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Öğe Charge transfer through amino groups-small molecules interface improving the performance of electroluminescent devices(Elsevier Science Bv, 2016) Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Kus, Mahmut; Okur, Salih; Demic, Serafettin; Demirak, Kadir; Kurt, Mustafa; Icli, SiddikA carboxylic group functioned charge transporting was synthesized and self-assembled on an indium tin oxide (ITO) anode. A typical electroluminescent device [modified ITO/TPD (50 nm)/Alq(3) (60 nm)/LiF (2 nm)/(120 nm)] was fabricated to investigate the effect of the amino groups-small molecules interface on the characteristics of the device. The increase in the surface work function of ITO is expected to facilitate the hole injection from the ITO anode to the Hole Transport Layer (HTL) in electroluminescence. The modified electroluminescent device could endure a higher current and showed a much higher luminance than the nonmodified one. For the produced electroluminescent devices, the I-V characteristics, optical characterization and quantum yields were performed. The external quantum efficiency of the modified electroluminescent device is improved as the result of the presence of the amino groups-small molecules interface. (C) 2016 Elsevier B.V. All rights reserved.Öğe Effect of TiO2 modification with amino-based self-assembled monolayer on inverted organic solar cell(Elsevier Science Bv, 2017) Tozlu, Cem; Mutlu, Adem; Can, Mustafa; Havare, Ali Kemal; Demic, Serafettin; Icli, SiddikThe effects of surface modification of titanium dioxide (TiO2) on the performance of inverted type organic solar cells (i-OSCs) was investigated in this study. A series of benzoic acid derivatized self-assembled monolayer (SAM) molecules of 4'-[(hexyloxy) phenyl] amino-3,5-biphenyl dicarboxylic acid (CT17) and 4'-[1-naphthyl (phenyl) amino] biphenyl-4-carboxylic acid (CT19) were utilized to modify the interface between TiO2 buffer layer and poly-3 hexylthiophene (P3HT):[ 6,6]-phenyl C-61 butyric acid methyl ester (PC61BM) active layer having the device structure of ITO/TiO2/SAM/P3HT:PC61BM/MoO3/Ag. The work function and surface wetting properties of TiO2 buffer layer served as electron transporting layer between ITO and PC61BM active layer were tuned by SAM method. The solar cell of the SAM modified devices exhibited better performance. The power conversion efficiency (PCE) of i-OSCs devices with bare TiO2 electrodes enhanced from 2.00% to 2.21% and 2.43% with CT17 and CT19 treated TiO2 electrodes, respectively. The open circuit voltage (V-oc) of the SAM treated TiO2 devices reached to 0.60 V and 0.61 V, respectively, while the V-oc of untreated TiO2 was 0.57 V. The water contact angle of i-OSCs with CT17 and CT19 SAMs was also higher than the value of the unmodified TiO2 electrode. These results show that inserting a monolayer at the interface between organic and inorganic layers is an useful alternative method to improve the performance of i-OSCs. (C) 2017 Elsevier B.V. All rights reserved.Öğe Electrical properties of SAM-modified ITO surface using aromatic small molecules with double bond carboxylic acid groups for OLED applications(Elsevier Science Bv, 2014) Can, Mustafa; Havare, Ali Kemal; Aydin, Hasan; Yagmurcukardes, Nesli; Demic, Serafettin; Icli, Siddik; Okur, Salih5-[(3-Methylphenyl)(phenyl)amino]isophthalic acid (5-MePIFA) and 5-(diphenyl)amino]Isophthalic acid (5-DPIFA) organic molecules were synthesized to form self-assembled monolayer on indium tin oxide (ITO) anode to enhance hole transport from ITO to organic hole transport layers such as TPD. The modified surface was characterized by scanning tunneling microscopy (STM). The change in the surface potential was measured by Kelvin probe force microscopy (KPFM). Our Kelvin probe force microscopy (KPFM) measurements showed that the surface potentials increased more than 100 mV with reference to bare indium tin-oxide. The results show that the threshold voltage on OLEDs with modified ITO is lowered significantly compared to OLEDs with unmodified ITO. The hole mobility of TPD has been estimated using space-charge-limited current measurements (SCLC). (C) 2014 Elsevier B.V. All rights reserved.