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Developing new photovoltaic cells based on polimeric materials on flexible support


Programme: CEEX – RELANSIN

Contract no. : 105/03.10.2005

Project period : 30.10.2005 – 30.03.2008

Project coordinator :
Institutul Naţional de Cercetare Dezvoltare pentru Textile şi Pielarie – Bucuresti

– Universitatea "Politehnica"din Bucuresti
– Institutul National Cercetare-Dezvoltare pentru Microtehnologie (IMT-Bucuresti)
– Institutul de Cercetare si Proiectare pentru Electrotehnica
– Universitatea din Bucuresti
– Institutul National Cercetare-Dezvoltare de Fizica Laserilor , Plasmei si Radiatiei -INCDFLPR
– Institutul Naţional de Cercetare–Dezvoltare pentru Chimie şi Petrochimie- ICECHIM

Project objective:
The main project objective was built by the developing of technologic processes of obtaining solar cells on flexible backings.

Specific objectives:
- the studying, elaborating and characterizing of the processes of conductive polymer synthesis for photovoltaic applications;
- Syntheses of new chromophores and the evaluating of the photovoltaic activity in solar cells;
- the elaborating and characterizing of laying on techniques for photovoltaic applications
- the developing of technological processes of obtaining solar cells on flexible backing
- fundamental studies on conversing the photovoltaic energy into synthetized dyes and polymers
- fundamental studies on photovoltaic structures
- the result dissemination by publishing articles and/or delivering reports at scientific conferences

Project realisation plan - stages:
I: Thematic network creation and polymers preliminaries expriments for photovoltaic applications
II. Studies and laboratory experiments of the polymers synthesis for photovoltaic applications.
III. Processes experiments for polymers and dyes synthesis for photvoltaic applications –optimizations and compatibility processes.
IV. Experiments for combined synthesis of the polymeric materials –dyes for photovoltaic application
V. Synthesis/characterization of polymers and depositions techniques for photovoltaic application
VI. Optimization/compatibility of the processes for solar cells based on polymers
VII. Measurements/analysis/characterization. Process and photovoltaic structures evaluation.

1. Syntheses and characterizations of conductive polymers:
- the developing of the methods of polymerization in emulsion and physical-chemical opto-electronic characterization of the polyanilines doped with hydrochloric acid, p-toluenesuphonic(p-TS) acid, dodecylbenzenesulphonic(DBS) acid, dodecylhydrogensulphuric acid
- the preparing of blends of polyanilines /DBS/polyacrylate; polyanilines/DBS; /poly(methyl-methacrylate); polyanilines/DBS /polyurethanes;
- syntheses and physical – chemical characterizing, the opto-electronics of polypyrroles, of pyrrole co-oligomers/2,1,3-benzothiadiazole.
There was studied the influence of the reaction parameters over the aniline polymerization process: the molar ratio aniline: persulphate:hydrocloric acid (DBS,p-TS), pH, acid concentration, temperature and reaction duration. The elaborating of a technology of synthesizing the water and organic solvent soluble polyanilines was successful, the fact that polyaniline is a water and organic solvent practically insoluble polymer being quite known. The technology of synthesizing the polypyrrole by oxidizing the pyrrole with ammonium persulphate in the presence of the polyelectrolytes having the function of dopant and surfactant that can disperse in water and organic solvents was elaborated. These conductive polymers can be widely applied from optoelectronics to medical applications.

