Highly stable wavelength converting composite based on sol–gel derived siloxane-encapsulated luminescent nanocrystals

Luminescent nanocrystals (NCs) have emerged as the high-performance wavelength converting materials in next-generation displays and energy conversion devices due to their unique optophysical properties, such as large Stokes or anti-Stokes shifts, narrow emission bandwidth, and tunable bandgap depending on size or composition. However, poor long-term stability in high temperature and humidity remains a critical issue for device applications. This instability is primarily due to irreversible changes in surface ligands or chemical structures/compositions when exposed to various severe environments. Various strategies have been reported to address these issues, such as the formation of inorganic shell layers and the fabrication of polymer-based nanocomposites. Although these strategies have improved stability, they exhibit degraded properties during long-term aging. Recently, sol–gel derived siloxane hybrid materials have been introduced to achieve stability for various NCs under actual operating conditions of displays and optoelectronic devices. This review will address recent progress in developing siloxane-encapsulated NCs with high stability in high temperature/humidity and under continuous light exposure. It will also introduce results on enhancing the environmental stability of various NCs, including lanthanide-doped transition metal-based NCs, semiconducting NCs, and metal halide perovskite NCs, as well as demonstrations of reliable devices.

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