Application of Nanostructured Materials and Multi-junction Structure in Polymer Solar Cells

Handle URI:
http://hdl.handle.net/10754/583818
Title:
Application of Nanostructured Materials and Multi-junction Structure in Polymer Solar Cells
Authors:
Gao, Yangqin ( 0000-0002-2486-6621 )
Abstract:
With power conversion efficiency surpassing the 10% milestone for commercialization, photovoltaic technology based on solution-processable polymer solar cells (PSCs) provides a promising route towards a cost-efficient strategy to address the ever-increasing worldwide energy demands. However, to make PSCs successful, challenges such as insufficient light absorption, high maintenance costs, and relatively high production costs must be addressed. As solutions to some of these problems, the unique properties of nanostructured materials and complimentary light absorption in multi-junction device structure could prove to be highly beneficial. As a starting point, integrating nanostructure-based transparent self-cleaning surfaces in PSCs was investigated first. By controlling the length of the hydrothermally grown ZnO nanorods and covering their surface with a thin layer of chemical vapor-deposited SiO2, a highly transparent and UV-resistant superhydrophobic surface was constructed. Integrating the transparent superhydrophobic surface in a PSC shows minimal impact on the figure of merit of the PSC. To address the low mechanical durability of the transparent superhydrophobic surface based on SiO2-coated ZnO nanorods, a novel method inspired by the water condensation process was developed. This method involved directly growing hollow silica half-nanospheres on the substrate through the condensation of water in the presence of a silica precursor. Benefit from the decreased back scattering efficiency and increased light transport mean free path arise from the hollow nature, a transparent superhydrophobic surface was realized using submicrometer sized silica half-nanospheres. The decent mechanical property of silica and the “direct-grown” protocol are expected to impart improved mechanical durability to the transparent superhydrophobic surface. Regarding the application of multi-junction device structure in PSCs, homo multi-junction PSCs were constructed from an identical polymer absorber, in which the homo-tandem device showed an enhanced power conversion efficiency (PCE) (8.3% vs 7.7%) relative to the optimized single junction PSC. The high open voltage (>1.8 V) achieved in homo-tandem PSCs allowed for water splitting with an estimated solar-to-fuel conversion efficiency of 6%. Lastly, a hybrid tandem cell was also constructed using a polymer and a colloidal quantum dot subcell. Different hybrid tandem device architectures were proposed and show a promising PCE of 6.7%.
Advisors:
Beaujuge, Pierre
Committee Member:
Bakr, Osman M. ( 0000-0002-3428-1002 ) ; Ooi, Boon S. ( 0000-0001-9606-5578 ) ; Sargent, Edward H.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program
Program:
Materials Science and Engineering
Issue Date:
9-Dec-2015
Type:
Dissertation
Appears in Collections:
Dissertations; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.advisorBeaujuge, Pierreen
dc.contributor.authorGao, Yangqinen
dc.date.accessioned2015-12-13T09:15:52Zen
dc.date.available2015-12-13T09:15:52Zen
dc.date.issued2015-12-09en
dc.identifier.urihttp://hdl.handle.net/10754/583818en
dc.description.abstractWith power conversion efficiency surpassing the 10% milestone for commercialization, photovoltaic technology based on solution-processable polymer solar cells (PSCs) provides a promising route towards a cost-efficient strategy to address the ever-increasing worldwide energy demands. However, to make PSCs successful, challenges such as insufficient light absorption, high maintenance costs, and relatively high production costs must be addressed. As solutions to some of these problems, the unique properties of nanostructured materials and complimentary light absorption in multi-junction device structure could prove to be highly beneficial. As a starting point, integrating nanostructure-based transparent self-cleaning surfaces in PSCs was investigated first. By controlling the length of the hydrothermally grown ZnO nanorods and covering their surface with a thin layer of chemical vapor-deposited SiO2, a highly transparent and UV-resistant superhydrophobic surface was constructed. Integrating the transparent superhydrophobic surface in a PSC shows minimal impact on the figure of merit of the PSC. To address the low mechanical durability of the transparent superhydrophobic surface based on SiO2-coated ZnO nanorods, a novel method inspired by the water condensation process was developed. This method involved directly growing hollow silica half-nanospheres on the substrate through the condensation of water in the presence of a silica precursor. Benefit from the decreased back scattering efficiency and increased light transport mean free path arise from the hollow nature, a transparent superhydrophobic surface was realized using submicrometer sized silica half-nanospheres. The decent mechanical property of silica and the “direct-grown” protocol are expected to impart improved mechanical durability to the transparent superhydrophobic surface. Regarding the application of multi-junction device structure in PSCs, homo multi-junction PSCs were constructed from an identical polymer absorber, in which the homo-tandem device showed an enhanced power conversion efficiency (PCE) (8.3% vs 7.7%) relative to the optimized single junction PSC. The high open voltage (>1.8 V) achieved in homo-tandem PSCs allowed for water splitting with an estimated solar-to-fuel conversion efficiency of 6%. Lastly, a hybrid tandem cell was also constructed using a polymer and a colloidal quantum dot subcell. Different hybrid tandem device architectures were proposed and show a promising PCE of 6.7%.en
dc.language.isoenen
dc.subjectSelf-cleaningen
dc.subjectMulti-junctionen
dc.subjectPolymer Solar Cells (PSCs)en
dc.subjectBreath Figureen
dc.subjectHollow Structureen
dc.subjectHalf- nanosperesen
dc.titleApplication of Nanostructured Materials and Multi-junction Structure in Polymer Solar Cellsen
dc.typeDissertationen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMaterials Science and Engineering Programen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberBakr, Osman M.en
dc.contributor.committeememberOoi, Boon S.en
dc.contributor.committeememberSargent, Edward H.en
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id101908en
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.