2. Dye synthesis:
- synthesis and characterization of phtalocyanines containing peripheral functional groups with non-linear optical properties: copper, cobalt, nickel, zinc and aluminium phtalocyanines, by the direct substitution of the tetra-isoindole macrocycle.
An original method of obtaining the tetra-sulphonated compounds of phtalocyanines, of a high purity by using the chlorosulphonic acid as a sulphonation agent was perfected.
- the grafting of substitutes on the phtalocyaninic macromolecule for increasing the absorbtion domain: the synthesis and characterizing of six dyes with mixed aso-phtalocyaninic chromophore, that are outstandingly sensitive and promising for the utilization in the solar cell field, owing also to the high absorbtion wave length, which is situated in the vecinity of the infrared domain having a remarkable stability (over 2900C);
- the grafting of substitutes on the phtalocyaninic macromolecule for increasing the solubility and the photovoltaic activity: there were synthesized and characterized Cu, Ni, Co, Fe and Zn phtalocyanines, which are water soluble, by grafting a carboxyl group on the four phenylic nuclei from the phtalocyaninic macrocycle;
- chloromethilation of phtalocyanines by using as a reactant of bis-chloromethyl ether, in situ syntheiszed by the reaction between paraphormaldehyde and chlorosulphonic acid. The original character resides in the introducing of paraphormaldehyde into the reaction system before adding the chlorosulphonic acid, a thing that makes the concurrent sulphonation reaction be practical inhibited.
- TEMPLATE synthesis and the characterization of 7 new oleophilic phtallocyanines: original synthesis method of 4-nitrophatalonitrile, a key intermediate agent in the process of obtaining the substitute phtallocyanines. The original method of obtaining the phtalonitriles substituted with alkoxy groups from the adequate nitro-derivatives.
- The synthesis of six dyes with mixed azoic and phtallocyaninic chromophore. The intermediate agent that laid at the basis of their obtaining is a new compound obtained by the compactly condensed grafting of certain thiazolic cycles on the phtallocyaninic macrocycle;
- the amino-thiazolo-phtalocyanine synthesis, non-cited compounds from the specialty literature, was carried out starting from 4-nitro-phtalonitrile, which was condensed with a view to obtaining the tetra-nitro-phtalocyanine. By sodium sulphide reduction there was obtained the tetra-amino phtalocyanine, whiuch was subjected to a thiazolation reaction in the presence of the sodium thyocianate and of the sulphuryl chloride as oxidizer. The synthesized compounds were characterized by elemental analysis, IR and UV-VIZ spectroscopy.
- The reduction of tetra-nitro-phtallocyanines in tetra-amino phtallocyanines was done by an original method, by using N,N-dimethyl-formamide as a solvent.
- The synthesizing and characterizing of water soluble phtallocyanines by grafting a carboxyl group on the 4 phenilic nuclei from the phtallocyanine macrocycle.
- the synthesis of 4 tetra phenyl porphyrin compounds by grafting substitutes on the porphyrin macrocycle for increasing solubility and photovoltaic activity.

3. Technologic tests of applying conductive polymers and dyes on glass and flexible sub-layers: there were elaborated the following methods of laying thin transparent and conductive layers with electrode role:
- laser ablation (PLD): transparent and conductive films with uniform and compact ITO and TiO2 distribution, on glass and plastic sub-layers, with a stoichiometry similar to that of the target they come from, at room temperature, for an oxygen pressure range of 10-60 mTorr; thermal treatments at over 250 - 350 oC.
- sputtering in radiofrequency, at room temperature and oxygen optimum presure of 30 mbar, of thin simple and porous TiO2 films, on glass and ITO sublayers. Multilayer (sandwich) films were made in the following versions: TiO2 standard/glass, TiO2 standard/ITO, TiO2 porous/TiO2 standard/ITO/glass with 70-96 % transmissions depending on the layer thickness, sublayer and refraction indices of each layer.
- thermal evaporation in vacuum, followed by anodic oxidation: conductive and transparent thin layers (~ 300 - 420 nm) of In2O3 oxide doped with Sn (ITO) by oxidizing the In and Sn layers; thin layers (150-300 nm ) of ZnO; porous nanostructured TiO2 layers on glass /ITO sublayer and on flexible/ITO sublayer with ~100nm thickness.
- printing: the layers obtained by screen printing the TiO2 nanoparticle pastes with the help of polyamide screen stencil, are uniform, with thickness ranging between 10 μm - 30 μm
- spin coating: the method is advantageous because transparent conductive fillms on large areas can be obtained, the used equipment is simple, productivity is high and the transparent conductive film can be produced at costs lower than by the sputtering method. Polyaniline thin layers were obtained on ITO/glass or ZnO/glass sublayer.
- soil-gel: porous TiO2 thin films were obtained, with air inclusions and the transmittance of over 80 % in the visible domain;
- cyclical voltametry (electrochemical polimerization) of aniline in potentiostatic regime: there were obtained thin layers of the emeraldine base type at a potential of > 0,8 V (SCE) and various thickness layers, formed of salt blend (green colour) and emeraldine base (blue colour) at a lower potential 0,6 – 0,8 V, in a longer while. The PANI layers prepared by cyclical voltametry can be used for achieving solar cells with homojunction if the polymer is doped, both of the p type and of the n type, haeterojunction between this polymer and an anorganic semi-conductor or with the Schottky barrier .

