Fundamentals of Organic Neuromorphic Systems

Table of contents

Introduction                                                                                                                7

Determination of memristor                                                              11

Mnemotrix                                                                                                      13

First mention about the experimental realization of memristor                   13

Inorganic memristive devices                                                             15

Memristive devices with organic materials                                       21

Chapter 2: Organic memristive device                                                                       28

2.1.      Basic materials                                                                                               28

2.2.      Structure and working principle of the device                                               30

2.3.      Electrical characteristics of the device                                                           32

2.4.      Device working mechanism                                                                            39

            2.4.1.   Spectroscopy                                                                                       40

            2.4.2.   X-ray fluorescence                                                                              49

2.5.      Electrical characteristics in a pulse mode                                                       54

2.6.      Optimization of properties and stability of the device                                  58

            2.6.1.   Stability of organic memristive device properties                              59

            2.6.2.   Optimization of the device architecture                                            61

            2.6.3.   Role of the electrolyte                                                                        65

2.7.      Organic memristive devices with channels, formed by Layer-by-Layer technique 69

Chapter 3: Oscillators based on organic memristive devices            74

Chapter 4: Models                                                                                                      81

4.1.      Phenomenological model                                                                               82

4.2.      Simplified model of the organic memristive device function             90

4.3.      Electrochemical model                                                                                   93

4.4.      Optical monitoring of the resistive states                                                      102

Chapter 5: Logic elements and neuron networks                                           107

5.1.      Logic elements with memory                                                             107

            5.1.1.   Element "OR" with memory                                                               108

            5.1.2.   Element "AND" with memory                                                110

            5.1.3.   Element "NOT" with memory                                                113

            5.1.4.   Comparison of logic elements with memory, based on organic and inorganic memristive devices                                                                                    114

5.2.      Perceptrons                                                                                                     118

            5.2.1.   Single layer perceptron                                                                       119

Chapter 6: Neuromorphic systems                                                                 130

6.1.      Learning of circuits, based on a single memristive device                 130

            6.1.1.   DC mode                                                                                             130

            6.1.2.   Pulse mode                                                                                         134

6.2.      Training of networks with several memristive elements                               137

6.3.      Training algorithms                                                                                        140

6.4.      Electronic analog of the part of the nervous system of pond snail Lymnaea stanìgnalis                                                                                                                  149

            6.4.1.   Biological benchmark                                                             150

            6.4.2.   Experimentally realized circuit, mimicking the architecture and properties of the pond snail nervous system part                                                               151

6.5.      Cross-talk of memristive devices during pathways formation process         156

6.6.      Effect of noise                                                                                     161

6.7.      Frequency driven short-term memory and long-term potentiation  164

6.8.      Spike Timing Dependent Plasticity (STDP) learning in memristive systems 169

            6.8.1.   STDP in circuits with polyaniline-based memristive devices 170

            6.8.2.   STDP in circuits with parylene-based memristive devices     174

6.8.3.   Classic conditioning of polyaniline-based memristive devices systems 178

6.8.4.   Classic conditioning of parylene-based memristive devices systems 182

6.9.      Coupling with living beings                                                                             184

Chapter 7: 3D systems with stochastic architecture                                      192

7.1.      Free-standing fibrillar systems                                                                       192

7.2.      Stochastic networks on frames with developed structure                196

7.3.      3D stochastic networks, based on phase separation of materials    200

            7.3.1.   Stabilized gold nanoparticles                                                  200

            7.3.3.   Fabrication of 3D stochastic network                                     209

            7.3.4.   Training of stochastic 3D network, based on phase separation of materials 211

            7.3.5.   Evidence of 3D nature of the realized stochastic system                   215

7.4.      Modeling of adaptive electrical characteristics of stochastic 3D network 218

            7.4.1.   Single memristive device                                                                    220

            7.4.2.   Structure of the network                                                                    222

            7.4.3.   Network dynamics                                                                              223

            7.4.4.   Modeling of experimental results, obtained on 3D stochastic networks 224

Conclusions                                                                                                                 232

References