This title appears in the Scientific Report :
1999
Please use the identifier:
http://hdl.handle.net/2128/20457 in citations.
Optische und elektrische Untersuchungen nanokristalliner Halbleiter für photoelektrochemische Solarzellen
Optische und elektrische Untersuchungen nanokristalliner Halbleiter für photoelektrochemische Solarzellen
This work focuses on the optical and electrical properties of nanocrystalline Ti02 and PbS thin films. These materials show a tunable band gap, increasing with decreasing semiconductor particle size (quantum size effect). From electron microscopy pictures we can see, that the particle size and band...
Saved in:
Personal Name(s): | Antonius, C. |
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Contributing Institute: |
Institut für Festkörperforschung; IFF |
Imprint: |
Jülich
Forschungszentrum, Zentralbibliothek
1999
|
Dissertation Note: |
Nürnberg-Erlangen, Univ., Diss., 1999 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
ohne FE |
Series Title: |
Berichte des Forschungszentrums Jülich
3654 |
Subject (ZB): | |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
This work focuses on the optical and electrical properties of nanocrystalline Ti02 and PbS thin films. These materials show a tunable band gap, increasing with decreasing semiconductor particle size (quantum size effect). From electron microscopy pictures we can see, that the particle size and band edge increase with increasing temperature in the tempering process. Non-tempered Ti02, that was partly doped by noble metal salts, shows no detectable particle size and very low conductivity. It is assumed to be amorphous. The particle size of nanocrystalline PbS-layers varies between 3 and 10 nm and decreases with increasing content of Nation used as a stabilising agent. The photoelectric properties of these semiconductor layers were determined by electrochemically measuring photocurrent-spectra. Small particles show a hypsochromic shift of the spectrum but also very low photocurrents while noble metal salt doped Ti02 shows a bathochromic shift. An alternative to the liquid electrolyte in a photoelectrochemical sensibilisation cell is the use of a hole conducting liquid crystalline solid. In this cell a dye, which is adsorbed on the surface of a porous Ti02-electrode, injects electrons into the Ti02-electrode upon illumination while the holes are transported by the hole conductor to the back contact. Unfortunately the series resistance is still very high for this type of cell. The high resistance of 3 nm small PbS-particles was examined by temperature-dependent measurements. Accordingly, the conductivity for small particles can be described as an activated process with only one activation energy. This leads to the explanation that the low conductivity is a consequence of a low tunnel-probability between particles in the layer or a high "inner resistance" inside the particles. |