Highly transparent solar cells｜Development of highly transparent solar cells using TMD
We have successfully developed highly transparent solar cells by transparentizing the electrodes of our proprietary Schottky-type TMD (Transition Metal Dichalcogenide) solar cells. Utilizing ITO (Indium Tin Oxide) as the transparent electrode and precisely controlling the Schottky barrier between ITO and TMD, we achieved clear solar power generation of 420 pW from a 1 cm² substrate. Moreover, the measured average visible light transmittance of this solar cell is 79%, demonstrating an exceptionally high level of transparency. This technology has the potential for widespread societal implementation, including energy harvesting from currently non-generating surfaces such as window glass and car windshields, and we are actively pursuing further research in this direction.
Scientific Reports, Vol. 12, No. 11315, pp. 1-8, 2022.7.4.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20220712_03web_tmd.pdf
Highly transparent solar cells｜Development of Schottky type solar cells with TMD
We are dedicated to developing transparent solar cells by maximizing the unique feature of TMDs, which are semiconductors at the atomic level. Initially, we focused on Schottky-type solar cells, which are easy to scale up. We conducted a demonstration of TMD Schottky solar cells, optimizing the electrode materials on both ends of the TMD. Through device design that separates functions, with one side facilitating charge separation with a high Schottky barrier and the other side serving as a low Schottky barrier for current collection, we achieved the highest overall power generation efficiency (0.7%) for TMD solar cells with a few layers or less.
Scientific Reports, Vol. 7, No. 11967, pp. 1-10, 2017.9.20.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20170919_02web.pdf
Quantum Devices｜Integration Synthesis of Graphene Nanoribbon Quantum Dot Devices
We have demonstrated that by shortening the length of graphene nanoribbons synthesized using our method to the utmost limit, they behave as graphene nanoribbon quantum dots. This is a result of collaborative research with Professor Otsuka of Tohoku University, among others. The achievement demonstrates that well-defined levels and excited states in quantum dots can be observed up to relatively high temperatures, verifying the functionality of our integratable graphene quantum dot devices as effective quantum dots. We plan to further apply this technology to practical quantum integrated devices in the future.
Communications Materials, Vol. 3, No. 103, pp. 1-7, 2022.12.22.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20230106_01web_graphene.pdf
Fusion of AI and Materials Synthesis｜High-Efficiency Exploration of Carbon Nanotube Synthesis Catalysts
We believe that the design of catalyst nanoparticles is a crucial factor in controlling the chirality of carbon nanotubes. In this study, we are leveraging machine learning to explore unknown catalysts that may lead to chirality control.
TMD｜Development of High-Transparency Solar Cells Using TMD
We have successfully developed high-transparency solar cells by making the electrodes of our proprietary Schottky-type TMD solar cells transparent. Using ITO as a transparent electrode and precisely controlling the Schottky barrier between ITO and TMD, we achieved clear solar power generation from a 1 cm² substrate, generating 420 pW. Additionally, the measured visible light average transmittance of this solar cell was found to be 79%, demonstrating an extremely transparent solar cell. This technology has the potential for widespread application, allowing energy extraction from surfaces such as window glass or car windshields, which currently do not generate any power. We are actively advancing research for practical implementation in society.
Scientific Reports, Vol. 12, No. 11315, pp. 1-8, 2022.7.4.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20220712_03web_tmd.pdf
TMD｜TDevelopment of Schottky type solar cells with TMD
We are leveraging the atomic-level thin semiconductor characteristics of Transition Metal Dichalcogenides (TMDs) to develop transparent solar cells. Initially focusing on Schottky-type solar cells due to their ease of large-scale production, we conducted a demonstration of TMD Schottky solar cells. By optimizing the electrode materials at both ends of the TMD, we designed the device to function with a high Schottky barrier for charge separation and a low Schottky barrier for current collection. This innovative design led to the achievement of the highest overall power conversion efficiency (0.7%) for TMD solar cells with a few layers or less.
Scientific Reports, Vol. 7, No. 11967, pp. 1-10, 2017.9.20.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20170919_02web.pdf
TMD｜Fabrication of Janus TMD
We refer to Transition Metal Dichalcogenides (TMDs) where the upper and lower surfaces are composed of different chalcogen atoms as Janus TMDs. Due to the difficulty in synthesizing these materials, there has been limited progress in experimental research. However, our research group has achieved the creation of high-quality Janus TMDs. Currently, our focus is on understanding the reaction processes of Janus TMDs, improving their quality, and exploring applications in devices. Recent collaborative efforts involve the utilization of Janus TMDs, such as creating Janus TMD nanotubes and Janus TMD nanoscrolls, introducing novel structural materials. We are also engaged in various collaborative research projects, and this area holds promising prospects for future developments.
https://www.wpi-aimr.tohoku.ac.jp/jp/achievements/press/2023/20231006_001683.html
TMD｜Non-Classical Nucleation Mechanism of TMD Revealed by In-Situ Observations
By leveraging our independently developed in-situ observation CVD (Chemical Vapor Deposition) method, we have, for the first time, revealed that the nucleation of Transition Metal Dichalcogenides (TMDs) follows a non-classical two-stage process. This fundamental research into the crystal growth of TMDs, elucidated through crystallography, is crucial for addressing issues such as defect control and improving the quality, which will be essential for enhancing device performance in the future.
Scientific Reports, Vol. 11, No. 22285, pp. 1-9, 2021.11.15.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20211115_02web_tmd.pdf
TMD｜Development of “In-Situ Monitoring Synthesis” for TMD
We achieved the world’s first direct optical observation of the synthesis process of 2D crystals, specifically Transition Metal Dichalcogenides (TMDs) with atomic thickness. This groundbreaking success allowed us to reveal that the liquid droplet precursor diffuses over an impressive distance of 750 micrometers. This is a crucial advancement contributing to a detailed understanding of the synthesis mechanism of TMDs.
Scientific Reports, Vol. 9, No. 12958, pp. 1-7, 2019.9.10.
https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20190909_03web_handotai.pdf
TMD｜Understanding the Exciton Diffusion Behavior in TMD
We experimentally demonstrated that excitons in Transition Metal Dichalcogenides (TMDs) can undergo long-range diffusion over several micrometers. Furthermore, our study suggests a clear distinction in the diffusion processes between neutral excitons and trions.
ACS Nano, Vol. 10, No. 10, pp. 9687-9694, 2016.9.24.
TMD｜Direct Observation of Localized Excitons in TMD
We have discovered the emergence of sharp emission spectra within defective Transition Metal Dichalcogenides (TMDs), and demonstrated that these are attributed to defect-captured localized excitons.
ACS Nano,Vol. 8, No. 12, pp. 12777-12785, 2014.12.3.
