Aerosol Jet Printing of Graphene and Carbon Nanotube Patterns on Realistically Rugged Substrates

Abstract

Direct-write additive manufacturing of graphene and carbon nanotube (CNT) patterns by aerosol jet printing (AJP) is promising for the creation of thermal and electrical interconnects in (opto)electronics. In realistic application scenarios, this however often requires deposition of graphene and CNT patterns on rugged substrates such as, for example, roughly machined and surface-oxidized metal block heat sinks. Most AJP of graphene/CNT patterns has thus far however concentrated on flat wafer- or foil-type substrates. Here, we demonstrate AJP of graphene and single walled CNT (SWCNT) patterns on realistically rugged plasma-electrolytic-oxidized (PEO) Al blocks, which are promising heat sink materials. We show that AJP on the rugged substrates offers line resolution of down to ∼40 μm width for single AJP passes, however, at the cost of noncomplete substrate coverage including noncovered μm-sized pores in the PEO Al blocks. With multiple AJP passes, full coverage including coverage of the pores is, however, readily achieved. Comparing archetypical aqueous and organic graphene and SWCNT inks, we show that the choice of the ink system drastically influences the nanocarbon AJP parameter window, deposit microstructure including crystalline quality, compactness of deposit, and inter/intrapass layer adhesion for multiple passes. Simple electrical characterization indicates aqueous graphene inks as the most promising choice for AJP-deposited electrical interconnect applications. Our parameter space screening thereby forms a framework for rational process development for graphene and SWCNT AJP on application-relevant, rugged substrates.

Systematic Design of a Graphene Ink Formulation for Aerosol Jet Printing

“…The combination of these two effects improves resolution–deposition rate trade-offs, which is especially important during printing of high aspect ratio features. This attribute will likely be beneficial for stable deposition on nonplanar substrates, for which AJP’s noncontact operation at a high standoff distance is attractive for conformal electronics and deposition on surfaces with higher roughness than those considered in this work. , Additionally, the conformational changes of the dispersing polymers might be generally exploited during formulation of other inks specifically tailored to AJP.…”

Printed Electronics in Radiofrequency Energy Harvesters and Wireless Power Transfer Rectennas for IoT Applications

“…[135] This technique is free from this limitation due to using a concentrated aerosol jet to print patterns, whose parameters remain stable between the end of the printing nozzle and 10mm toward the substrate. [235,[242][243][244][245] The aerosol jet printing technique is currently broadly investigated-process optimization, [246][247][248][249][250][251][252][253][254][255] characterization of new inks and substrate materials, [256][257][258][259] and process enhancement. [260][261][262][263] As it is a maskless and noncontact technique, it is often considered a potential competitor to inkjet printing.…”

An Aerosol Jet Printed Resistance Temperature Detector‐Micro Hotplate with Temperature Coefficient of Resistance Stabilized by Electrical Sintering

“…Since the commercialization of AJP systems in 2004, [ 10 ] research efforts have been focused on expanding the variety of printable materials, [ 11 ] as well as optimizing the printing process. [ 1,12 ] Aerosol jet compatible conductive materials include metals in nanoparticle, [ 13 ] metallo‐organic, [ 14 ] or inorganic salt [ 15 ] forms, non‐metallic conductors such as carbon nanotubes (CNTs), [ 16 ] graphene, [ 16 ] and PEDOT:PSS. [ 17 ] These materials typically require post‐print sintering or curing to be activated.…”