Electrochromic Switch Devices Mixing Small- and Large-Sized Upconverting Nanocrystals
authors Martinez, ED; Brites, CDS; Carlos, LD; Garcia-Flores, AF; Urbano, RR; Rettori, C
nationality International
journal ADVANCED FUNCTIONAL MATERIALS
author keywords electrothermal control; high thermal sensitivity; optoelectronic devices; silver nanowires; upconversion nanoparticles
keywords UP-CONVERSION LUMINESCENCE; TEMPERATURE-DEPENDENCE; NANOWIRE NETWORKS; NANOPARTICLES; SHELL; CORE; ER3+; PHASE; STATE
abstract The hasty progress in smart, portable, flexible, and transparent integrated electronics and optoelectronics is currently one of the driving forces in nanoscience and nanotechnology. A promising approach is the combination of transparent conducting electrode materials (e.g., silver nanowires, AgNWs) and upconverting nanoparticles (UCNPs). Here, electrochromic devices based on transparent nanocomposite films of poly(methyl methacrylate) and AgNWs covered by UCNPs of different sizes and compositions are developed. By combining the electrical control of the heat dissipation in AgNW networks with size-dependent thermal properties of UCNPs, tunable electrochromic transparent devices covering a broad range of the chromatic diagrams are fabricated. As illustrative examples, devices mixing large-sized (>70 nm) beta-NaYF4:Yb,Ln and small-sized (<15 nm) NaGdF4:Yb,Ln@NaYF4 core@shell UCNPs (Ln = Tm, Er, Ce/Ho) are presented, permitting to monitor the temperature-dependent emission of the particles by the intensity ratio of the Er3+ 2H11/2 and S-4(3/2) -> I-4(15/2) emission lines, while externally controlling the current flow in the AgNW network. Moreover, by defining a new thermometric parameter involving the intensity ratio of transitions of large- and small-sized UCNPs, a relative thermal sensitivity of 5.88% K-1 (at 339 K) is obtained, a sixfold improvement over the values reported so far.
publisher WILEY-V C H VERLAG GMBH
issn 1616-301X
year published 2019
volume 29
issue 8
digital object identifier (doi) 10.1002/adfm.201807758
web of science category Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter
subject category Chemistry; Science & Technology - Other Topics; Materials Science; Physics
unique article identifier WOS:000459826500020

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