| LDR | | 00000nam u2200205 4500 |
| 001 | | 000000433624 |
| 005 | | 20200225151710 |
| 008 | | 200131s2019 ||||||||||||||||| ||eng d |
| 020 | |
▼a 9781687955012 |
| 035 | |
▼a (MiAaPQ)AAI22618825 |
| 040 | |
▼a MiAaPQ
▼c MiAaPQ
▼d 247004 |
| 082 | 0 |
▼a 620.5 |
| 100 | 1 |
▼a Esopi, Monica R. |
| 245 | 10 |
▼a Spectral Photoresponse Tuning and Enhancement in Organic Ultraviolet Photodetectors through Active Layer Optimization and Plasmonic Nanostructures. |
| 260 | |
▼a [S.l.]:
▼b University of Washington.,
▼c 2019. |
| 260 | 1 |
▼a Ann Arbor:
▼b ProQuest Dissertations & Theses,
▼c 2019. |
| 300 | |
▼a 203 p. |
| 500 | |
▼a Source: Dissertations Abstracts International, Volume: 81-04, Section: B. |
| 500 | |
▼a Advisor: Yu, Qiuming. |
| 502 | 1 |
▼a Thesis (Ph.D.)--University of Washington, 2019. |
| 506 | |
▼a This item must not be sold to any third party vendors. |
| 506 | |
▼a This item must not be added to any third party search indexes. |
| 520 | |
▼a Ultraviolet photodetectors are important in a wide variety of applications including scientific measurement, environmental monitoring, imaging, and flame and missile detection. Organic active materials offer a low-cost, flexible, solution-processable alternative to inorganic materials. Strong, sensitive photoresponse with wavelength selectivity and tunability is highly desired, and can be achieved through material selection, active layer manipulation, and plasmonic nanostructure incorporation. In this work, 3D-finite-difference time domain (FDTD) electromagnetic simulations, transfer-matrix method (TMM) optical simulations, and experimental approaches were integrated to understand the relationship between physical parameters, underlying device physics, and photoresponse mechanisms to develop organic UV photodetectors with strong, sensitive, tunable photoresponse.Conventional organic photodiodes with active layers composed of blends of wide bandgap polymers and fullerene derivatives or ZnO nanoparticles were used to achieve strong and narrowband UV photoresponse via the mechanisms of photomultiplication and charge collection narrowing (CCN). By reducing the content of [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) in a polymer poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) active layer, isolated PC71BM clusters were formed and trapped electrons near the device cathode, resulting in band bending and hole injection, thus enabling multiple holes to be collected per incident photon and achieving photomultiplication. A peak EQE of 5600%, under 360 nm illumination and -40 V bias, was achieved by devices utilizing a 100:4 w:w blend of F8T2:PC71BM. Devices with active layers composed of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) and ZnO nanoparticles had photoresponse that could be tuned from broad and photomultiplicative to spectrally narrowband by using thin and thick active layers, respectively, via the CNN mechanism. A single EQE peak at 424 nm with a full-width at half-maximum of just 12 nm was demonstrated when a thick active layer was used. UV photoresponse was further tuned and enhanced by incorporating Al plasmonic nanostructure arrays, either as a transparent bottom electrode or a top electrode in conventional UV photodetectors. Al nanohole arrays (Al-NHAs) were incorporated into UV photodetectors as transparent electrodes and the resulting photoresponse spectra varied from having two peaks under reverse bias to a distinct, single peak under forward bias. This novel bias-dependent photoresponse switching was enabled by plasmonic enhancements to the electric field in the active layer, which acted as an additional forward bias in Al-NHA-based devices. Plasmonic Al nanostructures were also incorporated into the top device electrode in the form of a nanohemisphere array (NHSA) to engage the mechanisms of light scattering and electric field enhancement, which improve the strength and speed of photoresponse. This work sheds light on the improvement of UV photodetection through active layer optimization and plasmonic nanostructure incorporation, and opens up avenues to develop sensitive, spectrally selective photodetectors to meet the expanding photodetection needs of modern technology. |
| 590 | |
▼a School code: 0250. |
| 650 | 4 |
▼a Chemical engineering. |
| 650 | 4 |
▼a Optics. |
| 650 | 4 |
▼a Nanotechnology. |
| 690 | |
▼a 0542 |
| 690 | |
▼a 0752 |
| 690 | |
▼a 0652 |
| 710 | 20 |
▼a University of Washington.
▼b Chemical Engineering. |
| 773 | 0 |
▼t Dissertations Abstracts International
▼g 81-04B. |
| 773 | |
▼t Dissertation Abstract International |
| 790 | |
▼a 0250 |
| 791 | |
▼a Ph.D. |
| 792 | |
▼a 2019 |
| 793 | |
▼a English |
| 856 | 40 |
▼u http://www.riss.kr/pdu/ddodLink.do?id=T15493574
▼n KERIS
▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
| 980 | |
▼a 202002
▼f 2020 |
| 990 | |
▼a ***1008102 |
| 991 | |
▼a E-BOOK |