In Situ Halide Vacancy Tuning of Low-Dimensional Lead Perovskites to Realize Multiple Adjustable Luminescence...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photophysics

Background:

• Surface defects significantly impact perovskite photophysical properties and optoelectronic device performance.
• Current defect passivation methods improve luminescent efficiency but lack comprehensive optimization via defect chemistry.

Purpose of the Study:

• To demonstrate a defect engineering strategy for tunable luminescence in 0D perovskite single crystals.
• To achieve simultaneous modification of multiple luminescent properties by controlling bromide vacancy concentration.

Main Methods:

• Fabrication of [DADPA]PbBr5 single crystals with controlled crystallization environments.
• Spectroscopic investigations (photoluminescence, time-resolved photoluminescence).
• First-principles calculations to understand defect-property relationships.

Main Results:

• Tunable luminescence from broadband blue-white to narrow green emission (445-535 nm) by diminishing bromide vacancies (VBr).
• Significant increase in quantum yields from 3.7% to 80.8% and extended lifetime from 5.4 to 57.7 ns.
• Reduced VBr narrows bandgap, inhibits nonradiative recombination, and enhances bound exciton emission.

Conclusions:

• Defect engineering via VBr reduction offers a universal strategy for multi-dimensional luminescence control in perovskites.
• This approach enhances photoluminescent performance and opens avenues for advanced optoelectronic applications.
• The strategy is extendable to other perovskite systems for broad applicability.