A low-threshold mechanoluminescence platform for broadband NIR emission and obstruction-penetrating optical communication

Abstract

Broadband near-infrared (NIR) luminescent materials are highly sought after for next-generation optoelectronics under dim or invisible conditions, yet simultaneously achieving broadband NIR emission, strong low-threshold mechanoluminescence (ML), and self-recoverable mechano-optical conversion in a single material remains a formidable challenge. Here, we report a Cr 3+ /Yb 3+ codoped LiGa 5 O 8 phosphor that enables broadband NIR emission (650–1100 nm) and low-threshold ML. The emission originates from Cr 3+ d-d transitions and is further extended via energy transfer to Yb 3+ ions. Notably, the phosphor exhibits instantaneous ML activation under ultralow force (∼1.1 N) without pre-irradiation, demonstrating a timely and self-recoverable mechano-optical conversion. By integrating the phosphor into NIR phosphor-converted light emitting diodes (pc-LEDs), stable optical signal transmission through obstructed environments is achieved, enabling non-line-of-sight (NLOS) communication. This work provides a viable strategy for coupling low-threshold ML with broadband NIR emission for sensing and communication applications.