On-device Data Encryption in Visible Light Communication of Quantum Dot Permeable Electrode Light-Emitting Triodes

Visible light communication (VLC) is a promising technology to alleviate data traffic issues and spectrum allocation competition by offering free and wide bandwidth in the visible light range (400 ~ 800 THz). Traditional optoelectronic devices, such as light-emitting diodes (LEDs), are crucial building blocks for constructing novel VLC systems. However, two-terminal devices face fundamental limitations in providing additional functionality and achieving high-density integration. To address these challenges, we incorporated a third permeable electrode (PE) between vertically stacked LED and capacitor units. This three-terminal device architecture of permeable electrode light-emitting triodes (PeLETs) achieves a maximum external quantum efficiency (EQE) of 17.4%, and luminance exceeding 29000 cd m^-2. We precisely elucidate and reveal the intricate interplay between the RC circuit and the charge injection process by using modified three-terminal transient electroluminescence measurements of PeLETs. In addition, expanded functionalities enabled by the PE allow simultaneous modulation of two input data using optical logic gates, such as ‘AND’, ‘OR’, and ‘Negative Implication (NIMP) logic gates, within a single device. The PeLETs enhance data throughput and the transmission capacity through dual-channel communication via the optical logic ‘OR’ gate. Furthermore, by using optical logic gates, we demonstrated on-device data encryption by adapting a concept of an interference layer during the data transmission process in PeLETs, where decryption required specific information on channel selection and logic gate configurations. The single-device data modulation using PeLETs suggests a novel concept of on-device data encryption for next-generation, highly secure data communication systems.