(744i) Conductive, Large-Area, and Continuous 7,7,8,8-Tetracyanoquinodimethane@HKUST-1 Thin Films Fabricated Using Solution Shearing

Most metal-organic frameworks (MOFs) are insulating due to their porosity and redox-inactive organic components. The electrical conductivity of the prototypical MOF, HKUST-1, can be tuned by infiltrating a small molecule organic semiconductor 7,7,8,8-tetracyanoquinododimenthane (TCNQ) into the HKUST-1 pores, creating TCNQ@HKUST-1. However, the current processes of creating TCNQ@HKUST-1 films have many roadblocks such as slow crystallization rates which limit high throughput production, and the formation of Cu(TCNQ) as a byproduct, which affects the degree of electrical conductivity and degrades the chemical structure of HKUST-1. In this work, we show that HKUST-1 films can be rapidly synthesized over large areas with consistent thickness and no pinholes via a meniscus-guided coating technique called solution shearing. The subsequent pore activation process and TCNQ impregnation can be completed via solvent exchange to minimize the formation of Cu(TCNQ) byproduct, and we obtain an increase of electrical conductivity of the solution sheared TCNQ@HKUST-1 thin films over seven orders of magnitude, reaching a maximum value of 2.42 Х 10^-2 S m^-1 when TCNQ is incorporated for 10 days. The conductivity of solution sheared TCNQ@HKUST-1 is higher than previous results for films formed by high-pressure pelletization of TCNQ@HKUST-1. We show that solution shearing can produce large area thin films rapidly and reduce the formation of grain boundaries better than pelletization, allowing for large area electronics with both charge transport and porosity for applications as sensors and electronics.