Work Function Engineering of Electrohydrodynamic-Jet-Printed PEDOT:PSS Electrodes for High-Performance Printed Electronics

Abstract

Poly(3,:poly(4-styrene sulfonate) (PEDOT:PSS) has demonstrated outstanding performance as a charge transport layer or an electrode in various electronic devices, including organic solar cells, organic lightemitting diodes, and organic field-effect transistors (OFETs). The electrical properties of these devices are affected by the contact properties at the PEDOT:PSS−semiconductor junction. In this research, we performed work function (WF) engineering of electrohydrodynamic (EHD)-jet-printed PEDOT:PSS and successfully used it as an electrode to fabricate high-performance OFETs and complementary logic circuits. Two types of PEDOT:PSS materials−one with a high WF (HWF, 5.28 eV) and the other with a low WF (LWF, 4.53 eV)−were synthesized and EHD-jet-printed. The WF of PEDOT:PSS was deterministically modulated by approximately 0.75 eV through simple mixing of the two synthesized PEDOT:PSS materials in various ratios. OFETs fabricated with HWF and LWF PEDOT:PSS electrodes showed excellent electrical properties, including the ON/OFF switching ratio higher than 10 7 and the highest carrier mobility greater than 1 cm 2 •V −1 •s −1 . Furthermore, the HWF and LWF PEDOT:PSS electrodes were integrated to fabricate complementary metal−oxide− semiconductor (CMOS) NOT, NOR, and NAND circuits.

High Precision 3D Printing for Micro to Nano Scale Biomedical and Electronic Devices

“…Among them, PDMS are suitable for EHD printed electronics. Recent studies focus on fabricating flexible pressure and strain sensor array [143,144], ion-gel-based transistor [145], flexible electrodes [146][147][148], organic thin-film transistor (OTFT) [149,150] etc. Although PEDOT: PSS is commonly used in printed electronics, the ink properties, geometrical pattern and array can be further optimized for targeted applications and multi-modal sensor integration.…”

Additive Manufacturing of Conducting Polymers: Recent Advances, Challenges, and Opportunities

“…The printed electrode presented different work function (WF) values, according to the Schottky–Mott rule, to be considered as the next generation of integrated circuits and other multifunctional electronic devices. 93 …”

Strategy for Selective Printing of Gate Insulators Customized for Practical Application in Organic Integrated Devices

“…The use of logic circuits in cheaper and portable electronic products usually require simplified and diversified patterning processes. − Organic electronic materials are regarded as the best candidates to realize such logic circuits because the simple molecular design and solubility control of the organic materials allow optimized ink formulation for various direct patterning processes such as inkjet, screen, and electrohydrodynamic (EHD) printings. ,, For example, highly crystalline conjugated polymer semiconductors were printed entirely on substrates having a large area after considering the molecular design and jetting conditions during the printing process. , Extensive studies that report on the printing of electrodes using direct printing techniques have also been carried out. ,, All these processes that were deposited and patterned in one step contributed to an easy patterning of building blocks for the logic circuits. In parallel with semiconductor and electrode printing, the direct printing of gate insulators (GIs) is an equally important factor that simplifies the fabrication of organic circuits including memory cells, complementary inverters, NAND, and NOR logic gates.…”

“…11−13 Organic electronic materials are regarded as the best candidates to realize such logic circuits because the simple molecular design and solubility control of the organic materials allow optimized ink formulation for various direct patterning processes such as inkjet, screen, and electrohydrodynamic (EHD) printings. 4,5,14 For example, highly crystalline con-jugated polymer semiconductors were printed entirely on substrates having a large area after considering the molecular design and jetting conditions during the printing process. 15,16 Extensive studies that report on the printing of electrodes using direct printing techniques have also been carried out.…”

“…15,16 Extensive studies that report on the printing of electrodes using direct printing techniques have also been carried out. 4,14,17 All these processes that were deposited and patterned in one step contributed to an easy patterning of building blocks for the logic circuits. In parallel with semiconductor and electrode printing, the direct printing of gate insulators (GIs) is an equally important factor that simplifies the fabrication of organic circuits including memory cells, complementary inverters, NAND, and NOR logic gates.…”