Stable and efficient colour enrichment powders of nonpolar nanocrystals in LiCl

Erdem, Talha
Sharma, Vijay Kumar
Keleştemur, Yusuf
Adam, Marcus
Gaponik, Nikolai
Demir, Hilmi Volkan
In this work, we propose and develop the inorganic salt encapsulation of semiconductor nanocrystal (NC) dispersion in a nonpolar phase to make a highly stable and highly efficient colour converting powder for colour enrichment in light-emitting diode backlighting. Here the wrapping of the as-synthesized green-emitting CdSe/CdZnSeS/ZnS nanocrystals into a salt matrix without ligand exchange is uniquely enabled by using a LiCl ionic host dissolved in tetrahydrofuran (THF), which simultaneously disperses these nonpolar nanocrystals. We studied the emission stability of the solid films prepared using NCs with and without LiCl encapsulation on blue LEDs driven at high current levels. The encapsulated NC powder in epoxy preserved 95.5% of the initial emission intensity and stabilized at this level while the emission intensity of NCs without salt encapsulation continuously decreased to 34.7% of its initial value after 96 h of operation. In addition, we investigated the effect of ionic salt encapsulation on the quantum efficiency of nonpolar NCs and found the quantum efficiency of the NCs-inLiCl to be 75.1% while that of the NCs in dispersion was 73.0% and that in a film without LiCl encapsulation was 67.9%. We believe that such ionic salt encapsulated powders of nonpolar NCs presented here will find ubiquitous use for colour enrichment in display backlighting.


Novel phenanthrocarbazole containing conjugated polymers as high performance electrochromic materials
Atakan, Gizem; Günbaş, Emrullah Görkem; Department of Chemistry (2016)
For potential application of electrochromic materials in display technologies, materials having additive or subtractive primary colors in their neutral states that switch to a highly tranmissive states are desired since the entire color spectrum can be created using these materials. The RGB color model requires three complementary colors; red, green and blue. Even though the RGB colored polymers in the electrochromic research area were fulfilled over the past decade, towards high quality display application...
Synthesis of benzotriazole bearing donor acceptor type electroactive monomers towards high optical contrast and fast switching electrochromic materials
Balan, Abidin; Toppare, Levent Kamil; Department of Chemistry (2009)
Synthesis of new electroactive monomers are highly desired since these compounds can be utilized as active layers in many device applications such as ECDs, LEDs and solar cells. EDOT (3,4 ethylenedioxythiophene) and thiophene bearing polymers were also proven to be excellent candidates as electrochromic materials. Benzotriazole can be coupled to EDOT and thiophene to yield materials that can be polymerized to give donor acceptor type polymers. These materials are promising candidates as components in fast s...
Formation and characterization of infrared absorbing copper oxide surfaces
Arslan, Burcu; Erdogan, Metehan; Karakaya, İshak (2017-04-30)
Copper oxide formation has been investigated to combine the advantages of producing different size and shapes of coatings that possess good light absorbing properties. An aqueous blackening solution was investigated and optimum composition was found as 2.5 M NaOH and 0.225 M NaClO to form velvet copper oxide films. A two-step oxidation mechanism was proposed for the blackening process by carefully examining the experimental results. Formation of Cu2O was observed until the entire copper surface was covered ...
Efficient light emitting diodes from ternary blends of PPV-based copolymers
Çırpan, Ali; KARASZ, Frank E. (Wiley, 2006-11-05)
Light emitting diodes (LEDs) were prepared using ternary blends of block copolymers emitting in the blue (I and II) and green (III) regime. These blends were studied in terms of their absorbance, photoluminescence (PL), and electroluminescence (EL) spectra. The PL spectra in dilute solution and in the solid state were compared. Förster energy transfer from I and II to III was studied in the solid state. The EL device made using a ternary blend with the ratio (1 : 1 : 1) showed the highest EL quantum efficie...
Surface-enhanced Raman scattering spectroscopy via gold nanostars
Nalbant Esentürk, Emren (Wiley, 2009-01-01)
Anisotropic metallic nanoparticles (NPs) have unique optical properties, which lend them to applications such as surface-enhanced Raman scattering (SERS) spectroscopy. Star-shaped gold (Au) NPs were prepared in aqueous solutions by the seed-mediated growth method and tested for Raman enhancement using 2-mercaptopyridine (2-MPy) and crystal violet (CV) probing molecules. For both molecules, the SERS activity of the nanostars was notably stronger than that of the spherical Au NPs of similar size. The Raman en...
Citation Formats
T. Erdem et al., “Stable and efficient colour enrichment powders of nonpolar nanocrystals in LiCl,” NANOSCALE, vol. 7, no. 42, pp. 17611–17616, 2015, Accessed: 00, 2021. [Online]. Available: