Theoretical studies
have identified cesium titanium bromide (Cs2TiBr6), a vacancy-ordered double perovskite, as
a promising lead-free and earth-abundant candidate to replace Pb-based
perovskites in photovoltaics. Our research is focused on overcoming
the limitations associated with the current Cs2TiBr6 syntheses, which often involve high-vacuum and high-temperature
evaporation techniques, high-energy milling, or intricate multistep
solution processes conducted under an inert atmosphere, constraints
that hinder industrial scalability. This study presents a straightforward,
low-energy, and scalable solution procedure using microwave radiation
to induce the formation of highly crystalline Cs2TiBr6 in a polar solvent. This methodology, where the choice of
the solvent plays a crucial role, not only reduces the energy costs
associated with perovskite production but also imparts exceptional
stability to the resulting solid, in comparison with previous reports.
This is a critical prerequisite for any technological advancement.
The low-defective material demonstrates unprecedented structural stability
under various stimuli such as moisture, oxygen, elevated temperatures
(over 130 °C), and continuous exposure to white light illumination.
In summary, our study represents an important step forward in the
efficient and cost-effective synthesis of Cs2TiBr6, offering a compelling solution for the development of eco-friendly,
earth-abundant Pb-free perovskite materials.