Journal Article

Mixed-flow design for microfluidic printing of two-component polymer semiconductor systems

Mukherjee, Subhrangsu, Stoddart, J. Fraser, Marks, Tobin J., Feng, Liang-Wen, Strzalka, Joseph, Wang, Binghao, Wang, Gang, Fabiano, Simone, Chen, Yao, Shen, Dengke, Zhu, Meifang, Melkonyan, Ferdinand S., Huang, Wei, DeLongchamp, Dean M., Zheng, Ding, Yan, Jinhui, Facchetti, Antonio

2020

Overview

The rational creation of two-component conjugated polymer systems with high levels of phase purity in each component is challenging but crucial for realizing printed soft-matter electronics. Here, we report a mixed-flow microfluidic printing (MFMP) approach for two-component π-polymer systems that significantly elevates phase purity in bulk-heterojunction solar cells and thinfilm transistors. MFMP integrates laminar and extensional flows using a specially microstructured shear blade, designed with fluid flow simulation tools to tune the flow patterns and induce shear, stretch, and pushout effects. This optimizes polymer conformation and semi-conducting blend order as assessed by atomic force microscopy (AFM), transmission electron microscopy (TEM), grazing incidence wide-angle X-ray scattering (GIWAXS), resonant soft X-ray scattering (R-SoXS), photovoltaic response, and field effect mobility. For printed all-polymer (poly[(5,6-difluoro-2-octyl-2H-benzotriazole-4,7-diyl)-2,5-thiophenediyl[ 4,8-bis[5-(2-hexyldecyl)-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-2,5-thiophenediyl]) [J51]:(poly{[N,N′-bis(2-octyldodecyl) naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)}) [N2200]) solar cells, this approach enhances short-circuit currents and fill factors,with power conversion efficiency increasing from 5.20% for conventional blade coating to 7.80% for MFMP. Moreover, the performance of mixed polymer ambipolar [poly(3-hexylthiophene-2,5-diyl) (P3HT):N2200] and semiconducting:insulating polymer unipolar (N2200:polystyrene) transistors is similarly enhanced, underscoring versatility for two-component π-polymer systems. Mixed-flow designs offer modalities for achieving high-performance organic optoelectronics via innovative printing methodologies.

• Publisher: National Academy of Sciences
• Subject: Atomic force microscopy / Benzotriazole / Blade coating / Chemistry / Circuits / Conformation / Design / Dicarboximide / Energy conversion efficiency / ENGINEERING / Flow pattern / Flow simulation / Fluid dynamics / Fluid flow / Heterojunctions / Laminar flow / Microfluidics / Microscopy / Mixed-flow design / Naphthalene / Optoelectronics / Phase purity / Photovoltaic cells / Photovoltaics / Physical Sciences / Polymers / Polystyrene / Polystyrene resins / Printed electronics / Printing / Purity / Semiconducting polymer / Semiconductor devices / Short circuit currents / Short-circuit current / Soft x rays / Solar cells / Thin film transistors / Thin films / Transistors / Transmission electron microscopy / Two-component / X-ray scattering