Modeling photocurrent action spectra of photovoltaic devices based on organic thin films

We have modeled experimental short-circuit photocurrent action spectra of poly(3-(4′-(1″,4″,7″-trioxaoctyl)phenyl)thiophene) (PEOPT)/fullerene (C60) thin film heterojunction photovoltaic devices. Modeling was based on the assumption that the photocurrent generation process is the result of the creation and diffusion of photogenerated species (excitons), which are dissociated by charge transfer at the PEOPT/C60 interface. The internal optical electric field distribution inside the devices was calculated with the use of complex indices of refraction and layer thickness of the materials as determined by spectroscopic ellipsometry. Contributions to the photocurrent from optical absorption in polymer and fullerene layers were both necessary to model the experimental photocurrent action spectra. We obtained values for the exciton diffusion range of 4.7 and 7.7 nm for PEOPT and C60, respectively. The calculated internal optical electric field distribution and resulting photocurrent action spectra were used in or...

[1]  K. Yoshino,et al.  Spectral Characteristics of C60-Conducting Polymer Junctions: Various Molecular D-A Type Photocells , 1994 .

[2]  Z. Knittl,et al.  Optics of Thin Films , 1977 .

[3]  Duncan W. McBranch,et al.  Charge-transfer range for photoexcitations in conjugated polymer/fullerene bilayers and blends , 1997 .

[4]  Gerald Earle Jellison,et al.  Data analysis for spectroscopic ellipsometry , 1993 .

[5]  R. H. Friend,et al.  Charge separation in localized and delocalized electronic states in polymeric semiconductors , 1998, Nature.

[6]  H. Nalwa.  Handbook of organic conductive molecules and polymers , 1997 .

[7]  P. Milani,et al.  Ellipsometric investigation of C60 single crystal , 1994 .

[8]  Mats Andersson,et al.  High Quantum Efficiency Polythiophene , 1998 .

[9]  R. Leblanc,et al.  Photovoltaic and electrical properties of Al/Langmuir-Blodgett films/Ag sandwich cells incorporating either chlorophyll a, chlorophyll b, or zinc porphyrin derivative , 1993 .

[10]  Mats Andersson,et al.  Laminated fabrication of polymeric photovoltaic diodes , 1998, Nature.

[11]  M. G. Harrison,et al.  Analysis of the photocurrent action spectra of MEH-PPV polymer photodiodes , 1997 .

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

[13]  R. Azzam,et al.  Ellipsometry and polarized light , 1977 .

[14]  David Braun,et al.  Semiconducting polymer‐buckminsterfullerene heterojunctions: Diodes, photodiodes, and photovoltaic cells , 1993 .

[15]  M. Andersson,et al.  Photodiode performance and nanostructure of polythiophene/C60 blends , 1997 .

[16]  Amal K. Ghosh,et al.  Merocyanine organic solar cells , 1978 .

[17]  R. Azzam,et al.  Ellipsometry and polarized light : North Holland, Amsterdam, 1987 (ISBN 0-444-87016-4). xvii + 539 pp. Price Dfl. 75.00. , 1987 .

[18]  Stephen C. Moratti,et al.  EXCITON DIFFUSION AND DISSOCIATION IN A POLY(P-PHENYLENEVINYLENE)/C60 HETEROJUNCTION PHOTOVOLTAIC CELL , 1996 .

[19]  A. M. Rao,et al.  Optical properties of C60 and related materials , 1996 .

[20]  Rice,et al.  Theory of photoinduced charge transfer in a molecularly doped conjugated polymer. , 1996, Physical review. B, Condensed matter.

[21]  Ching Wan Tang,et al.  Photovoltaic effects of metal–chlorophyll‐a–metal sandwich cells , 1975 .

[22]  H. B. Devore.  Spectral Distribution of Photoconductivity , 1956 .

[23]  Dielectric and optical properties of C60 material studied by ellipsometry and quantitative IR and UV/VIS spectroscopy , 1995 .

[24]  K. Yoshino,et al.  Organic photovoltaic cell with donor-acceptor double heterojunctions , 1996 .

[25]  Torsten Fritz,et al.  Computer Modelling of Organic Thin Film Solar Cells. I. Exciton Model of Photocurrent Generation , 1993 .