Surfactant-Induced Solubility Control To Realize Water-Processed High-Precision Patterning of Polymeric Semiconductors for Full Color Organic Image Sensor

Abstract

A fully water-based patterning method for polymer semiconductors was developed and utilized to realize high-precision lateral patterning of various polymers. Water-borne polymer colloids, wherein hydrophobic polymers are dispersed in water with the assistance of surfactant molecules, possess a hydrophilic surface when printed onto a substrate. When this surface is exposed to a washing molecule, the surface of the polymer film recovers its original hydrophobic nature. Such surfactant-induced solubility control (SISC) enables environmentally benign, water-processed, and high-precision patterning of various polymer semiconductors with totally different solubilities, so that fully water-processed polymer organic image sensors (OISs) can be realized. B-/G-/R-selective photodiodes with a pixel size of 100 μm × 100 μm were fabricated and patterned by this water-based SISC method, leading to not only high average specific detectivity values (over 1012 Jones) but also narrow pixel-to-pixel deviation. Thanks to the superiority of the SISC method, we demonstrate the image capturing ability of OISs without B-/G-/R-color filters, from a fully water-based fabrication process.

Materials Chemistry, Device Engineering, and Promising Applications of Polymer Transistors

“…A photon can generate an exciton, a bound pair of an electron and a hole, and the charge carriers can then be separated and swept to the electrodes under an electric field. This phenomenon can be useful in photodetectors …”

Wavelength‐Selective Organic Photodetectors

“…A nice demonstration of the advantages of organic semiconductors in terms of processing and absorption characteristics is the realization of a fully water‐processed polymer image sensor by Sim et al [ 17 ] Through the use of a water‐borne colloidal solution, the organic materials can be deposited on the hydrophilic sites on the substrate, which were formed in the desired pattern by an oxygen plasma treatment through a shadow mask. In this way, RGB‐selective PDs with detectivities in the order of 10 12 Jones (Hz −1/2 cm W −1 ) and a pixel size of 150 µm × 150 µm ( Figure a) were fabricated without the need for additional color filters.…”

“…Reproduced with permission. [ 17 ] Copyright 2020, American Chemical Society. b) Illustration of the device architecture with a photograph of an organic spectrophotometer used to measure the transmittance spectrum of water.…”

“…Figure shows D * values extracted from 43 papers reporting narrow‐band OPDs from the year 2012 onwards with an FWHM value of a maximum of 150 nm. [ 4,17–21,25,28,30–34,38–67 ] To get an overview of the current status of the field, it is instructive to plot D * as a function of peak EQE value, J d , and design wavelength. It is important to mention that not in all of these papers the noise currents have been directly measured and D * has often been calculated using , given by Equation (2).…”

End‐Group Functionalization of Non‐Fullerene Acceptors for High External Quantum Efficiency over 150 000% in Photomultiplication Type Organic Photodetectors

“…[ 2–5 ] Due to these advantages, a variety of methods to realize organic semiconductor‐based image sensors have been reported. [ 6–12 ] Among these, photomultiplication‐type OPDs (PM‐OPDs) are receiving increasing attention due to their exceptionally high external quantum efficiency (EQE). [ 13–18 ] Photomultiplication is an extrinsic photocurrent amplification mechanism in which trapped charge carriers (e.g., electrons) can induce the injection of the counter charge carriers (e.g., holes) by tunneling from the external circuit, which differs from the intrinsic multiexciton generation mechanism.…”