Biomimetic nanocluster photoreceptors for adaptive circular polarization vision

Nanoclusters with atomically precise structures and discrete energy levels are considered as nanoscale semiconductors for artificial intelligence. However, nanocluster electronic engineering and optoelectronic behavior have remained obscure and unexplored. Hence, we create nanocluster photo-receptors inspired by mantis shrimp visual systems to satisfy the needs of compact but multi-task vision hardware and explore the photo-induced electronic transport. Wafer-scale arrayed photoreceptors are constructed by a nanocluster-conjugated molecule heterostructure. Nanoclusters perform as an in-sensor charge reservoir to tune the conductance levels of artificial photoreceptors by a light valve mechanism. A ligand-assisted charge transfer process takes place at nanocluster interface and it features an integration of spectral-dependent visual adaptation and circular polarization recognition. This approach is further employed for developing concisely structured, multi-task, and compact artificial visual systems and provides valuable guidelines for nanocluster neuromorphic devices. Artificial vision systems (AVSs) that adapt to complex environments and fulfill multi-task photoperception have become increasingly desired in facial recognition, autonomous vehicles, and visual prostheses. State-of-the-art AVSs are not as exquisite as their biology prototypes in terms of structure simplicity, self-regulation, and multi-functions. For example, photoadaptation devices and neuromorphic phototransistors are designed either with sophisticated multilayers or integration of detectors and processors, increasing manufacturing costs and difficulty. It remains a critical challenge to compact a multiple of functions into an all-in-one single cell. Visual systems of mantis shrimps are equipped with 16 photoreceptors to fulfill multiple tasks of color recognition, adaptive vision, and circularly polarized light (CPL) perception. Though aforementioned functions have discretely been enabled by panchromatic absorbing materials, circularly polarized molecule-assemblies or chiral compounds and photoadaptative devices. It is of high theoretical and practical value to develop bioinspired hardware that enables parallel processing of color recognition, tunable adaptation, CPL perception, and multi-state readout. Nanoclusters are precise metal atoms coordinated by alternative protective ligands and this unique structure allows tunable physical properties, such as discrete energy levels and sizable bandgaps due to quantum size effects. Additionally, nanoclusters possess excellent photon-to-electron conversion, thus being advantageous for the construction of artificial photoreceptors. Herein, inspired by mantis shrimps, we demonstrate an artificial nanocluster photoreceptor (ACP) array based on a heterostructure formed by chiral nanoclusters and organic semiconductors.

Wei Wen, Guocai Liu, Xiaofang Wei, Haojie Huang, Chong Wang, Danlei Zhu, Jianzhe Sun, Huijuan Yan, Xin Huang, Wenkang Shi, Xiaojuan Dai, Jichen Dong, Lang Jiang, Yunlong Guo, Hanlin Wang, Yunqi Liu