Alloying Cs+ into Rb2ZrCl6:Te4+ toward highly efficient and stable perovskite variants

Doping or alloying in perovskites and perovskite variants provides a promising way for modulating the electronic and photoluminescence properties and the structural stability. In this work, a series of yellow-emitting Rb_2−xCs_xZrCl₆:Te⁴⁺ solid solution phosphors were prepared by a hydrothermal method, and their broad emission is assigned to the triplet ³P₁–¹S₀ self-trapped excitons (STEs). Upon increasing the alloying ion Cs⁺, the yellow emission can be greatly enhanced by a stronger Jahn–Teller distortion. Moreover, Cs₂ZrCl₆:Te⁴⁺ shows a high photoluminescence quantum yield (PLQY), and impressive thermal and anti-water stability. This doping–alloying strategy presents a new direction towards designing lead-free, high-performance and stable perovskite derivatives.