Beyond Illumination: Multifunctional Capabilities of a Near-Ultraviolet Multiple Quantum Well Diode Array.

InGaN/GaN systems are commonly employed for designing near-ultraviolet (UV) light-emitting diodes (LEDs) due to their excellent quantum efficiency and tunable emission wavelengths. However, existing studies predominantly focus on the emission-related functionalities of near-UV LEDs, such as photopolymerization and anti-counterfeiting. This work breaks through the conventional limitation of using these diodes solely as emitters by innovatively designing and demonstrating a 4 × 4 array integrated with 16 near-UV multiple quantum well (MQW) diodes operating at 395-405 nm, exhibiting multifunctional capabilities. When in emission mode, the array performs traditional anti-counterfeiting and UV curing tasks. When in detection mode, the array acts as a photodetector, detecting externally stimulated pixels and enabling optical image input and character recognition via a convolutional neural network (CNN) with an accuracy exceeding 96%. During content display, the non-emitting pixels are repurposed for multiple-input multiple-output (MIMO) near-UV wireless optical communication (WLC), achieving per-pixel data rates up to 40 kHz. Moreover, the array's robustness under strong ambient sunlight was experimentally validated. The integration of these functionalities offers new perspectives and technological solutions for near-UV MQW diode applications, not only in conventional roles, but also in advanced areas such as covert optical input and anti-interference WLC.