This document discusses impedance characterization for dye-sensitized solar cells. It first describes the preparation of a standard Grätzel cell, which involves depositing a nanoporous TiO2 layer and dye on a conductive glass substrate. Next, impedance spectroscopy is introduced as a method to characterize and model the cell by measuring its response to alternating currents at different frequencies. Key parameters like series resistance, recombination resistance, and diffusion resistance can be extracted from the impedance spectra and correlated to cell performance at different potentials. The document concludes by mentioning future research directions involving new semiconductor photoelectrodes and solid-state solar cell designs.

1. Impedance Characterization for Dye-Sensitized Solar CellsSonia Ruiz RagaPhotovoltaic and Optoelectronic Devices GroupUniversitat Jaume I – Castelló – Spain http://www.elp.uji.es/

2. Introduction:Emergent DSC technology…… but first we have to go to the lab…

3. Introduction: Preparation of a standard Grätzel cell(1) Charachterization and modelling(2)(1) Wang, Q.; Ito, S.; Grätzel, M.; Fabregat-Santiago, F.; Mora-Sero´,I.; Bisquert, J.; Bossho, T.; Imai, H. J. Phys. Chem. B 2006, 110, 25210.(2) Chapter “Impedance spectroscopy: A general introduction and application to dye-sensitized solar cells”By J. Bisquert i F. Fabregat-Santiago in “Dye sensitized solar cells”Edited by K. Kalyanasudaram, EPFL press, Laussane, Switzerland (2010) ISBN: 978-2-940222-36-0 Distribution: CRC Press, Boca Raton, FL, USA (2010) ISBN: 948-1-4398-0866-5

4. Preparation of a Grätzel cell:Ingredients:Ruthenium-based DyeFTO glassSurlyn (thermoplastic polymer)Ti-isopropoxidesolutionChloroplatinic acidNanoparticle TiO2 pasteI- / I 3- electrolyte

5. Preparation of a Grätzel cell:1- Clean the TCO glass3- Deposite the working electrode of nanoporous TiO2 paste450º2- Deposite a compact layer of TiO2 by spray pirolisisTiO2-isopropoxide solution

6. Preparation of a Grätzel cell:4- Calcinate at 450º during 30 min5- Dip in dye solution overnight6- Prepare the Pt counter - electrodeChloroplatinic acid450ºC

7. Preparation of a Grätzel cell:7- Seal the device8- Fill with electrolyteSurlyn (thermoplastic polymer)9- Weld Sn contacts

8. Device completed!Nanoporous TiO2 layerGlass substratAdsorbed DYEFTO layerI- / I3- electrolyteCompact TiO2 layerPt counter electrode

9. Characterization and modelling:

10. J – V curve:The generation gives the photocurrentOpen-circuit voltage is determined by energetic of the materials and recombinationThe fill factor gives the reduction of the power with respect to:

11. Impedance Spectroscopy:SolutionSolidHigh frequencyLow frequency

12. Impedance Spectroscopy:

13. Impedance Spectroscopy:RsRcoRctRtRPtCcoCµZdRblCPtCbl

14. Characterization and modelling:RsRcoRctRtRPtCcoCµZdRblCPtCbl

15. Characterization and modelling:Low potentials[0 – 0.300] VSeries resistance

16. Counter electrode resistance & capacitance

17. Blocking layer resistance & capacitance Characterization and modelling:Medium potentials[0.300 – 0.600] VSeries resistance

18. Counter electrode resistance & capacitance

19. Transmission line: - Transport resistance in TiO2- Recombination resistance & capacitance of TiO2Electrolyte diffusion resistance (not always) ?

20. Characterization and modelling:High potentials[0.600 – 0.900] VSeries resistance