Site-Isolated Upconversion Nanoparticle Arrays Synthesized in Polyol Nanoreactors

Abstract

A versatile approach for synthesizing Yb 3+ -and Er 3+ -doped NaYF 4 upconversion nanoparticle (UCNP) arrays is presented. The nanoparticles are positioned at precisely defined locations through the tip-directed deposition of polyol nanoreactors and subsequent thermal conversion. This method is based on conducting a solution-phase polyol synthesis in nanometerscale reactors, which provide isolated and confined reaction vessels for the thermal decomposition of a fluoride precursor and the coarsening of fluoride nanoparticles. When the nanoreactors are annealed at 350 °C, the polyol degrades, and the nanoparticles, which exhibit upconversion properties, crystallize. Single nanoparticles are attained in each nanoreactor by tuning the precursor concentration, nanoreactor size, and temperature ramping rate. This strategy enhances the scope of nanostructures that can be synthesized by tip-directed routes and, when combined with massively parallel pen approaches such as polymer pen lithography, provides a generalizable platform for the high-throughput synthesis, screening, and discovery of nanomaterials for photonics and other applications.

Conversion of Classical Light Emission from a Nanoparticle‐Strained WSe2 Monolayer into Quantum Light Emission via Electron Beam Irradiation

“…[38,39] It allows straightforward fabrication of metallic and semiconducting NPs on arbitrary substrates such as SiN x membranes without the need for additional deposition processes or pre-manufactured masks. [40,41] SPBCL of CuO NPs on silicon was chosen due to their simple synthesis by SPBCL, and because CuO does not exhibit any plasmonic or electronic interactions with the WSe 2 flake once passivated with a 10 nm Al 2 O 3 layer deposited via atomic layer deposition (ALD; Figure 1A, see Experimental Section). In a typical experiment, arrays of isolated singular NPs or clusters of NPs were synthesized (see Experimental Section and Figure S1, Supporting Information), followed sequentially by ALD alumina passivation and WSe 2 deposition using polydimethylsiloxane (PDMS)-assisted dry transfer.…”

Molecular Thin Films Enable the Synthesis and Screening of Nanoparticle Megalibraries Containing Millions of Catalysts

“…Single nanoparticles are formed in each nanoreactor by loading the reactors with metal salts followed by annealing. This confined synthesis has been used to make metallic or ionic nanoparticles, , perovskites, and heterostructured nanoparticles, − all with controlled composition and size. Patterns consisting of up to 5 billion identical nanomaterials have been synthesized, showing large area parallel synthesis is highly controllable.…”

Patterning of Molecules/Ions via Reverse Micelle Vessels by Nanoxerography

“…The precise positioning and patterning of functional materials at specific locations pave an important path for the development of advanced nanodevice fabrication, especially in the optoelectronic and biomedical fields. − Molecules/ions are the most basic units of functional materials; integrating them onto a substrate at the nanoscale is a key factor to develop next-generation devices, such as microarrays of biochips . For example, the anti-p24 IgG protein (molecular) array exhibits great potential for ultrasensitive detection and high-throughput analysis …”