Calcination-Free Liftoff Photolithography of Mixed Dip-Coated Films Consisting of Rare-Earth-Ion-Doped Nanoparticles on Plastic Sheets

Abstract

Introduction Two-dimensional nanofabrication has attracted much attention in various fields such as materials, biotechnology, and information technology. Photolithography 1-5) , electron-beam lithography 6-8) , soft lithography 9-13) and scanning probe force microscopic lithography 14-21) , categorized as top-down technologies, have been used. Nanostructures in block copolymers 22, 23) , Langmuir-Blodgett (LB) films 24-33) and phospholipid monolayers 34-37) have been utilized for patterning functional materials using bottom-up processes. Rare-earth-ion-doped (RE) inorganic phosphor films have attracted much attention for applications in displays, sensors, and emitting devices because of their unique photonics properties, long operating lifetimes compared with organic semiconductors, and good resistance to fading. Upconversion phenomena originate from rare-earth ions doped in low-phonon inorganic materials under stepwise infrared excitations 38, 39). These phenomena have been used for nanofabrication 40) and high-resolution imaging in nonlinear optical fields 41). In addition, the near-infrared (NIR)

Calcination-free micropatterning of rare-earth-ion-doped nanoparticle films on wettability-patterned surfaces of plastic sheets

“…Green and red upconversion luminescence attributed to 2 H 11/2 À 4 I 15/2 , 4 S 3/2 À 4 I 15/2 , and 4 F 9/ 2 À 4 I 15/2 transitions of Er 3+ and near-infrared fluorescence assigned to 2 F 5/2 À 2 F 7/2 transition of Yb 3+ and 4 I 13/2 À 4 I 15/2 transition of Er 3+ are evident. It should be noted that the formation of the RE-nanoparticle films in disk shapes using micromolding in capillaries is difficult because the holes in the molds cannot be connected with each other [26]. These results demonstrate that the RE-nanoparticle films serve as visible and near-infrared emitting devices.…”

“…RE nanoparticle films were fabricated on the whole area of patterned photoresist films on plastic sheets followed by rinsing with acetone for liftoff, resulting in the formation of patterned RE nanoparticle films on plastic sheets [25,26]. Recently, we reported a new calcination-free technique for the direct patterning of RE nanoparticle films by micromolding in capillary which is one of the soft lithography techniques [27].…”

Near Infrared (NIR) Lanthanide Emissive Langmuir–Blodgett Monolayers Formed Using Nd(III) Directed Self-Assembly Synthesis of Chiral Amphiphilic Ligands

“…Having established the ability of 1 and 2 to form 3:1 self-assemblies in the presence of Nd(III), we next investigated their self-assembly formation at an air–water interface by forming Langmuir films. Only a small numbers of examples of lanthanide based Langmuir–Blodgett films (LB-films) made from the use of thermodynamically and kinetically stable lanthanide complexes have been developed to date, − and to the best of our knowledge no examples of NIR emitting LB-films (or NIR luminescent monolayers) have been developed to date, though related systems have been developed, , but such systems have potential applications in sensing, imaging, and telecommunications.…”

Calcination-free micromolding in capillaries for nanopatterning of inorganic upconversion luminescent layers on flexible plastic sheets

“…First, Er 3+ and Yb 3+ codoped Y 2 O 3 nanoparticle films on the whole area of patterned photoresist films on polyethylene terephthalate sheets. After immersion in acetone for the liftoff, the photoresist films and the Y 2 O 3 nanoparticle films on them were removed selectively from the substrates, resulting in the formation of the patterned Y 2 O 3 nanoparticle films [30,31]. Patterned self-assembled monolayers and PDMS molds were used in soft lithography for the calcination-free patterning of the Y 2 O 3 nanoparticle films on indium thin oxide (ITO)/polyethylene 2,6-naphthalate (PEN) sheets with minimized material consumption and reduced fabrication steps [32,33].…”