Integration of synaptic phototransistors and quantum dot light-emitting diodes for visualization and recognition of UV patterns

• Published in: Science advances Vol. 8; no. 41; p. eabq3101
• Main Authors: Seung, Hyojin, Choi, Changsoon, Kim, Dong Chan, Kim, Ji Su, Kim, Jeong Hyun, Kim, Junhee, Park, Soo Ik, Lim, Jung Ah, Yang, Jiwoong, Choi, Moon Kee, Hyeon, Taeghwan, Kim, Dae-Hyeong
• Format: Journal Article
• Language: English
• Published: American Association for the Advancement of Science 14.10.2022
• Subjects: Applied Sciences and Engineering; Materials Science; Physical and Materials Sciences; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abq3101

Synaptic photodetectors exhibit photon-triggered synaptic plasticity, which thus can improve the image recognition rate by enhancing the image contrast. However, still, the visualization and recognition of invisible ultraviolet (UV) patterns are challenging, owing to intense background noise. Here, inspired by all-or-none potentiation of synapse, we develop an integrated device of synaptic phototransistors (SPTrs) and quantum dot light-emitting diodes (QLEDs), facilitating noise reduction and visualization of UV patterns through on-device preprocessing. The SPTrs convert noisy UV inputs into a weighted photocurrent, which is applied to the QLEDs as a voltage input through an external current-voltage–converting circuit. The threshold switching characteristics of the QLEDs result in amplified current and visible illumination by the suprathreshold input voltage or nearly zero current and no visible illumination by the input voltage below the threshold. The preprocessing of image data with the SPTr-QLED can amplify the image contrast, which is helpful for high-accuracy image recognition. The integrated device of synaptic phototransistors and QLEDs facilitates visualization and recognition of UV patterns.