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Novel construction of CdTe solar cell based on polyketanil structure
Materials Science and Engineering B 165 (2009) 71–73
Contents lists available at ScienceDirect
Materials Science and Engineering B journal homepage: www.elsevier.com/locate/mseb
Novel construction of CdTe solar cell based on polyketanil structure a,∗ ´ ˛ b , Agnieszka Iwan b Maciej Sibinski , Zbigniew Lisik a , Danuta Sek a b
Department of Semiconductor and Optoelectronic Devices, Technical University of Łód´z, Poland Centre of Polymer and Carbon Materials, Polish Academy of Sciences, Zabrze, Poland
a r t i c l e
i n f o
Article history: Received 27 June 2008 Received in revised form 17 July 2009 Accepted 21 July 2009
a b s t r a c t A novel concept of CdS/CdTe solar cell structure utilisation for BIPV concept is reported. ICSVT as the base manufacturing technology is presented, in the background of its new properties investigation. Technological concepts of the cadmium telluride structure employment in its new application field are described. © 2009 Elsevier B.V. All rights reserved.
Keywords: Solar cell Thin film CdS/CdTe BIPV Polymer Polyimide
1. Introduction The classical CdS/CdTe solar cell structure is recognized as the very promising candidate for low-cost thin film solar modules [1,2]. Despite some production up-scaling problems these devices are at the level of the industrial manufacturing nowadays [3]. At this early stage, standardized CdS/CdTe modules production is mostly the aim of PV manufacturers, however, one should not forget cadmium telluride potential [4]. Based on the small thickness and high flexibility of CdS/CdTe structure, as well as on the monolithic integration possibility, many innovative applications of these devices become available. Among them, the direct integration of cadmium cell structure into new architectonic elements in order to realize the BIPV (Building Integrated Photovoltaics) concept at the elevated level [5] is one of the most challenging. To achieve this goal not only the proper technology must be applied, but also the internal cell structure has to be optimized and the general configuration, substrate choice and contacting problems should be considered. 2. Improvement of the material quality in ICSVT process The ICSVT (Isothermal Close Space Vapor Transport) technology has been widely announced as the efficient and robust method
∗ Corresponding author. Tel.: +48 42 631 26 43; fax: +48 42 636 80 24. ´ E-mail addresses: [email protected] (M. Sibinski), ˛ [email protected] (D. Sek). 0921-5107/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.mseb.2009.07.009
of CdS/CdTe heterostructure manufacturing [6,7]. Using this technique, the CdTe layers of 4–6 m grains have been achieved. High efficiency of the obtained cells suggested more complex processes than the simple structure modification. It was expected that it included the modification of material composition as well, and to check that, the investigations employing two independent analysis methods (BEC—Backscattered Electron Composition SEM spectrum analysis and X-ray spectroscopy) have been undertaken. The results presented in Table 1 and in Fig. 1 confirmed purification of the material during the ICSVT process. Sulphur (1.5%), which diffused from emitter region, is the only improper element present in the base layers. This may posses, however, some positive aspect of relaxing of the mechanical stress between emitter and base layers.
Table 1 CdTe base composition change, for the analogue manufacturing conditions for two fabrication methods, measured by means of X-ray spectroscopy. CdTe layer produced by standard screen-printing method
CdTe layer produced by ICSVT method
Element
Total content [%]
Element
Total content [%]
O Cl Cd Te S
10.93 1.94 43.15 43.98 –
O C Cd Te S
2.37 2.10 47.68 46.34 1.51
72
M. Sibi´ nski et al. / Materials Science and Engineering B 165 (2009) 71–73
Fig. 1. Improvement of ICSVT CdTe structure composition (b) referred to screen-printed and annealed CdTe layer (a) (X-ray diffraction analysis).
3. New applications of CdTe/CdS solar cells Taking the advantage of CdS/CdTe properties one can obtain a flexible and lightweight cell structure, a perfect choice for BIPV experiments. For practical realization of this construction, the analysis of all the possible cell configurations is necessary.
Thus the full set of possible device applications was prepared (Fig. 2). All proposed structures of novel CdS/CdTe devices, such as based on novel transparent polyketanil—dk0, were examined by means of practical experiments. Results were analysed by mechanical, optical and electrical measurements and confronted with numerical modelling outcomes. The specific research
Fig. 2. Possible CdTe solar cells configurations in BIPV applications.
