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20150429_PhD Thesis_Bhandari KP.pdf (43.65 MB)

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Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics

Bhandari, Khagendra P
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430327894

Abstract Details

2015, Doctor of Philosophy, University of Toledo, Physics.
Solar energy is Earth’s primary source of renewable energy and photovoltaic solar cells enable the direct conversion of sunlight into electricity. Crystalline silicon solar cells and modules have dominated photovoltaic technology from the beginning and they now constitute more than 90% of the PV market. Thin film (CdTe and CIGS) solar cells and modules come in second position in market share. Some organic, dye-sensitized and perovskite solar cells are emerging in the market but are not yet in full commercial scale. Solar cells made from colloidal nanocrystalline materials may eventually provide both low cost and high efficiency because of their promising properties such as high absorption coefficient, size tunable band gap, and quantum confinement effect. It is also expected that the greenhouse gas emission and energy payback time from nanocrystalline solar PV systems will also be least compared to all other types of PV systems mainly due to the least embodied energy throughout their life time. The two well-known junction architectures for the fabrication of quantum dot based photovoltaic devices are the Schottky junction and heterojunction. In Schottky junction cells, a heteropartner semiconducting material is not required. A low work function metal is used as the back contact, a transparent conducting layer is used as the front contact, and the layer of electronically-coupled quantum dots is placed between these two materials. Schottky junction solar cells explain the usefulness of nanocrystalline materials for high efficiency heterojunction solar cells. For heterojunction devices, n-type semiconducting materials such as ZnO , CdS or TiO2 have been used as suitable heteropartners. Here, PbS quantum dot solar cells were fabricated using ZnO and CdS semiconductor films as window layers. Both of the heteropartners are sputter-deposited onto TCO coated glass substrates; ZnO was deposited with the substrate held at room temperature and for CdS the substrate was at 250 C. Within this work, CdS was demonstrated for the first time as the heteropartner for a quantum dot absorber layer. Iron pyrite nanocrystal (NC) could not be used as an absorber layer in thin film solar cells because the material’s very high free hole density rendered it nearly metallic in nature. However, the author discovered and demonstrated that an iron pyrite nanocrystal film functions well as a back contact buffer layer for CdTe solar cells. Performance of CdTe devices when using FeS2/Au as back contact approaches that of a laboratory standard Cu/Au back contact.
Randy Ellingson (Advisor)
Victor Karpov (Committee Member)
Michael Heben (Committee Member)
Rupali Chandar (Committee Member)
Terry Bigioni (Committee Member)
392 p.
Energy; Engineering; Materials Science; Nanoscience; Nanotechnology; Physics
Quantum Dots, Nanocrystals, Synthesis, Characterization, PbS, Iron bromide, Iron pyrite, Solar Cell, Schottky junction, Heterojunction, Back contact, UPS, XPS, Work function, Band offset, LCA, Meta-analysis, Embedded energy, EPBT, EROI

Recommended Citations

Citations

  • Bhandari, K. P. (2015). Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430327894

    APA Style (7th edition)

  • Bhandari, Khagendra. Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics . 2015. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430327894.

    MLA Style (8th edition)

  • Bhandari, Khagendra. "Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics ." Doctoral dissertation, University of Toledo, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430327894

    Chicago Manual of Style (17th edition)

toledo1430327894
760
© 2015, some rights reserved.Creative Commons License Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics by Khagendra P Bhandari is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Toledo and OhioLINK.