Molecular template growth of organic heterojunctions to tailor visual neuroplasticity for high performance phototransistors with ultralow energy consumption. Issue 5 (3rd March 2023)

• Record Type: Journal Article
• Authors: Ercan, Ender; Hung, Chih-Chien; Li, Guan-Syuan; Yang, Yun-Fang; Lin, Yan-Cheng; Chen, Wen-Chang
• Is Part Of: Nanoscale horizons. Volume 8:Issue 5(2023)
• Page Start: 632
• Page End: 640
• Publication Date: 2023-03-03
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d2nh00597b
• Languages: English
• ISSNs: 2055-6756

Abstract

Abstract : The molecular template growth of the heterojunction was studied to tailor neuroplasticity that exhibits a high pair-pulse facilitation index of ~206%, and ultralow energy consumption of 0.54 fJ to mimic human-like optical synapse and memory functions. Abstract : The optical and charge transport properties of organic semiconductors are strongly influenced by their morphology and molecular structures. Here we report the influence of a molecular template strategy on anisotropic control via weak epitaxial growth of a semiconducting channel for a dinaphtho[2, 3- b :2′, 3′- f ]thieno[3, 2- b ]thiophene (DNTT)/ para -sexiphenyl ( p -6P) heterojunction. The aim is to improve charge transport and trapping, to enable tailoring of visual neuroplasticity. The proposed phototransistor devices, comprising a molecular heterojunction with optimized molecular template thickness, exhibited an excellent memory ratio ( I ON / I OFF ) and retention characteristics in response to light stimulation, owing to the enhanced orientation/packing of DNTT molecules and a favorable match between the LUMO/HOMO levels of p -6P and DNTT. The best performing heterojunction exhibits visual synaptic functionalities, including an extremely high pair-pulse facilitation index of ∼206%, ultralow energy consumption of 0.54 fJ, and zero-gate operation, under ultrashort pulse light stimulation to mimic human-like sensing, computing, and memory functions. An array of heterojunction photosynapses possess a high degree of visual pattern recognition and learning, to mimic the neuroplasticity of human brain activities through a rehearsal learning process. This study provides a guide to the design of molecular heterojunctions for tailoring high-performance photonic memory and synapses for neuromorphic computing and artificial intelligence systems.