4. Types of obtained photovoltaic cells:

5. The developing of a specific web site with the observing of confidentiality for facilitating the joint research activities, which can be accessed from the pages:
INCDTP: www.certex.ro – Romana; - RETEA TEMATICA – Noi sisteme fotovoltaice pe baza de sisteme polimerice pe substraturi flexibile – SOLAR (Romanian; - THEMATIC NETWORK – New photovoltaic systems containing polymer systems on flexible sublayers – SOLAR)

6. The project results were disseminated by means of scientific reports, articles in specialty publications.

Scientific presentations:
1. F. Iacomi*, M. Purica**, E. Budianu**, D. Macovei***, Synthesis of the transparent and conductive CdS thin films for optoelectronic devices applications, Proceedings of International Semiconductor Conference, 3-5 Oct. 2005, Sinaia, Romania, IEEE Catalog Number 05TH8818, ISBN 0-7803-9214-0, pag. 161-165
2. E. Manea, E. Budianu, M. Purica, C. Podaru, I. Cernica, A. Coraci, F. Babarada, Silicon solar cells technology using honeycomb textured front surface, Proceedings of International Semiconductor Conference, 3-5 Oct. 2005, Sinaia, Romania, IEEE Catalog Number 05TH8818, ISBN 0-7803-9214-0, pag. 157-161
3. M. Danila1, I. Licea2, M.Purica1, Light absorption in nanostructured crystalline ZnO thin films, Proceedings of International Semiconductor Conference, 3-5 Oct. 2005, Sinaia, Romania, IEEE Catalog Number 05TH8818, ISBN 0-7803-9214-0, pag. 77- 81.
4. I. Dumitrescu, A.M. Mocioiu, Celule solare flexibile, Simpozion SCCCR, 08.12.2005, INCDTP, Bucuresti
5. I. Dumitrescu, A.M. Mocioiu, Polimeri conductivi, Simpozion “ Produse textile pentru domenii speciale, 7-8.09.2006, INCDTP, Bucuresti
6. Iuliana Dumitrescu, Ana Maria Mocioiu, Dezvoltarea de noi sisteme fotovoltaice pe baza de materiale polimerice pe substraturi flexibile, CONFERINŢA “CERCETAREA DE EXCELENŢĂ – PREMIZĂ FAVORABILĂ PENTRU DEZVOLTAREA SPAŢIULUI ROMÂNESC DE CERCETARE, 22 – 24 oct. 2006, Brasov
7. Iuliana Dumitrescu, Ana Maria Mocioiu, Conductive polymers for intelligent clothes, Book of proceedings, The International Conference on Intelligent Textiles 2006, November 12–14, 2006, the Hoam Convention Center, Seoul National University, Seoul, Korea
8. Ana Maria Mocioiu, Iuliana Dumitrescu, “Experiments to Obtain Flexible Solar Cells for Clothes”, 8th International Symposium on Green Chemistry in China (8th ISGCC’2007, Beijing, China from 21 - 24 May 2007
