ORGANIC IONO-OPTOELECTRONICS

Conjugated polymers are organic macromolecules that are characterized by a backbone chain of alternating double- and single-bonds. This alternating pattern results in delocalized π electronic systems, contributing to electronic conduction. In the solid state, conjugated polymers exhibit weak intermolecular interactions, rendering them soft nature in comparison to many of their inorganic counterparts, such as silicon, which consist of ‘hard' three-dimensional networks of rigid covalent bonds. In electrolyte, this weak intermolecular interaction creates free pathways for ion penetration and facilitates mixed ionic-electronic coupling. The ionic-electronic coupling of conjugated polymers impacts nearly all their properties, including light absorption, electronic conductivity, mechanical strength, etc.

Organic iono-optoelectronics represent a class of devices where the ionic-electronic coupling in conjugated polymers can be synergistically or independently controlled by light irradiation and electrical voltage, enabling multimode electronic and optical functionalities. This dissertation explores two types of organic iono-optoelectronic devices: electrochromic devices and artificial eyes. In electrochromic devices, the ionic-electronic coupling is dynamically modulated by electrical voltage, which induces optical changes of conjugated polymers for applications in information visualization, thermal management, camouflage, etc. Conversely, artificial eyes utilize optical stimulation to tailor the electronic-ionic coupling, with electrical potential changes serving as readout. This paradigm shift opens the door to the development of light-driven biomedical electronics and intelligent visual systems. In the development of electrochromic devices, we introduce two strategies that expand the color palette and enhance the optical control of electrochromic devices, promoting their potential use in display and camouflage. In the development of artificial eye development, we introduce an electrochemical transistor device with integrated functions of light perception, memorization, and recognition by leveraging photon-modulated ion-electronic coupling. This device demonstrates great potential for intelligent visual systems and promises future optoelectronic neural interfaces.