Search

Now showing items 1-10 of 17

Low-cost, large-scale, ordered ZnO nanopillar arrays for light extraction efficiency enhancement in quantum dot light-emitting diodes

Yang, X.; Dev, K.; Wang, J.; Mutlugün, E.; Dang, C.; Zhao, Y.; Tan, S. T.; Sun, X. W.; Demir, Hilmi Volkan (IEEE, 2014)

We report a QLED with enhanced light outcoupling efficiency by applying a layer of periodic ZnO nanopillar arrays. The resulting QLED reaches the record external quantum efficiency (EQE) of 9.34% in green-emitting QLEDs ...

High-stability, high-efficiency organic monoliths made of oligomer nanoparticles wrapped in organic matrix

Soran-Erdem Z.; Erdem, T.; Gungor K.; Pennakalathil, J.; Tuncel, D.; Demir, Hilmi Volkan (American Chemical Society, 2016)

Oligomer nanoparticles (OL NPs) have been considered unsuitable for solid-state lighting due to their low quantum yields and low temperature stability of their emission. Here, we address these problems by forming highly ...

Coupling and power transfer efficiency enhancement of modular and array of planar coils using in-plane ring-shaped inner ferrites for inductive heating applications

Kilic V.T.; Unal, E.; Demir, Hilmi Volkan (American Institute of Physics Inc., 2017)

We propose and demonstrate a highly effective method of enhancing coupling and power transfer efficiency in inductive heating systems composed of planar coils. The proposed method is based on locating ring-shaped ferrites ...

High-efficiency low-crosstalk dielectric metasurfaces of mid-wave infrared focal plane arrays

Akın, O.; Demir, Hilmi Volkan (American Institute of Physics Inc., 2017)

High-resolution compact-size focal plane arrays (FPAs) suffer the fundamental geometrical tradeoff between the optical resolution (pixel size miniaturization) and the optical crosstalk (spillover of neighboring pixel ...

Graded-host phosphorescent light-emitting diodes with high efficiency and reduced roll-off

Liu, S. W.; Sun, X. W.; Demir, Hilmi Volkan (A I P Publishing LLC, 2012)

We demonstrated graded-host phosphorescent organic light-emitting diodes with high efficiency and reduced efficiency roll-off. The emissive layer of the graded host device consists of both electron and hole transport type ...

A charge inverter for III-nitride light-emitting diodes

Zhang Z.-H.; Zhang, Y.; Bi, W.; Geng, C.; Xu S.; Demir, Hilmi Volkan; Sun, X. W. (American Institute of Physics Inc., 2016)

In this work, we propose a charge inverter that substantially increases the hole injection efficiency for InGaN/GaN light-emitting diodes (LEDs). The charge inverter consists of a metal/electrode, an insulator, and a ...

Comparative study of optically activated nanocomposites with photocatalytic TiO2 and ZnO nanoparticles for massive environmental decontamination

Tek, S.; Mutlugun, E.; Soganci, I. M.; Perkgoz, N. K.; Yucel, D.; Celiker, G.; Demir, Hilmi Volkan (S P I E - International Society for Optical Engineering, 2007)

Nanocomposites that incorporate TiO2 and ZnO nanoparticles separately in three-dimensional solgel matrices through full chemical integration are prepared to perform highly efficient photocatalytic activities for applications ...

Improving hole injection efficiency by manipulating the hole transport mechanism through p-type electron blocking layer engineering

Zhang, Zi-Hui; Ju, Z.; Liu W.; Tan S.T.; Ji Y.; Kyaw, Z.; Zhang X.; Hasanov N.; Sun, X. W.; Demir, Hilmi Volkan (Optical Society of America, 2014)

The p-type AlGaN electron blocking layer (EBL) is widely used in InGaN/GaN light-emitting diodes (LEDs) for electron overflow suppression. However, a typical EBL also reduces the hole injection efficiency, because holes ...

Near-unity emitting copper-doped colloidal semiconductor quantum wells for luminescent solar concentrators

Sharma, M.; Gungor K.; Yeltik A.; Olutas M.; Guzelturk, B.; Kelestemur Y.; Erdem, T.; Delikanli S.; McBride, J. R.; Demir, Hilmi Volkan (Wiley-VCH Verlag, 2017)

Doping of bulk semiconductors has revealed widespread success in optoelectronic applications. In the past few decades, substantial effort has been engaged for doping at the nanoscale. Recently, doped colloidal quantum dots ...

On the triplet distribution and its effect on an improved phosphorescent organic light-emitting diode

Liu, S. W.; Divayana, Y.; Abiyasa, A. P.; Tan S.T.; Demir, Hilmi Volkan; Sun, X. W. (AIP Publishing, 2012-08-28)

We reported phosphorescent organic light-emitting diodes with internal quantum efficiency near 100% with significantly reduced efficiency roll-off. It was found that the use of different hole transporting layer (HTL) affects ...