M. Sibi´ nski et al. / Materials Science and Engineering B 165 (2009) 71–73
◦ ◦ ◦ ◦
73
verification of optical properties of chosen materials proposition of device configuration calculation of expected parameters of a new cell numerical simulation of proposed structure in SCAPS software
Employment of the investigated manufacturing technology allowed to obtain CdTe absorber layer based on polyimide layer, which is presented in Fig. 3. 4. Conclusions
Fig. 3. Example of CdTe absorber layer based on non-transparent polyimide foil.
scope, realized within the described investigations, is listed below. • BIPV cells in substrate configuration
◦ investigation and manufacturing of the cell on polymer nontransparent substrate ◦ designing and manufacturing of a cell on metal elastic foil ◦ designing and manufacturing of a cell on ceramic flat substrate ◦ adaptation of ICSVT method for application on non-flat ceramic substrates • BIPV cells in superstrate configuration ◦ review of transparent polymer substrates ◦ verification of thermal properties of chosen materials
The possibility of ICSVT technology implementation in BIPV was investigated. New, attractive features of this technique were reported and confirmed by means of SEM BEC analysis and X-ray spectroscopy as well. Possible configurations of CdS/CdTe cell in BIPV applications were discussed and practically verified. Results were evaluated by optical, mechanical and electrical measurements as well as numerical simulations. Acquired parameters confirmed manufacturability of a new cell construction. Acknowledgement The author is a scholarship holder of project entitled “Innovative education” supported by European Social Fund. References [1] C. Ferekides, D. Marinski, V. Viswanathan, Thin Solid Films 361–362 (2000) 520–526. [2] D. Bonett, Thin Solid Films 361–362 (2000) 547–552. [3] http://www.firstsolar.com. [4] T. Nisho, 25th Photovoltaic Specialists Conference, 1996, pp. 953–956. [5] A. Hunter, Photovoltaic Specialists Conference, 2002, pp. 1493–1496; M. Burgelman, Proc. of the 12th EPSEC Stephens & Associates, 1994, pp. 1554–1556. ´ [6] M. Sibinski, Microtherm 2000 Conference, 2000, pp. 53–60. [7] J. Goldstein, Scanning Electron Microscopy and X-ray microanalysis, Kluwer Academics, New York, 2003.
Contents lists available at ScienceDirect
Materials Science and Engineering B journal homepage: www.elsevier.com/locate/mseb
Novel construction of CdTe solar cell based on polyketanil structure a,∗ ´ ˛ b , Agnieszka Iwan b Maciej Sibinski , Zbigniew Lisik a , Danuta Sek a b
Department of Semiconductor and Optoelectronic Devices, Technical University of Łód´z, Poland Centre of Polymer and Carbon Materials, Polish Academy of Sciences, Zabrze, Poland
a r t i c l e
i n f o
Article history: Received 27 June 2008 Received in revised form 17 July 2009 Accepted 21 July 2009
a b s t r a c t A novel concept of CdS/CdTe solar cell structure utilisation for BIPV concept is reported. ICSVT as the base manufacturing technology is presented, in the background of its new properties investigation. Technological concepts of the cadmium telluride structure employment in its new application field are described. © 2009 Elsevier B.V. All rights reserved.
Keywords: Solar cell Thin film CdS/CdTe BIPV Polymer Polyimide
1. Introduction The classical CdS/CdTe solar cell structure is recognized as the very promising candidate for low-cost thin film solar modules [1,2]. Despite some production up-scaling problems these devices are at the level of the industrial manufacturing nowadays [3]. At this early stage, standardized CdS/CdTe modules production is mostly the aim of PV manufacturers, however, one should not forget cadmium telluride potential [4]. Based on the small thickness and high flexibility of CdS/CdTe structure, as well as on the monolithic integration possibility, many innovative applications of these devices become available. Among them, the direct integration of cadmium cell structure into new architectonic elements in order to realize the BIPV (Building Integrated Photovoltaics) concept at the elevated level [5] is one of the most challenging. To achieve this goal not only the proper technology must be applied, but also the internal cell structure has to be optimized and the general configuration, substrate choice and contacting problems should be considered. 2. Improvement of the material quality in ICSVT process The ICSVT (Isothermal Close Space Vapor Transport) technology has been widely announced as the efficient and robust method
∗ Corresponding author. Tel.: +48 42 631 26 43; fax: +48 42 636 80 24. ´ E-mail addresses: [email protected] (M. Sibinski), ˛ [email protected] (D. Sek). 0921-5107/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.mseb.2009.07.009
of CdS/CdTe heterostructure manufacturing [6,7]. Using this technique, the CdTe layers of 4–6 m grains have been achieved. High efficiency of the obtained cells suggested more complex processes than the simple structure modification. It was expected that it included the modification of material composition as well, and to check that, the investigations employing two independent analysis methods (BEC—Backscattered Electron Composition SEM spectrum analysis and X-ray spectroscopy) have been undertaken. The results presented in Table 1 and in Fig. 1 confirmed purification of the material during the ICSVT process. Sulphur (1.5%), which diffused from emitter region, is the only improper element present in the base layers. This may posses, however, some positive aspect of relaxing of the mechanical stress between emitter and base layers.