9. Iuliana Dumitrescu, Ana Maria Mocioiu, Synthesis of Soluble Polyaniline, Conferinta CEEX, 24 – 26 oct. 2007, Brasov
10. Ana-Maria Mocioiu, Iuliana Dumitrescu, Composites of conductive polymers –
coated fabrics, - “Fibre Reinforced Composites Conference 2007”, Port Elizabeth, South Africa 9 – 12 December 2007
11. Paula Obreja, Dana Cristea, Munizer Purica, Teodora Ignat, Raluca Gavrila, “Polyaniline films for sensor applications”, European Congress on Advanced Materials and Processes, Nuremberg, Germany, 10-13 September 2007
12. E.Manea, E.Budianu, M.Purica, C.Podaru, A. Popescu, C. Parvulescu, A. Dinescu, A. Coraci, I. Cernica, F. Babarada, "Front surface texturing processes for silicon solar cells”, pp. 191-194, Proc. of International Semiconductor Conference - CAS 2007, October 15-17, 2007, Sinaia, Romania, IEEE Catalog Number 07TH8934
13. B. Mitu, G. Epurescu, G. Dinescu, M. Dinescu, E. Budianu, M. Purica, “Zinc oxide thin films deposited by pulsed laser technique for optoelectronic devices application”, Symposium D, E-MRS 2007 Spring Meeting, Strasbourg, France, May 28 to June 1, 2007
14. I.Dumitrescu, G. Grigoriu, Perspective ale utilizarii energiilor regenerabile in industria textila, 18 - 20 iunie 2008, Bucuresti, CCIB
15. I.Dumitrescu, A.M. Mocioiu,C. Nicolae, Flexible electronics, “EXCELLENCE RESEARCH – A WAY TO INNOVATION”, Brasov, ARO – PALACE HOTEL, 27 - 29 July 2008
16. I.Dumitrescu, A.M. Mocioiu, G. Constantin, C. Boscornea, M. Purica, Metode de realizare a straturilor de TiO2 pe suporturi de sticla/ITO, Solar & Wind International Conference “SWIC 2008”, the sixth edition in a series of European meetings on renewable energy sources, the Test Site Facility ICPE –- Agigea, 28-30 July 2008
17. Constantin Grigoriu*, Gabriel Prodan**, Victor Ciupina**, Constantin Logofatu***, “Oxide nanoparticles produced by pulsed laser ablation”, Cornelia Sima*, Cristian Viespe*, E-MRS 2007 Fall Meeting, Warsaw (Poland), 17-21 September (2007)
19. Cornelia Sima1, Cristian Viespe1, Constantin Grigoriu1, Mihai Vlaicu2 , “Study of TiO2 thin films deposited by advanced pulsed laser deposition method on ITO”, Grecia 22-26 oct 2008
20. I. M. Oancea Stanescu, V. Ciupina, G. Prodan, M. Prodan, C. Grigoriu and C. Sima, “Characterization of TiO2 nanoparticles by electron microscopy” 6 th International Student Conference of the Balkan Physical Union, ISCBPU-6, Bodrum-Turkey, 21-25 August 2008

