| AVS 58th Annual International Symposium and Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Thursday Sessions |
| Session EL+AS+EM+MS+PS+TF-ThM |
| Session: | Spectroscopic Ellipsometry of Biological Materials and Organic Films |
| Presenter: | L. Kitzinger, SEMILAB-SOPRALAB, France |
| Authors: | J.P. Piel, SEMILAB-SOPRALAB, France L. Kitzinger, SEMILAB-SOPRALAB, France A. Bondaz, SEMILAB-SOPRALAB, France C. Defranoux, SEMILAB-SOPRALAB, France |
| Correspondent: | Click to Email |
Spectroscopic Ellipsometry (S.E) is a well known optical technique widely used for the characterisation of all types of thin films for determination of film thickness and optical indices on glass or plastic substrates.
S.E. is also being applied to the characterization of materials and multilayer structures of organic materials like organic light-emitting diodes (OLEDs) or Organic Solar Cells.
We present the determination of the refractive indices of organic Solar Cells materials like P3HT, PCBM, Pentacene, Perylene, and their blends. Complex organic materials can be analyzed accurately and fully characterized from their absorption bands in the visible and UV range (190nm to 900nm).
Transmission and absorption can be also measured at the same time and be used to determine the optical properties of these materials.
Using these refractive indices, analysis of real multi-layer stacks can be done. The refractive indices can be used afterwards to automatically optimise and balance the energy flow dissipation Q inside an organic solar cell composed of a thin film stack. We present an example performed on a single cell and on a tandem bi-layer cell structure.
Since these materials are sensitive to moisture and pollution, it can be necessary to measure their optical properties and thickness values through an encapsulated media. We will demonstrate how we can measure single layer properties and multi-layer stacks, through encapsulated samples, from the back side of the substrate. This technique can be applied to test structure or real Organic Solar Cell monitoring. Backside measurement combined with a water vapour cell used for ellipsometry porosimetry is used to test the efficiency of the thin film encapsulation.
We also present the characterization of ITO and ZnO transparent electrodes by S.E. and how near infra-red ellipsometry is used to determine the ITO resistance, without contact, by using the Drude behaviour on encapsulated samples.