Color science and technology of novel nanophosphors for high-efficiency high-quality LEDs

Simple item page
buir.advisorDemir, Hilmi Volkan
dc.contributor.authorErdem, Talha
dc.date.accessioned2016-01-08T18:23:53Z
dc.date.available2016-01-08T18:23:53Z
dc.date.issued2011
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.descriptionAnkara : The Department of Electrical and Electronics and the Graduate School of Engineering and Sciences of Bilkent University, 2011.en_US
dc.descriptionThesis (Master's) -- Bilkent University, 2011.en_US
dc.descriptionIncludes bibliographical references leaves 118-129.en_US
dc.description.abstractToday almost one-fifth of the world‟s electrical energy is consumed for artificial lighting. To revolutionize general lighting to reduce its energy consumption, high-efficiency, high-quality light-emitting diodes (LEDs) are necessary. However, to achieve the targeted energy efficiency, present technologies have important drawbacks. For example, phosphor-based LEDs suffer from the emission tail of red phosphors towards longer wavelengths. This deep-red emission decreases substantially the luminous efficiency of optical radiation. Additionally, the emission spectrum of phosphor powders cannot be controlled properly for high-quality lighting, as this requires careful spectral tuning. At this point, new nanophosphors made of colloidal quantum dots and crosslinkable conjugated polymer nanoparticles have risen among the most promising alternative color convertors because they allow for an excellent capability of spectral tuning. In this thesis, we propose and present high-efficiency, highquality white LEDs using quantum dot nanophosphors that that exhibit luminous efficacy of optical radiation ≥380 lm/Wopt, color rendering index ≥90 and correlated color temperature ≤4000 K. We find that Stoke‟s shift causes a fundamental loss >15%, which limits the maximum feasible luminous efficiency to 326.6 lm/Welect. Considering a state-of-the-art blue LED (with 81.3% photon conversion efficiency), this corresponds to 265.5 lm/Welect. To achieve 100 and 200 lm/Welect, the layered quantum dot films are required to have respective quantum efficiencies of 39 and 79%. In addition, we report our numerical modeling and experimental demonstrations of the quantum dot integrated LEDs for the different vision regimes of human eye. Finally, we present LEDs based on the color tuning capability of conjugated polymer nanoparticles for the first time. Considering the outcomes of this thesis, we believe that our research efforts will help the development and industrialization of white light emitting diodes using nanophosphor components.en_US
dc.description.degreeM.S.en_US
dc.description.statementofresponsibilityErdem, Talhaen_US
dc.format.extentxv, 129 leaves, illustrations, graphsen_US
dc.identifier.urihttp://hdl.handle.net/11693/15739
dc.language.isoEnglishen_US
dc.publisherBilkent Universityen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectWhite light emitting diodes (white LED)en_US
dc.subjectColor scienceen_US
dc.subjectPhotometryen_US
dc.subjectLuminous efficacyen_US
dc.subjectColor renderingen_US
dc.subjectColor temperatureen_US
dc.subjectColor tuningen_US
dc.subjectSpectral tuningen_US
dc.subject.lccTK7871.89.L53 E73 2011en_US
dc.subject.lcshLight emitting diodes.en_US
dc.subject.lcshNanocrystals.en_US
dc.subject.lcshColor.en_US
dc.titleColor science and technology of novel nanophosphors for high-efficiency high-quality LEDsen_US
dc.typeThesisen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
0006450.pdf
Size:
2.67 MB
Format:
Adobe Portable Document Format
Download
Collections
Dept. of Electrical and Electronics Engineering - Master's degree