Metal halides RbCdCl3:Sb3+ and Rb4CdCl6:Sb3+ with yellow and cyan emissions obtained via a facile hydrothermal process

It is of great interest to obtain multiple luminescent products from a single reaction, such as existing core–shell nanomaterials and heterojunction nanomaterials, all with the aim of enriching the photoelectric properties of the materials. Here, we report a hydrothermal approach for creating crystals of needle-shaped RbCdCl3:Sb3+ and bulk-shaped Rb4CdCl6:Sb3+, two antimony doped-cadmium based metal halides. Two crystal materials with different shapes and phases can be synthesized simultaneously at the same stoichiometric ratio. RbCdCl3:Sb3+ is needle-shaped, whereas Rb4CdCl6:Sb3+ is bulk-shaped. Under 320 nm excitation wavelength irradiation, blue emission (490 nm) of Rb4CdCl6:Sb3+ and yellow emission (560 nm) of RbCdCl3:Sb3+ can be attained. Interestingly at low temperatures RbCdCl3:Sb3+ shows double peaked emissions (460 and 560 nm). This study investigates Sb3+-doped RbCdCl3 crystals that exhibit double luminescence as a result of intrinsic host self-trapped excitons and extrinsic dopant-induced self-trapped excitons (STEs), which are referred to as host STEs and Sb3+ dopant STEs, respectively. The construction of multicolor light-emitting devices is made possible by their color kinetics characteristics.