Effect of LiF/metal electrodes on the performance of plastic solar cells

The insertion of thin interlayers of LiF under the negative metal electrode (Al and Au) of bulk heterojunction solar cells significantly enhances the fill factor and stabilizes high open circuit voltages. Compared to devices without the LiF interfacial layer, the white light efficiencies increase by over 20% up to ηeff∼3.3%. Substitution of the LiF by another insulating interlayer SiOx results in lower overall efficiencies. In the case of a LiF/Au electrode, substantial efficiency enhancement is observed compared to a pristine Au electrode and white light efficiencies up to ηeff∼2.3% are reported.

[1]  H. Grubin.  The physics of semiconductor devices , 1979, IEEE Journal of Quantum Electronics.

[2]  D. P. Woodruff,et al.  Modern techniques of surface science , 1986 .

[3]  C. Tang,et al.  Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode , 1997 .

[4]  S. Shaheen,et al.  Highly efficient and bright organic electroluminescent devices with an aluminum cathode , 1997 .

[5]  Sokrates T. Pantelides,et al.  Charge transfer and dipole moments of polyatomic systems , 1997 .

[6]  S. Shaheen,et al.  Bright blue organic light-emitting diode with improved color purity using a LiF/Al cathode , 1998 .

[7]  Y. Ouchi,et al.  Electronic structure of Alq3/LiF/Al interfaces studied by UV photoemission , 1999 .

[8]  K. Seki,et al.  ENERGY LEVEL ALIGNMENT AND INTERFACIAL ELECTRONIC STRUCTURES AT ORGANIC/METAL AND ORGANIC/ORGANIC INTERFACES , 1999 .

[9]  Tae-Woo Lee,et al.  Evidence of band bending observed by electroabsorption studies in polymer light emitting device with ionomer/Al or LiF/Al cathode , 2000 .

[10]  Franco Cacialli,et al.  LiF/Al cathodes and the effect of LiF thickness on the device characteristics and built-in potential of polymer light-emitting diodes , 2000 .

[11]  C. Brabec,et al.  Origin of the Open Circuit Voltage of Plastic Solar Cells , 2001 .

[12]  D. Cahen,et al.  Fine Tuning of Au/SiO2/Si Diodes by Varying Interfacial Dipoles Using Molecular Monolayers , 2001 .

[13]  C. Brabec,et al.  2.5% efficient organic plastic solar cells , 2001 .