Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


SunY.dis (final).pdf (5.15 MB)

ETD Abstract Container

Abstract Header

Controlled Morphology in Bulk Heterojunction Polymer and Perovskite Solar Cells

Sun, Yan
http://orcid.org/0000-0003-4187-4591
http://rave.ohiolink.edu/etdc/view?acc_num=akron1474721380738042

Abstract Details

2016, Doctor of Philosophy, University of Akron, Polymer Engineering.
Bulk heterojunction (BHJ) polymer solar cells constitute an emerging approach to a low cost, solution processable, and highly scalable renewable energy avenue. However, one of the major challenges limiting the broad applicability of these solar cells is their lower device efficiencies compared to their inorganic counterparts. In this regard, much effort has been dedicated to optimizing the efficiencies by developing new high-performance materials and fine tuning the BHJ blend morphology via various processing methods. This study presents a molecular level understanding of what controls the device performance. In the first part, a novel fulleropyrrolidine derivative C60-fused N-(3-methoxypropyl)-2-(carboxyethyl)-5-(4-cyanophenyl) fulleropyrrolidine (NCPF) was synthesized and blended with a conjugated polymer poly(3-hexylthiophene) (P3HT) for applications of BHJ polymer solar cells. NCPF has a good solubility in common organic solvents and comparable electronic properties with the widely used acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). A short term thermal annealing induced enhancement in device performance was found to be associated with improved crystallization of polymer within blend thin films and correspondingly increased hole mobility. The long term annealing study showed that P3HT:NCPF blends had superior thermal stability compared to P3HT:PCBM blends. In the second part, we demonstrate the compatibilization effect of a rod-coil block copolymer (BCP) in different polymer:fullerene derivative blend systems. AFM results and GIWAXS analyses revealed that the addition of BCP into the blend thin films effectively altered the thin film nanostructure and polymer crystalline structure. Moreover, higher device efficiencies were obtained in blends containing block copolymer compatibilizer. The improvement in performance was then ascribed to the morphological changes in the polymer:fullerene blends. The final study deals with the application of a simple, high throughput and roll-to-roll compatible process, zone annealing, to process polymer:fullerene BHJ blends. By morphological study, we established a regime in which interpenetrating phase separated morphology was obtained via zone annealing that exhibited no overgrown fullerene crystallites. Moreover, we extend the use of zone annealing method to perovskite materials, i.e. inorganic–organic hybrid lead halide perovskites. The zone annealed perovskite film morphology exhibits a transition from densely packed structures to dendritic crystallizations with increasing sample annealing velocity. This transition shifts to lower speed in higher temperature condition. By varying temperature and the sweeping speed, large grains were observed in zone annealed samples. Collectively, these studies provide a more fundamental and deeper understanding of the relationships between materials, processing, morphology and performance of thin film solar cells.
Alamgir Karim, Dr. (Advisor)
Xiong Gong, Dr. (Committee Member)
Kevin Cavicchi, Dr. (Committee Member)
Yu Zhu, Dr. (Committee Member)
Peter Niewiarowski, Dr. (Committee Member)
162 p.
Energy; Engineering; Materials Science; Nanotechnology; Polymers

Recommended Citations

Citations

  • Sun, Y. (2016). Controlled Morphology in Bulk Heterojunction Polymer and Perovskite Solar Cells [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1474721380738042

    APA Style (7th edition)

  • Sun, Yan. Controlled Morphology in Bulk Heterojunction Polymer and Perovskite Solar Cells. 2016. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1474721380738042.

    MLA Style (8th edition)

  • Sun, Yan. "Controlled Morphology in Bulk Heterojunction Polymer and Perovskite Solar Cells." Doctoral dissertation, University of Akron, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1474721380738042

    Chicago Manual of Style (17th edition)

akron1474721380738042
273
© 2016, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.