Speaker: Assoc. Prof. Hüsnü Emrah Ünalan, Middle East Technical University

Topic: "Transparent Contacts With Metal Nanowire Networks"

Location: Middle East Technical University, Ankara, Turkey

Abstract: Figure of merit transparency and sheet resistance values of the metal nanowire networks are very close, if not better, than those of commercially available transparent and conducting thin films, such as indium tin oxide (ITO). In addition, nanowire networks carry the prominent advantage of solution processability. In this presentation, I will talk about our efforts on the utilization of silver (Ag) and copper (Cu) nanowire networks as transparent contacts for polymeric light emitting diodes, solar cells and transparent heaters. Following their synthesis and purification, nanowires are deposited onto various substrates in the form of networks through spray coating. Surface roughness and long-term stability of the networks are carefully monitored, where the latter is a particularly important problem for Cu nanowires. Infiltration of a conducting polymer decreased the roughness associated with the networks so that they can be used as anodes in polymeric light emitting diodes. In order to eliminate the shading losses associated with conventional screen-printed finger electrodes in single crystalline silicon solar cells, networks were utilized as top contacts. Through the application of a post-deposition treatment for the formation of the ohmic contacts, a relative enhancement in conversion efficiency of 21% was obtained with respect to the reference cells. When used as transparent heaters, reproducible heating characteristics and uniform temperature distribution was obtained from the networks. The effect of nanowire density on the temperature profile, applied voltage as well as turn on/off characteristics were investigated.

Bio: Emrah Unalan received the BS degree in Metallurgical and Materials Engineering from Middle East Technical University, Turkey in 2002 and the MS and PhD degree in Materials Science and Engineering at Rutgers University, USA in 2004 and 2006, respectively. From 2006 to 2008, he was a Research Associate in Electrical Engineering Division in Engineering Department at University of Cambridge, UK. In 2008, he joined Department of Metallurgical and Materials Engineering, Middle East Technical University, where he is currently an Associate Professor. His research interests include synthesis of nanotubes/nanowires and their utilization in flexible, transparent, stretchable and textile integrated electronics and energy harvesting devices. The aim of his research is not only the utilization of nanomaterials for unforeseen applications through the fabrication of novel devices but also seeking possibilities for new device concepts and form factors. He is a member of Materials Research Society (MRS), American Chemical Society (ACS) and a recipient of the Turkish Academy of Sciences Young Scientist Award in 2009, The Scientific and Technological Research Council of Turkey (TUBITAK) Incentive Award in 2014, Science Academy Young Scientist Award in 2015.

  Date and Time




  • Ankara, Ankara
  • Turkey


Assoc. Prof. Husnu Emrah Unalan of Middle East Technical University


Transparent Contacts With Metal Nanowire Networks



Address:Ankara, Turkey