2019 Fiscal Year Research-status Report
Research and development of new type photo-devices using compound semiconductors
| Project/Area Number |
19K15029
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
カトリ イゾール 東京理科大学, 研究推進機構総合研究院, 助教 (50562740)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | Compound semicondutor / Metastable behaviors / Alkali-metal / Photo-devices / Stability / Electron Irradiation / Proton Irradiation / High-efficiency |
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| Outline of Annual Research Achievements |
Metastable behavior of cesium fluoride (CsF) treated CIGS solar cells is investigated via heat-light soaking (HLS) and subsequent heat-soaking (HS) treatments. HLS treatment increases the net carrier concentration, open-circuit voltage, fill factor, and decreases short-circuit current density, whereas HS acts oppositely. It is found that metastable behavior originates from Cs-containing compounds and/or the migration of alkali metals at the surface and bulk regions.
Furthermore, the metastable behavior and/or degradation properties of CsF-treated CIGS solar cells are evaluated under electron and proton irradiation. These studies confirm the possibility of long-term applications of CsF-treated CIGS solar cells in terrestrial and space.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
By controlling the metastable behavior in CsF-treated CIGS solar cells, high-efficiency solar cells (above 19.4%) were fabricated. Additionally, in the very first time, the metastable behavior and/or degradation properties of CsF-treated CIGS solar cells were evaluated under electron and proton irradiation. It is well known that stress environments influence the metastable behavior of solar cells. From a scientific and commercial viewpoint, these studies are necessary to understand the stability issue of alkali-treated CIGS solar cells. It is understood that CsF-treated CIGS solar cells are robust to electron and proton environments and show the possibility for long-term commercial applications in terrestrial and space.
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| Strategy for Future Research Activity |
Next, many samples of different bandgaps will be fabricated, and their defects properties will be analyzed. Admittance spectroscopy, temperature-dependent current-voltage, capacitance-voltage, the electrochemical impedance will be used to characterize the devices. Additionally, we will not only limit our studies on CsF treatment. A wide range of alkali metals will be used and investigated.
The motivation will be to understand the defect physics of heavy alkali metal incorporated CIGS solar cells. New properties on alkali-treated chalcogenide materials will be explored to broaden its application fields.
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