Functional light diffusers based on hybrid CsPbBr$_3$/SiO$_2$ aero-framework structures for laser light illumination and conversion

TL;DR

This paper introduces a hybrid CsPbBr₃/SiO₂ aero-framework structure that effectively diffuses, converts, and manages heat from high-power laser light, advancing laser-based solid-state lighting technology.

Contribution

It presents a novel porous SiO₂ microtube framework functionalized with halide perovskite QDs for efficient light diffusion, color conversion, and thermal management at high laser powers.

Findings

Reduces speckle contrast significantly

Enables stable color conversion under high laser power

Improves thermal dissipation and QD stability

Abstract

The new generation of laser-based solid-state lighting (SSL) white light sources requires new material systems capable of withstanding, diffusing and converting high intensity laser light. State-of-the-art systems use a blue light emitting diode (LED) or laser diode (LD) in combination with color conversion materials, such as yellow emitting Ce-doped phosphors or red and green emitting quantum dots (QD), to produce white light. However, for laser-based high-brightness illumination in particular, thermal management is a major challenge, and in addition, a light diffuser is required to diffuse the highly focused laser beam. Here, we present a hybrid material system that simultaneously enables efficient, uniform light distribution and color conversion of a blue LD, while ensuring good thermal management even at high laser powers of up to 5W. A highly open porous (> 99%) framework structure of hollow SiO$_2$ microtubes is utilized as an efficient light diffuser that can drastically reduce speckle contrast. By further functionalizing the microtubes with halide perovskite QDs (SiO$_2$@CsPbBr$_3$ as model system) color conversion from UV to visible light is achieved. Under laser illumination, the open porous structure prevents heat accumulation and thermal quenching of the QDs. By depositing an ultrathin (~ 5.5 nm) film of poly(ethylene glycol dimethyl acrylate) (pEGDMA) via initiated chemical vapor deposition (iCVD), the luminescent stability of the QDs against moisture is enhanced. The demonstrated hybrid material system paves the way for the design of advanced and functional laser light diffusers and converters that can meet the challenges associated with laser-based SSL applications.