Yazar "Ozsoy C." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot
    (Elsevier, 2015) Demir N.; Oner I.; Varlikli C.; Ozsoy C.; Zafer C.
    Electroluminescence (EL) efficiency from a single emission layer solution processed yellow emitting polymer, i.e. poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,10,3}-thiadiazole)] end-capped with dimethylphenyl (ADS233YE), is firstly enhanced by the optimization of stock polymer concentrations and the coating rates, and then with the addition of copper indium disulfide/zinc sulfide (CIS/ZnS) core/shell quantum dots (QDs). Using these bare core/shell QDs as the active layer in the studied device gave no EL at all. However, yellow EL with the maximum brightness of 56834 cd/m2, maximum current efficiency of 4.7 cd/A and maximum power efficiency of 2.3 lm/W is obtained from the device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ADS233YE:0.4 wt.% CIS/ZnS QD/Ca/Al those of which correspond to approximately 4 and 2 folds of enhancements in the brightness and luminous and power efficiency values, respectively, compared to that of the device without CIS/ZnS. © 2015 Elsevier B.V.
  • Küçük Resim Yok
    Öğe
    Highly efficient MEH-PPV-POSS based PLEDs through optimization of charge transport
    (2012) Saygili G.; Varlikli C.; Zafer C.; Ozsoy C.
    We demonstrated highly efficient devices based on well-known poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] end capped with POSS (MEH-PPV-POSS) polymer by combining of two approaches: (i) inserting of electron transport material (ETM) either between the emissive layer and cathode or into the emissive polymer, and (ii) doping of polymer with quantum dots (QDs). In order to overcome some handicaps, such as interchain interaction and imbalanced charge carrier fluxes, copper indium disulfide (CuInS 2) QDs were incorporated into the polymer matrix, while N-arylbenzimidazoles trimer (TPBi) and 4,7-dipheyl-1,10-phenanthroline (Bphen) were used as ETMs. The best charge carrier balance and color purity were achieved by inserting 0.3 wt% CuInS 2 into the polymer and 40 nm Bphen between the polymer and cathode with a current efficiency of 5.1 cd/A and an external quantum efficiency of 1% which is above the average of literature. © 2012 Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    The synthesis and characterization of 2-(2'-pyridyl)benzimidazole heteroleptic ruthenium complex: Efficient sensitizer for molecular photovoltaics
    (2010) Sahin C.; Ulusoy M.; Zafer C.; Ozsoy C.; Varlikli C.; Dittrich T.; Cetinkaya B.; Icli S.
    The novel ligand 1-(2,4,6-trimethylbenzyl)-2-(2'-pyridyl)benzimidazole and its heteroleptic ruthenium (II) complex were synthesized. The complex was characterized using spectroscopic methods and cyclic voltammetry. Charge-separation was investigated within nanoporous titanium dioxide employing surface photovoltage spectroscopy. The performance of the ruthenium complex as a charge transfer photosensitizer in nanocrystalline, titanium dioxide-based, dye sensitized solar cells was studied under standard AM 1.5 sunlight using an electrolyte consisting of 0.6 M 1-butyl-3-methyl-imidazolium iodide, 0.1 M lithium iodide, 0.05 M iodine and 0.5 M 4-tert-butyl pyridine in 3-methoxy propyonitrile. The novel complex had a photocurrent density of 9.47 mA cm -2 , 600 mV open circuit potential and 0.60 fill factor yielding an efficiency of 3.4%. The photovoltaic performance of the colorant was compared with that of cis-bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato) (2,2'-bipyridyl-4,4'-di-nonyl) ruthenium(II); both compounds exhibited similar efficiency, while the fill factor value was higher for the novel dye. © 2009 Elsevier Ltd. All rights reserved.