Merocyanine organic solar cells

Recently, we reported on the development of a new thin‐film organic solar cell with an AM1 sunlight efficiency of about 0.7% for large area devices (∼1 cm2). This relatively high‐efficiency MIS‐Schottky barrier‐type cell was based on merocyanine type photosensitizing dyes. In this paper we present additional experimental results and develop a comprehensive theoretical model to explain the observed photovoltaic properties. The model incorporates the generation, transport, and surface dissociation of excitons and field‐dependent quantum efficiency. The low fill factor of 0.3 was attributed mainly to the field dependence of quantum efficiency. An exciton diffusion length of 60 A was determined by analyzing the short‐circuit photocurrent action spectra using the theoretical model developed. The diffusion potentials for metal/merocyanine Schottky barrier cells for six different metals were determined by C‐V measurements; the diffusion potential increases with decreasing work function. As solar cells, these dev...

[1]  Amal K. Ghosh,et al.  Photovoltaic and rectification properties of Al/Mg phthalocyanine/Ag Schottky‐barrier cells , 1974 .

[2]  E. Yang,et al.  MIS‐Schottky theory under conditions of optical carrier generation in solar cells , 1976 .

[3]  C. Braun,et al.  Electric‐Field and Temperature Dependence of Photoconductivity , 1968 .

[4]  A. Ghosh,et al.  SnO2/Si solar cells—heterostructure or Schottky‐barrier or MIS‐type device , 1978 .

[5]  C. Tang,et al.  Transient photovoltaic effects in metal-chlorophyll-a-metal sandwich cells , 1975 .

[6]  Peter J. Melz,et al.  Photogeneration in Trinitrofluorenone-Poly(N-Vinylcarbazole) , 1972 .

[7]  H. Hovel,et al.  Organic solar cells of hydroxy squarylium , 1976 .

[8]  L. Onsager.  Deviations from Ohm's Law in Weak Electrolytes , 1934 .

[9]  L. Lyons,et al.  Photovoltages in tetracene films , 1971 .

[10]  R. Meek,et al.  Proceedings of the Third International Conference on Photoconductivity , 1971 .

[11]  J. Shewchun,et al.  Theory of metal‐insulator‐semiconductor solar cells , 1977 .

[12]  R. C. Enck,et al.  Onsager mechanism of photogeneration in amorphous selenium , 1975 .

[13]  S. Fonash.  The role of the interfacial layer in metal−semiconductor solar cells , 1975 .

[14]  Porphyrin films. 3. Photovoltaic properties of octaethylporphine and tetraphenylporphine , 1977 .

[15]  Amal K. Ghosh,et al.  High‐efficiency organic solar cells , 1978 .

[16]  A. Ghosh,et al.  Rectification, space‐charge‐limited current, photovoltaic and photoconductive properties of Al/tetracene/Au sandwich cell , 1973 .

[17]  M. Prince.  Silicon Solar Energy Converters , 1955 .

[18]  C. Braun,et al.  Intrinsic photoconduction in anthracene single crystals: Electric field dependence of hole and electron quantum yields , 1973 .

[19]  M. Pope,et al.  Photogeneration of Charge Carriers in Tetracene , 1966 .

[20]  H. Baessler,et al.  Dissociation of Frenkel Excitons at the Interface between a Molecular Crystal and a Metal , 1972 .

[21]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[22]  H. Baessler,et al.  Solution of the Onsager Ion Recombination Model in One Dimension , 1974 .