SOLAR CELLS ON MY MIND - web.missouri.eduweb.missouri.edu/~glaserr/3700s13/SP13A06_Gold.pdf ·...

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


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


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)


Images courtesy of: Wikipedia

Addi5on of Sulfur

•  (1 eq) Sulfur added to ether solution (warmed and stirred)

Image courtesy of: Wikipedia


Addi5on of p-‐Toluenesulfonyl chloride

•  (1 eq) of p-Toluenesulfonyl chloride (TsCl) mixed into solution (warmed and stirred).



Dilithia5on with n-‐BuLi

•  Product is present but not isolated. •  Therefore, n-BuLi slowly added to solution

(stirred and refluxed for one hour).



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


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


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