Design of nanostructures for photoelectric conversion using an organic vertical superlattice

Applied Physics Letters

Volumn 88, Issue 21, 2006, Pages

  Hiramoto, Masahiro ^a   Yamaga, Takumi ^a   Danno, Mari ^a   Suemori, Kouji ^a   Matsumura, Yoshio ^a   Yokoyama, Masaaki ^a  

^a OSAKA UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

NANOSTRUCTURED MATERIALS; OPTOELECTRONIC DEVICES; PHOTOELECTRICITY; SOLAR CELLS; THICKNESS CONTROL;

NANOSCOPIC STRUCTURES; ORGANIC SOLAR CELLS; ORGANIC VERTICAL SUPERLATTICE; SANDWICH-TYPE CELLS;

SUPERLATTICES;

EID: 33744511951     PISSN: 00036951     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.2206124     Document Type: Article

References (23)

1. H. Spanggaard and F. C. Krebs, Sol. Energy Mater. Sol. Cells 83, 125 (2004).
2. H. Hoppe and N. S. Sariciftci, J. Mater. Res. 19, 1924 (2004).
3. Organic Photovoltaics, Mechanisms, Materials, and Devices edited by, S.-S. Sun, and, N. S. Sariciftci, (CRC Press, New York, 2005).
4. C. W. Tang, Appl. Phys. Lett. 48, 183 (1986).
5. M. Hiramoto, H. Fujiwara, and M. Yokoyama, Appl. Phys. Lett. 58, 1062 (1991).
6. M. Hiramoto, H. Fujiwara, and M. Yokoyama, J. Appl. Phys. 72, 3781 (1992).
7. G. Yu, J. Gao, J. C. Hummelen, F. Wudl, and A. J. Heeger, Science 270, 1789 (1995).
8. J. Rostalski and D. Meissner, Sol. Energy Mater. Sol. Cells 61, 87 (2000).
9. S. E. Shaheen, C. J. Brabec, N. S. Sariciftci, F. Padinger, T. Fromherz, and J. C. Hummelen, Appl. Phys. Lett. 78, 841 (2001).
10. D. Gebeyehu, B. Maennig, J. Drechsel, K. Leo, and M. Pfeiffer, Sol. Energy Mater. Sol. Cells 79, 81 (2003).
11. P. Sullivan, S. Heutz, S. M. Schultes, and T. S. Jones, Appl. Phys. Lett. 84, 1210 (2004).
12. S. Uchida, J. Xue, B. P. Rand, and S. R. Forrest, Appl. Phys. Lett. 84, 4218 (2004).
13. M. Hiramoto, K. Suemori, and M. Yokoyama, Jpn. J. Appl. Phys., Part 1 41, 2763 (2002).
14. P. Peumans, S. Uchida, and S. R. Forrest, Nature (London) 425, 158 (2003).
15. K. Suemori, T. Miyata, M. Yokoyama, and M. Hiramoto, Appl. Phys. Lett. 86, 063509 (2005).
16. For precise estimation of the number of photons absorbed by the cross section of the OVSLs, the transmission of light in the transparent epoxy slice sandwiched between the Ag electrodes that causes lateral irradiation of the OVSLs should be eliminated. For this purpose, 200 nm thick H2 Pc and Me-PTC films were inserted at the respective interfaces between the exposed cross section and the Ag, i.e., the cell structure can be written as Ag H2 Pc (200 nm)OVSL (2 μm)Me-PTC (200 nm)Ag.
17. The bias direction was chosen to allow electrons and holes to move toward their respective Ag electrodes without energetic barriers, i.e., (+)AgMe-PTCOVSL H2 PcAg(-).
18. Since the dissociation of strongly bound Frenkel-type excitons occurs via charge transfer between Me-PTC and H2 Pc, direct molecular contacts at the Me-PTC H2 Pc heterointerface can be regarded as photocarrier generation sites.
19. For the very small values of x and y of less than 5 nm [Fig.], there is a possibility that the values of were affected by interlayer exciton transfer by a Förster mechanism.
20. Atomic force microscopic images revealed that Me-PTC: H2 Pc (1:1) films codeposited at room temperature have smooth and flat surfaces, and those codeposited at -170 °C consist of many nanoparticles of 20 nm diam surrounded by flat regions. The former showed no x-ray diffraction (XRD) peaks, and the latter only exhibited an XRD peak that was attributed to Me-PTC. Therefore, these were concluded to have the structures of a molecular mixture [Fig.] and a crystalline-amorphous nanocomposite [Fig.], respectively.
21. The shape of the absorption spectra for all of the Me-PTC H2 Pc superlattices including x=2.5 nm could be reproduced by the sum of those for single films of Me-PTC and H2 Pc. On the contrary, the shapes of the absorption spectra for codeposited films were distorted due to changes in the surrounding environments for the respective molecules. This strongly supports the notion that organic superlattices composed of even extremely thin films have a distinct layered structure.
22. M. Hiramoto, K. Hashimoto, and T. Sakata, Chem. Lett. 1990, 1343.
23. J. Takada, H. Awaji, M. Kinoshita, A. Nakajima, and W. A. Nevin, Appl. Phys. Lett. 61, 2184 (1992).