Quantification of the Effects of Recombination and Injection in the Performance of Dye-Sensitized Solar Cells Based on N-Substituted Carbazole Dyes


Barea E. M. , ZAFER C., GÜLTEKİN B., Aydin B., KOYUNCU S. , Icli S., ...Daha Fazla

JOURNAL OF PHYSICAL CHEMISTRY C, cilt.114, ss.19840-19848, 2010 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 114 Konu: 46
  • Basım Tarihi: 2010
  • Doi Numarası: 10.1021/jp1055842
  • Dergi Adı: JOURNAL OF PHYSICAL CHEMISTRY C
  • Sayfa Sayıları: ss.19840-19848

Özet

Two new sensitizers for dye sensitized solar cells have been designed consisting of thiophene units asymmetrically functionalized by N-aryl carbazole. The di(tert-butyl) carbazole moieties acts as an electron donor group, the thiophene chain as a bridge group, and the cyanoacrylic acid as an anchoring and electron acceptor group. An increase of the conjugation length produces two main effects: first, it leads to a red-shift of the optical absorption of the dyes, resulting in an improved overlap of the absorption with the solar spectrum. Second, the oxidation potential decreases. The photovoltaic performance of this set of dyes as sensitizers in mesoporous TiO2 solar cells was investigated using electrolytes containing the iodide/triiodide redox couple. The dye with the best absorption characteristics showed the highest photocurrent but lower open circuit voltage due to more losses by recombination. A trend between structure (molecule dyes size) and recombination is demostrated using an analysis procedure based on beta-recombination model that combines impedance spectroscopy and density current-voltage data.