Journal
IEEE TRANSACTIONS ON NANOTECHNOLOGY
Volume 14, Issue 5, Pages 911-917Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TNANO.2015.2461025
Keywords
Light emitting diode; quantum dot; NiO; ZnO:Ga; photo luminescence
Categories
Funding
- Research Office at the University of Tabriz, Iran
Ask authors/readers for more resources
In this research paper, fabrication of novel CdSe\ZnS QD-LEDs with solution processing method is presented, and the impact of trap energy levels in the electron and hole transport levels on these QD-LEDs brightness is investigated. Two types of QD-LEDs are fabricated with ITO as the transparent anode electrode, NiO nanoparticles as the hole transport layer (HTL), CdSe\ZnS QDs as the luminescent layer, ZnO:Ga as the electron transport layer (ETL), and Al as the cathode electrode. The NiO nanoparticles are synthesized by the sol-gel or alternatively the electrochemical method. Formation of different trap levels is observed in the crystal structures of the NiO nanoparticles synthesized by each of these methods. Considering the electrochemically prepared NiO nanoparticles, it is found that the density of trap levels is higher in the crystal structure of the NiO nanoparticles synthesized by sol-gel method, and the device fabricated by the latter material shows higher performance. Calculation of the electronic structure of ZnO:Ga by DFT methods (GGA-PBE) indicates that doping of Ga in the structure of crystalline ZnO creates new energy levels in conduction band and intermediate bands at the bandgap of ZnO host. It facilitates electron injection from Al cathode to the ZnO:Ga ETL layer and from this layer to the QD-luminescent layer. The fabricated devices show turn-on lower voltages than 5 V in which a peak brightness of 500 and 340 cd.m(-2) is measured for the LEDs fabricated with sol-gel and electrochemically synthesized NiO nanoparticles, respectively.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available