Scanning the optical characteristics of lead-free cesium titanium bromide double perovskite nanocrystals

Cs_(2)TiBr_(6) nanocrystals(NCs)are a type of promising optoelectronic materials,owing to their high photoelectric properties and non-toxicity.Here,we synthesize the colloidal Cs_(2)TiBr_(6)NCs using a hot-injection approach.The temperaturedependent absorption data shows that its energy band changes about 30 me V with temperature,reflecting that its energy band structure is much stable.The excitation intensity-dependent transient absorption data confirms its linear absorption cross-sections and carrier recombination rate constants,involving monomolecular and bimolecular recombination,which are all superior to those of conventional perovskite bromide counterparts.In addition,its nonlinear absorption cross-sections are also measured based on femtosecond Z-scan.Our results suggest that Cs_(2)TiBr_(6)NCs can be extensively applied in the field of optoelectronics,owing to its excellent carrier dynamics and nonlinear optical properties.