the visible region (415 and 465 nm respectively). In addition, the incorporation of lanthanide xerogels into polymeric hydrogel can obviously improve their thermal stabilities in water.