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SOLAR CELLS ON MY MIND
Dye-Sensitized Solar Cell (DSSC) “Grätzel cells”
• Consists of 2 conducting glass electrodes stacked on top of another
• Produces electricity through electron transfer • Dye absorbs photons of light, takes an electron to excited
state – e- reaches counter electrode
• Dye molecule (less an e-) obtains e- from iodine electrolyte (back to ground state)
Courtesy of: Center for the Advancement of Mathema5cs and Science Educa5on (CAMSE) h;p://www.camse.org/scienceonthemove/documents/DSSC_manual.pdf
Organic DSSCs • Organic dyes work much like how certain plants/algae convert sunlight into energy
• Great promise as inexpensive alterna5ve to costly silicon-‐based solar cells Courtesy of: Center for the Advancement of Mathema5cs and Science Educa5on (CAMSE) h;p://www.camse.org/scienceonthemove/documents/DSSC_manual.pdf
Most Interesting Man in the World
Courtesy of Google Images
Dithieno[2,3-b:3’,2’-d]thiophene (DTT)
• Attractive properties: – High electron delocalization – Great aromatic resonance energy disruption
• DTT: extremely insoluble – Must incorporate other functional groups
• Typically aklyl chains
Cevher, Sevki Can, Naime Akbasoglu Unlu, Ali Can Ozelcaglayan, Dogukan Hazar Apaydin, Yasemin Arslan Udum, Levent Toppare, and Ali Cirpan. "Fused Structures in the Polymer Backbone to Inves5gate the Photovoltaic and Electrochromic Proper5es of Donor–acceptor-‐type Conjugated Polymers." Journal of Polymer Science (2013): 1-‐9. Print.
Components of DTT
• Donor fragment • π-conjugated linking segment • Acceptor fragment
• Helps achieve broad and intense absorption in visible spectrum
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors."Organic Electronics 11.5 (2010): 801-‐13. Web.
Uses of DTT
• Electroluminescence • Two-photon absorption and excited fluorescence • Nonlinear optical chromophores • Photochromism • Organic thin-film transistor (OTFT) • Organic photovoltaic (OPV) applications
• Applications in everyday electronic and optical devices
Li, Jen, Huei-‐Shuan Tan, Zhi-‐Kuan Chen, Wei-‐Peng Goh, Hoi-‐Ka Wong, Kok-‐Haw Ong, Weiling Liu, Chang Ming Li, and Beng S. Ong. "Dialkyl-‐Subs5tuted Dithienothiophene Copolymers as Polymer Semiconductors for Thin-‐Film Transistors and Bulk Heterojunc5on Solar Cells." Macromolecules 44.4 (2011): 690-‐93. Print.
Concentrations of DTT
• Dithienothiphene-based polymers as acceptors in a 1:1 ratio with polythiophene derivatives as a donor
• Optimized power conversion efficiency of 1.5% can be achieved by increasing the donor/acceptor weight ratio to 3:1
Zhan, Xiaowei, Zhan'ao Tan, Erjun Zhou, Rajneesh Mirsa, Adrian Grant, Xiao-‐Hong Zhang, Zesheng An, Bernard Kippelen, and Seth R. Marder. "Copolymers of Perylene Diimde with Dithienothiphene and Dithienopyrrole as Electron-‐transport Materials for All-‐polymer Solar Cells and Field-‐effect Transistors." Journals of Material Chemistry 19 (2009): 5794-‐803. Print.
Hazards
• Toxicological properties of this sensitizer must not be taken lightly
• Serious eye irritant • Toxic if swallowed • Respiratory tract irritation • Serious skin irritation
"Material Safety Data Sheet (Dithieno[3,2-‐b:2',3'-‐D]thiophene)." Sigma-‐Aldrich. Sigma-‐Aldrich Co., 12 Dec. 2011. Web. 04 Mar. 2013. <h;p://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US>.
