Extremely Flexible Indium‐Gallium‐Zinc Oxide (IGZO) Based Electronic Devices Placed on an Ultrathin Poly(Methyl Methacrylate) (PMMA) Substrate

Abstract

deformation is highly recommended for wearable electronics placed on any textile products and/or hand gloves. [20,21] In general, the substrate having the electronic devices plays an important role in their flexibility. To date, polyimide (PI) has been widely utilized as a flexible substrate due to its excellent dielectric property, and good chemical and thermal stability. [22][23][24][25][26][27] However, commercially available PI is not transparent, which limits its use in display applications, and conformal contact of PI substrate onto nonplanar surfaces such as gloves, flexible poly(vinyl chloride) (PVC) tubes, or cotton by using a glue is impractical.To attain both high flexibility and conformal contact of electronic devices, researchers have designed free-standing organic devices, in which a polymer dielectric layer (e.g., polystyrene, polyacrylonitrile, polylactide) or organic active layer (e.g., pentacene) itself acts as a substrate. [28][29][30][31] Zhang et al. fabricated freestanding pentacene field effect transistors (FETs) by utilizing a polyacrylonitrile dielectric layer to hold the device components and attached it onto rough or even sharp substrates. [32] However, as semiconducting polymers are not stable under atmospheric conditions, [33,34] metal oxide-based electronic devices [35][36][37] using thin inorganic semiconductor layers, such as SnO 2 , ZnO, In-Ga-ZnO, MoO 3 , and TiO 2 , are utilized; however, the thin metal oxide layers cannot endure physical strain greater than 1%, while being bent and twisted. [38] In fact, the physical strain (S) acting on the thin metal oxide layer while being bent can be controlled by substrate thickness, which is determined by a simple formula S = d/2r ("d" is the substrate thickness, and "r" is the bending radius).Therefore, metal oxide-based electronic devices placed on top of an ultrathin organic substrate have been pursued to have less physical strain for ultraflexibility. [39][40][41][42][43] Han et al. engineered a foldable indium tin oxide (ITO)-coated glass platform composed of thick and nondeformable parts surrounded by thin and foldable glass, which was selectively etched down to 5 µm, and successfully obtained a foldable substrate without any device failure. [39] Hassan et al. utilized a thin Al 2 O 3 substrate to fabricate flexible metal oxide-based H 2 sensors. [40] Kim et al. fabricated In-Ga-ZnO TFTs on a 1.5 µm thick polyimide substrate and demonstrated its bendability at a bending radius down to 0.25 mm. [41] The flexibility of metal oxide-based electronic devices is severely limited by the thickness of their substrate. To enhance the flexibility of semiconducting metal oxide-based electronic devices, a new and simple way to fabricate indium-gallium-zinc oxide (IGZO)-based electronic devices on an ultrathin (1.9 µm) poly(methyl methacrylate) (PMMA) substrate is introduced. The PMMA layer spin-coated on an unmodified glass slide has no chemical interactions at the interface, resulting in weak adhesion. Therefore, the PMMA layer with the devices...

Organic/Inorganic Hybrid Top-Gate Transistors with Ultrahigh Electron Mobility via Enhanced Electron Pathways

“…Further, the Al-capped flexible device shows excellent mechanical stability even for a small radius of curvature of 1 mm (Figure S7). Despite the prototype device being fabricated without a buffer layer, our flexible device shows superior bending reliability even under severe bending conditions compared to other oxide-based flexible devices, − as shown in Figure d. Our polymer dielectric device exhibits robust properties on the flexible substrate, which can be attributed to the high modulus of elasticity of the PPx-C dielectric layer.…”

Thin-film electronics on active substrates: review of materials, technologies and applications

“…(e) Highly stretchable hydrogel-ecoflex bilayer can be elongated up to 1780% of strain [46]. [53,82,84,99,114,115], polyethylene terephthalate (PET) [41,98,[116][117][118][119][120], polyethylene naphthalate (PEN) [92,121], and polymethyl methacrylate (PMMA) [29,122].…”

Metal-Oxide Nanomaterials Synthesis and Applications in Flexible and Wearable Sensors

“…Employing a nanomaterial as a catalyst is a widely used method to improve the sensing performance of MON-based flexible gas sensors. Noble metals such as Pd, Ag, and Pt ,, are well-known as dissociation catalysts for gases including H 2 , , NO 2 , and O 2 . , These noble metal NP catalysts were exploited to detect NO 2 , , H 2 , , and EtOH Figure m shows the catalysis of Pt NPs in the EtOH sensing process of In 2 O 3 .…”

“…Noble metals such as Pd, 196 Ag, 195 and Pt 37 , 150 , 197 are well-known as dissociation catalysts for gases including H 2 , 150 , 196 NO 2 , 197 and O 2 . 37 , 195 These noble metal NP catalysts were exploited to detect NO 2 , 195 , 197 H 2 , 150 , 196 and EtOH. 37 Figure 8 m shows the catalysis of Pt NPs in the EtOH sensing process of In 2 O 3 .…”