Type
Text
Type
Thesis
Advisor
Xin, Huolin | Raghothamachar, Balaji. | Gersappe, Dilip
Date
2015-12-01
Keywords
Engineering | Electron Diffraction, Inelastic Scattering, Polymers, Radiation Damage, TEM
Department
Department of Materials Science and Engineering.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76351
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
In general polymeric materials are sensitive to the electron beam in the transmission electron microscopes (TEM). Radiolysis or ionization is the primary mechanism by which these materials are damaged under electron irradiation. Moreover, the image resolution of these materials in a TEM is determined by radiation damage. In the following work we determine the radiation sensitivity and damage mechanism for a single crystal organic material 3,6-bis (5-(4-n-butylphenyl) thiophene-2-yl)-2,5-bis (2-ethylhexyl) pyrrolo[3,4-c]pyrrole-1,4-dione (DPP-PR) majorly used for organic photovoltaic (OPV) applications as a donor material. We provide a complete experimental and analysis procedure for radiation damage study by utilizing electron diffraction patterns. First at 120KeV, we learn that the critical dose value doesn’t change significantly with the dose rate. The critical dose is independent of the dose rate. Second, we experimentally determine critical dose (D_e) values 3 (e^-/〖A^o〗^2 ) and 6 (e^-/〖A^o〗^2 ) at electron energies of 120KeV and 200KeV respectively. We find the increase in the value of the critical dose, which indicates an increase in the resistance of the material to radiation damage at higher electron energies. The ionization mechanism causes the breakage of the bonds of the DPP polymer leading to the loss of crystalline structure. We also conducted the experiment at low temperature of -175℃ at 120KeV. And the determined critical dose value is 8(e^-/〖A^o〗^2 ). Hence we confirm that reducing the temperature is effective to reduce radiation damage for the polymers. | In general polymeric materials are sensitive to the electron beam in the transmission electron microscopes (TEM). Radiolysis or ionization is the primary mechanism by which these materials are damaged under electron irradiation. Moreover, the image resolution of these materials in a TEM is determined by radiation damage. In the following work we determine the radiation sensitivity and damage mechanism for a single crystal organic material 3,6-bis (5-(4-n-butylphenyl) thiophene-2-yl)-2,5-bis (2-ethylhexyl) pyrrolo[3,4-c]pyrrole-1,4-dione (DPP-PR) majorly used for organic photovoltaic (OPV) applications as a donor material. We provide a complete experimental and analysis procedure for radiation damage study by utilizing electron diffraction patterns. First at 120KeV, we learn that the critical dose value doesn’t change significantly with the dose rate. The critical dose is independent of the dose rate. Second, we experimentally determine critical dose (D_e) values 3 (e^-/〖A^o〗^2 ) and 6 (e^-/〖A^o〗^2 ) at electron energies of 120KeV and 200KeV respectively. We find the increase in the value of the critical dose, which indicates an increase in the resistance of the material to radiation damage at higher electron energies. The ionization mechanism causes the breakage of the bonds of the DPP polymer leading to the loss of crystalline structure. We also conducted the experiment at low temperature of -175℃ at 120KeV. And the determined critical dose value is 8(e^-/〖A^o〗^2 ). Hence we confirm that reducing the temperature is effective to reduce radiation damage for the polymers. | 68 pages
Recommended Citation
Vishnubhotla, sai bharadwaj, "Radiation Damage Study Of A DPP Polymer Using Transmission Electron Microscope" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2275.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2275