Optical Property Regulation through Host–Guest Interaction in a Zero-Dimensional Zr Chloride

Halide perovskites, particularly zero-dimensional (0D) A2BX6-type structures, have garnered significant attention in diverse fields due to their exceptional photoelectric properties. This study focuses on the optical property regulation of 0D A2ZrCl6 through nonprotonated cation substitution (A = [(CH3)3SO]+ and [(CH3)4N]+) combined with different guest ions (i.e., Sb3+, Bi3+, and Mn2+). The varied host–guest interaction is regarded as the reason for the different luminescent behaviors. The Sb3+ dopant has a weaker interaction with the host [(CH3)3SO]2ZrCl6 than Mn2+ does. As a result, Sb3+@[(CH3)3SO]2ZrCl6 shows an excitation-dependent photoluminescence ranging from blue to orange, while Mn2+@[(CH3)3SO]2ZrCl6 exhibits only Mn2+ dopant emission under different excitation wavelengths. Besides the dopant effect on the host–guest interaction, the organic cation can impact the host–guest behavior as well. [(CH3)3SO]2ZrCl6 and [(CH3)4N]2ZrCl6 have different preferences for dopant ions. Sb3+ and Mn2+ are favorable in the host [(CH3)3SO]2ZrCl6, while Sb3+ and Bi3+ are adopted in [(CH3)4N]2ZrCl6. Due to the varied emission colors from Sb3+ and Bi3+ dopants, [(CH3)4N]2ZrCl6 possesses diverse photoluminescence behaviors through dopant engineering. Inside [(CH3)4N]2ZrCl6, Sb3+ and Bi3+ have a weak host–guest interaction, showing a varied PL from the host and guest emission centers under different excitations.