Sharbati, Mohammad Taghi
(2016)
GRAPHENE QUANTUM DOT-BASED ORGANIC LOGHT EMITTING DIODES.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Graphene quantum dots (GQDs) have received a great deal of attention due to their unique optical properties, potentially useful for various applications such as display technology, optoelectronics, photovoltaics, sensing, and bioimaging. In this thesis we have investigated GQDs for an emissive layer in all-solution-processed organic light emitting diodes (OLEDs). Our GQD-based OLEDs are designed and fabricated as two different structures: bottom emission configuration on ITO substrate and top emission configuration on p-Si substrate. For both structures, GQDs show multiple emission peaks in blue, green and red regions. This multi-wavelength emission in the visible spectral range suggests presence and involvement of different-sized GQDs. In the case of GQD-OLEDs on silicon substrate, we have applied a SiO2 buffer layer with various thickness (2-150nm) and investigated the effects on carrier injection and confinement. With thin layers (< 10nm) of SiO2 it is found that the oxide layer well serves as a barrier blocking the direct tunneling of holes from the substrate. With thick layers (20-150nm) of SiO2 a band bending occurs enabling the Fowler-Nordheim (FN) tunneling of holes into the p-type transport layer. The FN-tunneling-enabled hole injection is found to allow varying the GQD excitation level (carrier energy and concentration), as demonstrated by the spectral change for different oxide thickness.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Sharbati, Mohammad Taghi | mos44@pitt.edu | | |
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| ETD Committee: |
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| Date: |
15 September 2016 |
| Date Type: |
Publication |
| Defense Date: |
8 April 2016 |
| Approval Date: |
15 September 2016 |
| Submission Date: |
11 August 2016 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
100 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Electrical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
OLED, Organic Light Emitting Diode, GQD, Graphene Quantum Dot, GQD-OLED, Top-Emitting OLED, Bottom-Emitting OLED, Silicon based OLED, GQD Photoluminescence, GQD Electroluminescence, Photoluminescence (PL), Electroluminescence (EL), Red Emitting GQD |
| Date Deposited: |
15 Sep 2016 19:48 |
| Last Modified: |
16 Sep 2016 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/29260 |
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