Premium
Phenoxazine Dyes for Dye‐Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime
Author(s) -
Karlsson Karl Martin,
Jiang Xiao,
Eriksson Susanna K,
Gabrielsson Erik,
Rensmo Håkan,
Hagfeldt Anders,
Sun Licheng
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201003730
Subject(s) - phenoxazine , dye sensitized solar cell , electron , chemistry , materials science , photochemistry , optoelectronics , biophysics , medicine , physics , biology , pharmacology , phenothiazine , electrode , electrolyte , quantum mechanics
A series of metal‐free organic dyes with a core phenoxazine chromophore have been synthesized and tested as sensitizers in dye‐sensitized solar cells. Overall conversion efficiencies of 6.03–7.40 % were reached under standard AM 1.5G illumination at a light intensity of 100 mW cm −2 . A clear trend in electron lifetime could be seen; a dye with a furan‐conjugated linker showed a shorter lifetime relative to dyes with the acceptor group directly attached to the phenoxazine. The addition of an extra donor unit, which bore insulating alkoxyl chains, in the 7‐position of the phenoxazine could increase the lifetime even further and, together with additives in the electrolyte to raise the conduction band, an open circuit voltage of 800 mV could be achieved. From photoelectron spectroscopy and X‐ray absorption spectroscopy of the dyes adsorbed on TiO 2 particles, it can be concluded that the excitation is mainly of cyano character (i.e., on average, the dye molecules are standing on, and pointing out, from the surface of TiO 2 particles).