Davood Kalhor

Assistant Professor in Photonics

Selected Publications

Kalhor, D., Mohajerani, E., Hashemi Pour, O. The effect of Indium metal nanoparticles on the electronic properties of organic light emitting diodes (OLEDs) (2015) 167, art. no. 13461, pp. 376-380.

DOI: 10.1016/j.jlumin.2015.07.011

Abstract In this paper the effect of Indium nanoparticles (NPs) on the electronic properties of organic light emitting diodes (OLEDs) is experimentally investigated. The metal NPs which are added to the hole transfer layer can be considered as a blocker layer for injected electrons. By optimizing hole and electron ratio, current density and voltage can be decreased. In order to study this effect, among various fabricated devices, a specific structure, namely ITO/PEDOT:PSS (50 nm)/TPD (45 nm)/NPs (x nm)/Alq3 (50 nm)/Ag (80 nm) has been used. Also, the experiment is investigated for Au and Cu as different cathode the results of structures are compared with Ag cathode. A manually controllable shutter was used for vacuum deposition process to prepare the same structures and to avoid any disturbing effects. It is observed that specific Indium NPs reduce current density and turn on voltage of the device. © 2015 Elsevier B.V.

AUTHOR KEYWORDS: Indium; Metal cathode; Nanoparticles; NPs; OLED; Organic light-emitting device
INDEX KEYWORDS: Cathodes; Current density; Electrodes; Electronic properties; Indium; Light emitting diodes; Metal nanoparticles; Nanoparticles, Indium nanoparticles; Injected electrons; Metal cathodes; NPs; OLED; Organic light emitting diodes(OLEDs); Organic light-emitting devices; Vacuum deposition process, Organic light emitting diodes (OLED)

Kalhor, D., Zahiri, R., Ketabi, S.A., Ebrahimzad, A. The effect of Ag intermediate layer on crystalline, optical and electrical properties of nano-structured thin film (2010) 84 (5), pp. 539-546.

ITO thin films and ITO/Ag/ITO multilayered films were prepared on glass substrate by reactive thermal evaporation technique without intentionally heating the substrate. After deposition the films were annealed in air at three different temperatures (300°C, 420°C and 540°C). The thickness of each layer in the ITO/Ag/ITO films was kept constant at 50 nm/10 nm/40 nm. The opto-electrical and structural properties of ITO/Ag/ITO multilayered films were compared with conventional ITO single-layer films. Although both films had identical thickness, 100 nm, the ITO/Ag/ITO films showed a lower resistivity. XRD spectra showed that Ag intermediate layer had a small effect on crystalline properties of ITO/Ag/ITO films. © 2010 IACS.

AUTHOR KEYWORDS: Annealing; Indium-tin-oxide; Multilayered films; Thermal evaporation

Mohammadi Gheidari, A., Hadad Dabaghi, H., Kalhor, D., Iraj, M., Kazemzad, M., Behafarid, F. Post annealing effects on the properties of sputtered nano-crystallite indium tin oxide thin films on flexible polyimide substrate (2008) 5 (10), pp. 3338-3343.

DOI: 10.1002/pssc.200778928

Indium tin oxide (ITO) thin films were deposited onto flexible polyimide substrates using RF sputtering system at room temperature. The deposited films were then heat treated at different temperatures in air and vacuum atmospheres. The structural variations and as consequence the electro-optical characteristic variations of the films were systematically investigated as a function of post annealing temperature and atmosphere. The structure of the films was studied by means of XRD and SEM techniques and the electro-optical characteristics were measured by four point probe and spectrophotometer, respectively. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.

INDEX KEYWORDS: Deposited films; Electro-optical characteristics; Flexible polyimide substrate; Four point probe; Indium tin oxide thin films; Post-annealing effect; Post-annealing temperature; RF sputtering system; Room temperature; SEM; Structural variations; XRD, Annealing; Indium; ITO glass; Optical materials; Oxide films; Photolithography; Polyimides; Semiconductor lasers; Semiconductor switches; Substrates; Technical presentations; Thin films; Tin; Titanium compounds; X ray diffraction, Atmospheric temperature