Table 1 CdTe base composition change, for the analogue manufacturing conditions for two fabrication methods, measured by means of X-ray spectroscopy. CdTe layer produced by standard screen-printing method
CdTe layer produced by ICSVT method
Element
Total content [%]
Element
Total content [%]
O Cl Cd Te S
10.93 1.94 43.15 43.98 –
O C Cd Te S
2.37 2.10 47.68 46.34 1.51
72
M. Sibi´ nski et al. / Materials Science and Engineering B 165 (2009) 71–73
Fig. 1. Improvement of ICSVT CdTe structure composition (b) referred to screen-printed and annealed CdTe layer (a) (X-ray diffraction analysis).
3. New applications of CdTe/CdS solar cells Taking the advantage of CdS/CdTe properties one can obtain a flexible and lightweight cell structure, a perfect choice for BIPV experiments. For practical realization of this construction, the analysis of all the possible cell configurations is necessary.
Thus the full set of possible device applications was prepared (Fig. 2). All proposed structures of novel CdS/CdTe devices, such as based on novel transparent polyketanil—dk0, were examined by means of practical experiments. Results were analysed by mechanical, optical and electrical measurements and confronted with numerical modelling outcomes. The specific research
Fig. 2. Possible CdTe solar cells configurations in BIPV applications.
M. Sibi´ nski et al. / Materials Science and Engineering B 165 (2009) 71–73
◦ ◦ ◦ ◦
73
verification of optical properties of chosen materials proposition of device configuration calculation of expected parameters of a new cell numerical simulation of proposed structure in SCAPS software
Employment of the investigated manufacturing technology allowed to obtain CdTe absorber layer based on polyimide layer, which is presented in Fig. 3. 4. Conclusions
Fig. 3. Example of CdTe absorber layer based on non-transparent polyimide foil.
scope, realized within the described investigations, is listed below. • BIPV cells in substrate configuration
◦ investigation and manufacturing of the cell on polymer nontransparent substrate ◦ designing and manufacturing of a cell on metal elastic foil ◦ designing and manufacturing of a cell on ceramic flat substrate ◦ adaptation of ICSVT method for application on non-flat ceramic substrates • BIPV cells in superstrate configuration ◦ review of transparent polymer substrates ◦ verification of thermal properties of chosen materials
The possibility of ICSVT technology implementation in BIPV was investigated. New, attractive features of this technique were reported and confirmed by means of SEM BEC analysis and X-ray spectroscopy as well. Possible configurations of CdS/CdTe cell in BIPV applications were discussed and practically verified. Results were evaluated by optical, mechanical and electrical measurements as well as numerical simulations. Acquired parameters confirmed manufacturability of a new cell construction. Acknowledgement The author is a scholarship holder of project entitled “Innovative education” supported by European Social Fund. References [1] C. Ferekides, D. Marinski, V. Viswanathan, Thin Solid Films 361–362 (2000) 520–526. [2] D. Bonett, Thin Solid Films 361–362 (2000) 547–552. [3] http://www.firstsolar.com. [4] T. Nisho, 25th Photovoltaic Specialists Conference, 1996, pp. 953–956. [5] A. Hunter, Photovoltaic Specialists Conference, 2002, pp. 1493–1496; M. Burgelman, Proc. of the 12th EPSEC Stephens & Associates, 1994, pp. 1554–1556. ´ [6] M. Sibinski, Microtherm 2000 Conference, 2000, pp. 53–60. [7] J. Goldstein, Scanning Electron Microscopy and X-ray microanalysis, Kluwer Academics, New York, 2003.