The occurrence of energy transfer (ET) would enhance
the luminescence
of the activator but sacrifice that of the sensitizer. However, the
novel Sm3+-doped Ca2TbSn2Al3O12 (CTSAO) phosphor reported here seems to be an exception.
In the series of CTSAO:xSm3+ phosphors
investigated, something unexpected occurs; the activator, Sm3+, did not gain any energy compensation from the sensitizer, Tb3+, when temperature increases. Instead, when the loss of Sm3+ luminescence accelerates, simultaneously, the loss of Tb3+ luminescence accordingly alleviates. By careful calculations
on the ET efficiency of the CTSAO:0.06Sm3+ phosphor at
different temperatures, it is surprisingly found that the efficiency
keeps decreasing as temperature increases. It means that the Tb3+–Sm3+ energy transfer is capable of being
interrupted by an increasing temperature. By simulation, it is found
that the occurrence of thermal interruption of energy transfer benefits
the achievement of a higher temperature sensing sensitivity. In this
sense, making use of the thermal interruption of energy transfer could
become a novel route for further design of the fluorescence intensity
ratio-type luminescence thermometers.