EuKNaTaO5: Crystal Growth, Structure and Photoluminescence Property
Abstract
The need for new optical materials for use in flat panel displays, optoelectronic devices, and biomedical imaging and sensing applications continues to advance the field of lanthanide doped luminescent materials, where the development of new materials that emit in the visible portion of the electromagnetic spectrum when excited by higher energy visible light is of particular interest.(1) Many of the trivalent lanthanides display luminescence due to the ease with which excited states can be populated, coupled with the prevalence of radiative rather than nonradiative decays to the ground state. Trivalent europium specifically has attracted attention due to its intense luminescence around 610 nm that can be generated by visible light excitation.(2) The local environment plays a crucial role in the intensity of this luminescence, and hence, many inorganic materials, including oxides,(3, 4) nitrides,(5) and other matrices,(2) have been evaluated as hosts for luminescent lanthanides. In such doped systems, typically, the luminescence reaches a maximum at a low doping level, around 2−3%, and subsequently decreases with increasing lanthanide doping concentration due to concentration quenching.(1-4, 6-8) For this reason, the observation of intense luminescence at 608 nm upon excitation at 535 nm in the novel bulk europium containing tantalate EuKNaTaO5 was unexpected. (Figure 1A).