Browsing by Author "Arslan, Aysenur"

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Simple, Sustainable Fabrication of Fully Solution-Processed, Transparent, Metal-Semiconductor Photodetectors Using a Surgical Blade as an Alternative to Conventional Tools
(SPIE - The International Society for Optics and Photonics, 2022) Savas, Muzeyyen; Yazici, Ahmet Faruk; Arslan, Aysenur; Mutlugun, Evren; Erdem, Talha
Fabrication of optoelectronic devices relies on the expensive, energy-consuming conventional tools such as chemical vapor deposition, lithography, and metal evaporation. Furthermore, the films used in these devices are usually deposited at elevated temperatures and under vacuum that impose further restrictions to the device fabrication. Developing an alternative technology would contribute to the efforts on achieving a more sustainable optoelectronics technology. Keeping this focus in our focus, here we present a simple technique to fabricate visible photodetectors. These fully solution-processed and transparent metal-semiconductor-metal photodetectors employ silver nanowires (Ag NW) as the transparent electrodes replacing the indium-tin oxide (ITO) commonly used in optoelectronic devices. By repeatedly spin coating Ag NWs on a glass substrate followed by the coating of ZnO nanoparticles, we obtained a highly conductive transparent electrode reaching a sheet resistance of 95 Omega/square as measured by the four-probe method. Optical spectroscopy revealed that the transmittance of the Ag NW-ZnO films was 84% at 450 nm while transmittance of the ITO films was 90% at same wavelength. Following the formation of the conductive film, we scratched it using a heated surgical blade to open a gap. The scanning electron microscope images indicate that a gap of similar to 30 mm is opened forming an insulating line. As the active layer, we drop-casted red-emitting CdSe/ZnS core-shell quantum dots (QDs) on to this gap to form a metal-semiconductor-metal photodetector. These visible QD- based photodetectors exhibited responsivities and detectivities up to 8.5 mA/W and 0.95x10(9) Jones, respectively. These proof-of-concept photodetectors show that the environmentally friendly, low- cost, and energy-saving technique presented here can be an alternative to conventional, more expensive, and energy-hungry techniques while fabricating light-harvesting devices.
Citation - WoS: 2
Citation - Scopus: 1
Toward Sustainable Optoelectronics: Solution-Processed Quantum Dot Photodetector Fabrication Using a Surgical Blade
(SPIE - Society of Photo-Optical Instrumentation Engineers, 2023) Savas, Muzeyyen; Yazici, Ahmet Faruk; Arslan, Aysenur; Mutluguen, Evren; Erdem, Talha
Fabrication of optoelectronic devices relies on expensive, energy-consuming conventional tools including chemical vapor deposition, lithography, and metal evaporation. Furthermore, the films used in these devices are usually deposited at elevated temperatures (> 300 degrees C) and under high vacuum, which necessitate further restrictions on the device fabrication. Developing an alternative technology would contribute to the efforts on achieving a sustainable optoelectronics technology. Keeping this in our focus, here we present a simple technique to fabricate visible photodetectors (PDs). These fully solution-processed and transparent metal-semiconductor-metal (MSM) PDs employ silver nanowires (Ag NW) as the transparent electrodes replacing the indium-tin-oxide (ITO) commonly used in optoelectronic devices. By repeatedly spin coating Ag NWs on a glass substrate followed by the coating of zinc oxide nanoparticles, we obtained a highly conductive transparent electrode reaching a sheet resistance of 95 omega/? as measured by the four-probe method. Optical spectroscopy revealed that the transmittance of the Ag NW-ZnO films was 84% at 450 nm while the transmittance of the ITO films was 90% at the same wavelength. Following the formation of the conductive film, we scratched it using a heated surgical blade to open a gap. The scanning electron microscope images indicate that a gap of similar to 30 mu m is opened forming an insulating line. As the active layer, we drop-casted red-emitting CdSe/ZnS core-shell quantum dots (QDs) onto this gap to form a MSM PD. These visible QD-based PDs exhibited responsivities and detectivities up to 8.5 mA/W and 0.95 x 109 Jones, respectively at a bias voltage of 5 V and wavelength of 650 nm. These proof-of-concept PDs show that the environmentally friendly, low-cost, and energy-saving technique presented here can be an alternative to conventional, high-cost, and energy-hungry techniques while fabricating photoconductive devices.
Citation - WoS: 11
Citation - Scopus: 14
Nanowire-Shaped MoS2@MoO3 Nanocomposites as a Hole Injection Layer for Quantum Dot Light-Emitting Diodes
(Amer Chemical Soc, 2022) Bastami, Nasim; Soheyli, Ehsan; Arslan, Aysenur; Sahraei, Reza; Yazici, Ahmet Faruk; Mutlugun, Evren
Molybdenum disulfides and molybdenum trioxides are structures that possess the potential to work as efficient charge transport layers in optoelectronic devices. In the present study, as opposed to the existing Mo-based nanostructures in flake, sheet, or spherical forms, an extremely simple and low-cost hydrothermal method is used to prepare nanowires (NWs) of MoS2@MoO3 (MSO) composites. The synthesis method includes several advantages including easy handling and processing of inexpensive precursors to reach stable MSO NWs without the need for an oxygen-free medium, which would facilitate the possibility of mass production of these nanostructures. The structural analysis confirmed the formation of MSO nanocomposites with different Mo valence states, as well as NWs of average length and diameter of 70 nm and 5 nm, respectively. In order to demonstrate their potential for optoelectronic applications, MSO NWs were blended into hole injection layers (HILs) in quantum dot-based light emitting diodes (QLEDs). Electroluminescence measurements show a substantial enhancement in both luminance (from 44,330 to 68,630 cd.m-2) and external quantum efficiency (from 1.6 to 2.3%), based on the increase in the ratio of MSO NWs from 3 to 10%. Interestingly, the addition of 10% volume of MSO NWs resulted in a remarkably smoother HIL with improved current efficiency and stability in green-emitting QLEDs. The simplicity and cost-effective features of the synthesis method along with outstanding favorable morphology demonstrated their ability to enhance the QLED performance and mark them as promising agents for optoelectronics.