Published papers :
1. F. Iacomi*, M. Purica**, E. Budianu**, D. Macovei***, Transparent and conductive CdS Thin Films-Preparation and Structural and Optical investigation, Acceptata pentru publicare in Romanian Journal of Information Science and Technology, editata Academia Romana.
2.F. Iacomi, M. Purica, E. Budianu, P. Prepelita, D. Macovei, “Structural studies on some doped CdS thin films deposited by thermal evaporation”, Thin Solid Films 515, p. 6080-6084, 2007. 2. L. Isfan, St. Tomas, C. Pop, C. Boscornea, R. Mocanu Ionescu, „Sinteza unui colorant azometinic obtinut prin ciclotetramerizarea unui ftalodinitril substituit de un rest azometinic”, Rev. Chim., 2007, (in press).
3. Cristian Boscornea, Nicoleta Grigoriu, Doina Tărăbăşanu Mihăilă, Monica Robu “Obţinerea coloranţilor ftalocianinici prin metode solvotermale” Rev. Chim., 2007
4. Munizer Purica, F. Iacomi, C. Baban, N. Apetroaei, D. Mardare, D. Luca, Investigation of structural properties of ITO thin films deposited on different substrates, Thin Solid Films 515 (2007) pag. 8674-8678.
5. C. Viespe, C. Grigoriu, M. Popescu, M. Sava, A. Lorenczi, A. Velea, S. Zamfira “Cristalization of PLD deposited ITO thin films by thermal treating in various gas environment” Journal of Optoelectronics and Advanced Materials 9 (11), 3563-2566, nov 2007
6. Cornelia Sima, Wolfgang Waldhauser, Juergen Lackner, Markus Kahn, Ionut Nicolae, Cristian Viespe, Constantin Grigoriu, “Properties of TiO2 thin films deposited by RF magnetron sputtering”, Journal of Optoelectronics and Advanced Materials Vol.9, No. 5, May (2007), pag 1446-1449
7. Cristian Viespe, Ionut Nicolae, Cornelia Sima, Constantin Grigoriu, Rares Medianu, “ITO thin films deposited by advanced pulsed laser deposition” , Thin Solid Films, 515 (2007) 8771-8775
8. 1. L. Ișfan, , Ş. Tomas, C. Pop, , C. Boscornea, , R. Mocanu-Ionescu, .”Sinteza şi caracterizarea unei serii de derivaţi de tetra-hidrazono ftalocianine de cupru condensate cu diverse aldehide aromatice”, Revista de Chimie 58 (10), pp. 941-944, 2007
9. L. Ișfan, , Ş. Tomas, C. Pop, , C. Boscornea, , R. Mocanu-Ionescu, “Synthesis of some Schiff-base of copper tetraaminophtalocyanine derivates” Revista de Chimie, 58 (7), pp. 664-668, 2007.
10. D. Donescu, C. Radovici, Cristiana Bercu, M. Ghiurea, C. Boscornea “Efectul templantilor asupra obtinerii unor hibride bioxid de titan-ftalocianina”, Materiale Plastice, 44(1), 7-13, 2007
11. L. Ișfan, , Ş. Tomas, C. Pop, , C. Boscornea, , R. Mocanu-Ionescu, “Synthesis and characterization of an azomethine-phthalocyanine cromophore by cyclotetramerization of substituted phtalodinitrile with azomethinic remainder” Revista de Chimie, , 58 (8), pp. 830-832, 2007
12.P. Obreja, D. Cristea, M. Purica, R. Gavrila, F. Comanescu, “Polymers doped with metal oxide nanoparticles with controlled refractive index”, Polymery, 2007, 52, nr. 9.
13. E. Budianu, M. Purica, F. Iacomi, C. Baban, P. Prepelita and E. Manea , “Silicon metal-semiconductor–metal photodetector with zinc oxide transparent conducting electrodes”, Thin Solid Films, 516, p. 1629-1633, 2008.
14. Cristian Boscornea, Nicoleta Grigoriu, Doina Tărăbăşanu Mihăilă, Monica Robu "Obţinerea coloranţilor ftalocianinici prin metode solvotermale" Rev. Chim., 59(4), pp. 371-375, 2008
15. “Production of Oxide Nanoparticles by Pulsed Laser Ablation” Cornelia Sima*, Cristian Viespe*, Constantin Grigoriu*, Gabriel Prodan**, Victor Ciupina** , Journal of Optoelectronics and Advanced Materials 2008
16.” TiO2 thin films deposited by pulsed laser deposition method”, C. Sima*, C.Viespe*, C. Grigoriu*, M. Vlaicu**, I. Pasuk**, Journal of Optoelectronics and Advanced Materials 2008