Polaron absorption for photovoltaic energy conversion in a manganite-titanatepnheterojunction
| Autor: | Dong Su, Yimei Zhu, Jonas Norpoth, Christian Jooss, Gesine Saucke |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Materials science
Condensed matter physics Absorption spectroscopy Heterojunction 02 engineering and technology Photovoltaic effect Polaron absorption photovoltaic energy conversion manganite-titanate heterojunction 021001 nanoscience & nanotechnology Condensed Matter Physics Polaron Manganite 01 natural sciences 7. Clean energy Electronic Optical and Magnetic Materials Excited state 0103 physical sciences Absorption (logic) 010306 general physics 0210 nano-technology Perovskite (structure) |
| Zdroj: | Physical Review B. 85 |
| ISSN: | 1550-235X 1098-0121 |
| Popis: | The relation among structure, electric transport, and photovoltaic effect is investigated for a $\mathrm{pn}$ heterojunction with strong correlation interactions. A perovskite interface is chosen as a model system consisting of the $p$-doped strongly correlated manganite ${\mathrm{Pr}}_{0.64}{\mathrm{Ca}}_{0.36}{\mathrm{MnO}}_{3}$ (PCMO) and the $n$-doped titanate SrTi${}_{1\ensuremath{-}y}$Nb${}_{y}$O${}_{3}$ ($y=0.002$ and 0.01). High-resolution electron microscopy and spectroscopy reveal a nearly dislocation-free, epitaxial interface and give insight into the local atomic and electronic structure. The presence of a photovoltaic effect under visible light at room temperature suggests the existence of mobile excited polarons within the band-gap-free PCMO absorber. The temperature-dependent rectifying current-voltage characteristics prove to be mainly determined by the presence of an interfacial energy spike in the conduction band and are affected by the colossal electroresistance effect. From the comparison of photocurrents and spatiotemporal distributions of photogenerated carriers (deduced from optical absorption spectroscopy), we discuss the range of the excited polaron diffusion length. |
| Databáze: | OpenAIRE |
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