Öğe ITO yüzeyinin SAM tekniği ile modifikasyonu:(Ege Üniversitesi, 2014) Havare, Ali Kemal; Bilgili, Hakan; Can, Mustafa; Demiç, Şerafettin[Abstract Not Available]Öğe Kendiliğinden organize tek katman tekniği (KOT) kullanılarak organik led (OLED) veriminin artırılması ve karekterizasyonu(Ege Üniversitesi, 2011) Havare, Ali Kemal; Demiç, ŞerafettinBu doktora tezinde Kendiliğinden Organize Tekkatman (KOT) tekniği kullanılarak organik LED (OLED) veriminin artırılması ve karekterizasyonu üzerine yoğunlaşılmıştır. OLED’in organik/anorganik arayüzeyindeki zayıf bağlanmanın üstesinden gelebilmek için KOT kullanılarak OLED aygıtının performansı ve kararlılığı artırılmıştır. KOT, hidrofobik özelliğe sahip h+ iletim materyali ile hidrofilik indiyum kalay oksit (ITO) arasında uyumlu bir arayüzey oluşmak için kullanılmıştır. Yeni nesil KOT molekülleri olarak 4'-iodobifenil-4-il) trihidroksisilan (THIBSi), dibenzo[a,c]fenazin-11-karboksilik asit (PBA), 4-(9H-karbazol-9-il)benzoik asit (MZ39), 4-(2,5-di-2-tiyenil-1H-pirol-1-il)benzoik asit (MZ25), 5-[(3-metilfenil)(fenil)amino]izoftalik asit (MePIFA), 5-(difenil)amino]izoftalik asit (DPIFA) bileşikleri ITO üzerine kaplanmıştır. ITO yüzeyi atomik kuvvet mikroskobu, kelvin probe mikroskobu, taramalı tünelleme mikroskobu ve X-ışınları fotoelektron mikroskobu ile karakterize edilmiştir. Modifiye edilmiş ve yalın ITO kaplı cam altlık kullanılarak üretilmiş olan ITO/KOT/HTL/Al ve ITO/HTL/Al konfigürasyonuna sahip Schottky diyotları optimize edilmiş ve yük mobiliteleri karşılaştırılmıştır. Bunun yanı sıra aromatik KOT molekülerinin, lüminesans ve kuantum verimi üzerindeki etkisini görebilmek için OLED’in elektriksel ve optiksel karekterizasyonu yapılmıştır.Öğe Modification of ITO surface using aromatic small molecules with carboxylic acid groups for OLED applications(Elsevier Science Sa, 2011) Havare, Ali Kemal; Can, Mustafa; Demic, Serafettin; Okur, Salih; Kus, Mahmut; Aydin, Hasan; Yagmurcukardes, Nesli; Tari, Suleyman4-[(3-Methylphenyl)(phenyl)amino]benzoic acid (MPPBA) was synthesized in order to facilitate the hole-injection in Organic Light Emitting Diodes (OLED). MPPBA was applied to form self-assembled monolayer (SAM) on indium tin oxide (ITO) anode to align energy-level at the interface between organic semiconductor material (TPD) and inorganic anode (ITO) in OLED devices. The modified surface was characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). KPFM was used to measure the surface potential and work function between the tip and the ITO surface modified by SAM technique using MPPBA. The OLED devices (ITO/MPPBA/TPD/Alq(3)/Al) fabricated with SAM-modified ITO substrates showed lower turn-on voltages and enhanced diode current compare to the OLED devices fabricated with bare ITO substrates. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.Öğe The performance of OLEDs based on sorbitol doped PEDOT:PSS(Elsevier Science Sa, 2012) Havare, Ali Kemal; Can, Mustafa; Demic, Serafettin; Kus, Mahmut; Icli, SiddikWe report the performance of OLED devices with a configuration of FTO/sorbitol-PEDOT:PSS (60 nm)/TPD (50 nm)/Alq(3) (40 nm)/Al (120 nm) and FrO/plain-PEDOT:PSS (60 nm)/TPD (50 nm)/Alq(3) (40 nm)/Al (120 nm) prepared from poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) undoped (plain-PEDOT:PSS) and doped by a constant concentration 5% of sorbitol, respectively. The OLED devices were tested in terms of electrical and optical characteristics in order to investigate the effect of sorbitol doping and thermal annealing on PEDOT:PSS thin film on FTO. The device fabricated from sorbitol-PEDOT:PSS with thermal annealing showed the maximum luminance of 130 (cd m(-2)). The devices with sorbitol doping showed a lowering of the operating voltage from 6.5 down to 3 V. A constant luminous efficiency higher than 1.8 cd A(-1) was obtained in the range of current of 4-7 (mA/cm(2)) with doped sorbitol. Published by Elsevier B.V.
