Capillary-Bridge Mediated Assembly of Conjugated Polymer Arrays toward Organic Photodetectors

Large-scale patterning of high-quality organic semiconductors is crucial for the fabrication of optoelectronic devices with high efficiency and low cost. Yet, owing to the uncontrollable dewetting dynamics of organic liquid in conventional solution patterning techniques, large defect density of organic architectures is inevitable, which is detrimental to the device performance. To address this challenge, herein a capillary-bridge-mediated assembly technique is developed for regulating the dewetting process, yielding large-scale 1D microstructure ordered arrays. The 1D arrays organic photodetectors exhibit a high optoelectronic performance of light on/off ratio exceeding 100, responsivity of 3.24 A W⁻¹, detectivity of 3.20 × 10¹¹ Jones and fast response speed, showing a great improvement compared with spin-coated membrane devices. In addition, the significant enhancement of the device photodetection under the electronic field modulation is investigated by applying a back-gate voltage and explained with the photocurrent predominating in the OFF state and the neglected thermocurrent and tunneling current promoting in the ON state of the phototransistor devices. The research offers a new insight for the facile fabrication of large-scale integrated photodetectors and other organic devices based on patterned conjugated polymers.