2017 Fiscal Year Annual Research Report
Highly Stable Carbon-sandwiched Perovskite Solar Cells
| Project/Area Number |
17H06609
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| Research Institution | The University of Tokyo |
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Principal Investigator |
田 日 東京大学, 大学院工学系研究科(工学部), 特任助教 (00807563)
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Keywords | 太陽電池 / ペロブスカイト太陽電池 / ナノカーボン材料 |
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| Outline of Annual Research Achievements |
The ultimate goal is to produce highly stable carbon allotropes-based PSCs. Success of this research will being a great impact to the society, and there are chiefly three aspects to this. As can be seen from the application from, the research plan was divided into different projects with letters A to D. Now in terms of progress we have achieved more than we expected and well ahead of the proposed research plan. We have already completed Project A and Project C. We have published 11 papers at this point from April 2017. Most of these papers are related to this JSPS Start-up Research as the JSPS grant number can be found in the Acknowledgement section. Now, we only have Project B and Project D left to complete the proposed research. As a continuation from year 2017 (last year), a hole-transporting ability of the low band-gap polymers will be investigated. Upon publication of this result, the same concept will be applied in the carbon-sandwiched architecture. Due to high viscosity and crystallinity of the low band-gap polymers, an effective polymer-carbon nanotube moisture barrier is predicted to be formed. Along with this, using carbon-sandwiched devices as the base architecture, low band-gap polymer and single-walled carbon nanotube nano-hybrid will be used as the top electrode. In this system, Li+@C60TFSI- will be added to function as both a dopant and an anti-oxidant, increasing efficiency and stability, respectively.
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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
According to the plan sheet we proposed in the application form, we are supposed to be finished with Project A and in the middle of Projects B and C. However, we are ahead of ourselves as Project A which is producing carbon-sandwiched structure of perovskite between C60 and carbon nanotubes. This work was collaboration with the Seoul National University and has already been completed and published in J. Mater. Chem. A [10.1039/c7ta09174e]. Also, Project C has also been completed and published in Angewandte Chemie International Edition and selected as the Very Important Paper [10.1002/anie.201800816.]. The remaining projects are Project B and Project D. For Project D, we have to wait for the completion of Project B, because Project D is about combining all of the Projects A, B, and C. For the project B, we have found 2 different kinds of low-band gap polymers, PNTz4T and PBTZT-stat-BDTT-8, and actively studying them. We discovered that PBTZT-stat-BDTT-8 is much more stable than P3HT and reported this in J. Mater. Chem. A [10.1039/c7ta11095b], but the performance when combined with MAPbI3 was not as great as we expected. This was due mainly to the fact that the absorption of PBTZT-stat-BDTT-8 did not go beyond 800 nm. As PNTz4T has longer wavelength absorption than PBTZT-stat-BDTT-8, we are expecting a much better result, which we will have to see.
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| Strategy for Future Research Activity |
As mentioned above, we will continue investigating PNTz4T as the hole-transporting material in perovskite solar cells. Also, we are planning to adopt a new technology of perovskite called 2D/3D perovskite for carbon nanotube electrode-applied perovskite solar cells. 3D/2D formamidinium lead iodide (FACsPbI3) photo-active can maximise the light absorption. In metal-electrode PSCs, the long-wavelengths of sunlight, which are not fully absorbed by the perovskite layer, get reflected by the metal electrode for further absorption. As carbon nanotube electrode are not reflective, the long- wavelength light is wasted in the case of carbon nanotube-based perovskite solar cells, resulting in low short-circuit current density. While maximising the light absorption by using low-band gap FAPbI3, is possible, FAPbI3 film has been reported to be extremely unstable. Therefore, we will harness a small amount of 2D perovskites to protect at the grain boundaries of FAPbI3 Adoption of this will strength our result of Project D, which is the ultimate goal of this project.
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