Light Controlled Memristors And Artificial Optoelectronic Synapses Based On MEH-PPV:PCBM Bulk Heterojunction

Artificial optoelectronic synapses that integrate optical sensing and synaptic functions exhibit significant advantages in processing visual information and completing complex learning,recognition,and memory.Some progress has been made in simulating the dynamic behavior of photonic synapses based on different material systems,such as excitatory post-synaptic current,paired-pulse facilitation,spike timing dependent plasticity,long-term potentiation/depression,and the transition from short-term memory to long-term memory.The use of various synaptic plasticity of synaptic devices can be applied to different scenes,including digital recognition,image memory,color and pattern recognition,object classification,adaptive perception and logical operation,making photonic synaptic devices have potential application prospects in the field of intelligent robots and wearable smart chips.Currently,the reported optical synaptic devices mainly focus on the simple current responses to varying degrees caused by different wavelengths,intensities,and frequencies of optical signals.The functional implementation forms are relatively single and unstable,and they have not been able to simulate dynamically changing synaptic behaviors such as habituation and sensitization.However,achieving multi-functional and complex neural morphology behavior simulation is an inevitable trend in the future development of artificial intelligence.Therefore,it is necessary to explore more synaptic devices with new materials and structures that can improve and achieve multifaceted synaptic behavior,in order to process complex and ever-changing sensory information.For this reason,this thesis proposes to use the bulk heterojunction made of MEH-PPV and PCBM as the functional layer,and mutually doped them with different content ratios to build vertical and planar light regulated memristor respectively.The main research content and achievements are as follows:1.The vertical bulk heterojunction memristor based on the MEH-PPV: PCBM mixed films with different mass concentration ratios was prepared by mixing the MEH-PPV: PCBM mixed solutions.After comparing the basic optoelectronic performance with standard devices,it was found that the ideal target device with a MEH-PPV: PCBM mixing ratio of 4:1 is more prominent.This device not only achieves stable and slowly changing resistance behavior,but also achieves long-term enhancement/suppression of voltage regulation,and exhibits excellent spike voltages dependent plasticity.In addition,the working mechanism of the memristor and the photoinduced charge transfer behavior are analyzed through electrical phenomena and fitting as well as the conductivity behavior of photoelectric co adjustment.2.The optimized vertical memristor was used to simulate a variety of synaptic plasticity jointly regulated by light and electricity,including excitatory post-synaptic current,transformation from short-term plasticity to long-term plasticity,learning-forgetting characteristics,paired-pulse facilitation,post-tetanic potentiation and adjustable conversion of habituation/sensitiation.The device also showed excellent spike rates dependent plasticity.In addition,by utilizing the spike rates dependent plasticity of the device’s light regulation,the pattern recognition and memory functions in the human visual nervous system were successfully simulated,providing a potential optoelectronic component for processing visual system information in the field of artificial intelligence.3.By changing the device structure and using a research method similar to vertical devices to optimize the selection of planar bulk heterojunction devices,the MEH-PPV: PCBM mixing ratio of the optimized device is 6:1.The device has successfully simulated a variety of optoelectronic controlled synaptic behaviors,including excitatory post-synaptic current,spike voltages dependent plasticity,learning-forgetting and paird-pulse facilitation,as well as spike rates dependent plasticity.Moreover,by utilizing the optoelectronic control characteristics of the device,the "AND" gate logic operation for both optical and electrical dual input control has been successfully achieved.This work provides a new type of optoelectronic integrated component for the construction of optoelectronic integrated circuits,and provides a research direction for solving the integration degree of circuits.