1H-NMR
• Pair of doublets • Aromatic region • Four protons
1
2
1H-‐NMR, 13C-‐NMR of Dithieno[3,2-‐b:2',3'-‐d]thiophene. Substance Detail: SciFinder. h;ps://scifinder.cas.org/scifinder/view/scifinder/scifinderExplore.jsf
Courtesy of Google Images
13C-NMR
• Four different Carbons
1
2
3
4
1H-‐NMR, 13C-‐NMR of Dithieno[3,2-‐b:2',3'-‐d]thiophene. Substance Detail: SciFinder. h;ps://scifinder.cas.org/scifinder/view/scifinder/scifinderExplore.jsf
IR Spectra
• Onset near 600 nm • π-spacer allows for
increased absorption past 700 nm
• Maximum intensity at 795 nm
Ku, Sung-‐Yu, Christopher D. Liman, Daniel J. Burke, Neil D. Treat, Jus5n E. Cochran, Elizabeth Amir, Louis A. Perez, and Craig J. Hawker. "A Facile Synthesis of Low-‐Band-‐Gap Donor–Acceptor Copolymers Based on Dithieno[3,2-‐b:2ʹ′,3ʹ′-‐d]thiophene." Macromolecules 44.24 (2011): 9533-‐538. Print.
Voltammogram
• Voltammograms of two DTT structures • Varied the substituents in P1 and P2
Cevher, Sevki Can, Naime Akbasoglu Unlu, Ali Can Ozelcaglayan, Dogukan Hazar Apaydin, Yasemin Arslan Udum, Levent Toppare, and Ali Cirpan. "Fused Structures in the Polymer Backbone to Inves5gate the Photovoltaic and Electrochromic Proper5es of Donor–acceptor-‐type Conjugated Polymers." Journal of Polymer Science (2013): 1-‐9. Print.
Voltammogram Graph
• Derived on ITO electrode in 0.1 M TBAPF6/CAN
• Measures current density vs potential during oxidation and reduction
• HUMO and LUMO levels estimated
Cevher, Sevki Can, Naime Akbasoglu Unlu, Ali Can Ozelcaglayan, Dogukan Hazar Apaydin, Yasemin Arslan Udum, Levent Toppare, and Ali Cirpan. "Fused Structures in the Polymer Backbone to Inves5gate the Photovoltaic and Electrochromic Proper5es of Donor–acceptor-‐type Conjugated Polymers." Journal of Polymer Science (2013): 1-‐9. Print.
One-Pot [2 + 1] synthesis of dithienothiophene
Here’s our product! Follow me, the “Science
Guy,” on this synthetic process!
Picture Courtesy of www.americanhumanist.org
One-Pot [2 + 1] synthesis of dithienothiophene
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Lithiation to Remove 2-bromobutane
• (2 eq) 3-bromothiophene is lithiated with (2 eq) n-butyllithium (n-BuLi)
• Vacuum filtration removes 2-bromobutane (C4H9Br)
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Images courtesy of: Wikipedia
Addi5on of Sulfur
• (1 eq) Sulfur added to ether solution (warmed and stirred)
Image courtesy of: Wikipedia
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Addi5on of p-‐Toluenesulfonyl chloride
• (1 eq) of p-Toluenesulfonyl chloride (TsCl) mixed into solution (warmed and stirred).
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Images courtesy of: Wikipedia
Dilithia5on with n-‐BuLi
• Product is present but not isolated. • Therefore, n-BuLi slowly added to solution
(stirred and refluxed for one hour).
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Images courtesy of: Wikipedia
Addition of Copper(II) chloride (CuCl2)
• CuCl2 added to solution, warmed to room temperature, and left to stir overnight.
• Excess time required for closure of third ring.
Image courtesy of: www.skylighter.com
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.
Final Purification Steps
• Solids removed next day by vacuum filtration. • Organic + ether layer is collected and purified – Column chromatography
• DTT recrystallized to light-yellow powder
Kim, Choongik, Ming-‐Chou Chen, Yen-‐Ju Chiang, Yue-‐Jhih Guo, Jangdae Youn, Hui Huang, You-‐Jhih Liang, Yu-‐Jou Lin, Yu-‐Wen Huang, Tarng-‐Shiang Hu, Gene-‐Hsiang Lee, Antonio Facchea, and Tobin J. Marks. "Func5onalized Dithieno[2,3-‐b:3',2'-‐d]thiophenes (DTTs) for Organic Thin-‐Film Transistors." Organic Electronics 11.5 (2010): 801-‐13. Web.