Deep-red emissive colloidal lead-based triiodide perovskite/telluride nanoscale heterostructures with reduced surface defects and enhanced stability for indoor lighting applications

Integrating together the nanostructures of two dissimilar materials into a single architecture can usually gain superior physical properties owing to the strong interaction. Herein, we proposed an epitaxial growth strategy to synthesize lead-based triiodide perovskite/telluride colloidal nanoscale heterostructures (CsPbI3/PbTe CNHs) via a rapid hot-injection method. The as-obtained CNHs exhibited a longer fluorescence lifetime associated with the radiative recombination of charge carriers, compared with the pristine CsPbI3 colloidal nanocrystals (CNCs). This was mainly attributed to the passivation of surface defects achieved by the PbTe component, which could be evidenced by the time-resolved spectroscopic studies. The stability of the CNHs had been improved considerably in comparison with that of pristine CNCs. The theoretical calculations based on density function theory (DFT) further revealed that the strong interaction and high binding energy at the CsPbI3/PbTe interfaces were responsible for the enhancement of α-phase stability. Moreover, the as-prepared CNHs were used as a deep-red emissive phosphor for assembling light-emitting diode (LED) devices, which demonstrated good prospects for broad applications in the field of indoor lighting, such as full-visible-spectrum and plant growth LEDs.