A flexible capacitive photoreceptor for the biomimetic retina

Neuromorphic vision sensors have been extremely beneficial in developing energy-efficient intelligent systems for robotics and privacy-preserving security applications. There is a dire need for devices to mimic the retina’s photoreceptors that encode the light illumination into a sequence of spikes to develop such sensors. Herein, we develop a hybrid perovskite-based flexible photoreceptor whose capacitance changes proportionally to the light intensity mimicking the retina’s rod cells, paving the way for developing an efficient artificial retina network. The proposed device constitutes a hybrid nanocomposite of perovskites (methyl-ammonium lead bromide) and the ferroelectric terpolymer (polyvinylidene fluoride trifluoroethylene-chlorofluoroethylene). A metal-insulator-metal type capacitor with the prepared composite exhibits the unique and photosensitive capacitive behavior at various light intensities in the visible light spectrum. The proposed photoreceptor mimics the spectral sensitivity curve of human photopic vision. The hybrid nanocomposite is stable in ambient air for 129 weeks, with no observable degradation of the composite due to the encapsulation of hybrid perovskites in the hydrophobic polymer. The functionality of the proposed photoreceptor to recognize handwritten digits (MNIST) dataset using an unsupervised trained spiking neural network with 72.05% recognition accuracy is demonstrated. This demonstration proves the potential of the proposed sensor for neuromorphic vision applications.

Blending Ratio Effect of ZnPc/ZnO Hybrid Nanocomposite on Surface Morphology and Structural Properties

Recently, organic/inorganic hybrid nanocomposites being the future in electronic applications. In this paper, we have investigated hybrid nanocomposite zinc phthalocyanine (ZnPc)/zinc oxide nanoparticles (ZnO). ZnPc/ZnO hybrid nanocomposites were prepared with different ratios (wt/wt) (1/0), (0/1), (0.75/0.25), (0.5/0.5), (0.25/0.75), and, deposited on glass substrates by spin coating technique. X-Ray diffraction investigate the structural of ZnPc/ZnO thin films and studied the morphological properties using field emission scan electron microscopy, the surface of ZnPc/ZnO hybrid nanocomposites shows the presence of nanorod-like structures represented the organic material (ZnPc) and spherical nanoparticles for (ZnO), that is depending on the ratio of the blend. In ratio (0.5/0.5) we get the preferred homogeneous surface between like-nanorod and spherical shapes were show various properties from pure compounds which used to prepare the blend. The distribution of ZnO nanoparticles on ZnPc particles nanorods led to the disappearance feature of ZnO morphological characterize and ZnPc decorated was dominated on the hybrid nanocomposite structure.