Solid–Liquid Hybrid‐State Organic Lens for Highly Efficient Deep Ultraviolet Light‐Emitting Diodes

Abstract

Deep ultraviolet light‐emitting diodes (DUV‐LEDs) are considered to be the most promising ultraviolet light sources for effective and fast sterilization under the worldwide spread of the coronavirus disease (COVID‐19). However, it reminds challenging to promote the light extraction of DUV‐LEDs owing to the strong DUV light absorption of conventional encapsulation materials. Herein, solid–liquid hybrid‐state gels (SLHGs) to fabricate organic lenses for DUV‐LEDs, which largely enhance the light extraction efficiency without sacrificing the working stability, are proposed. Solid‐state cross‐linked networks of polydimethylsiloxane are used in the SLHG structure to maintain the liquid components of silicone oil and demonstrate excellent formability, DUV transparency (over 90% transmittance in the UVC range), and thermal stability. The radiant power of DUV‐LEDs (275 nm) with the optimized SLHG organic lens is enhanced by 52.5% compared to a commercial quartz lens, achieving a record packaging optical effiency of 1.31 among solid‐state packaging DUV‐LEDs. A sterilization evaluation for SARS‐CoV‐2 demonstrates that the inactivation time can be reduced by ≈25% using the SLHG organic lens. Consequently, herein, a feasible and effective method to enhance the optical performance of DUV‐LEDs and advance their promising potential for disinfection applications is provided.