Tokyo Institute of Technology · Materials Science
Professor Yoichi Murakami's research lab specializes in the photophysical properties of low-dimensional nanomaterials, particularly single-walled carbon nanotubes (SWNTs), with a focus on their optical anisotropy, exciton dynamics, and photon upconversion mechanisms. The lab investigates fundamental processes such as exciton diffusion, annihilation, and triplet-triplet annihilation in SWNTs, aiming to understand and quantify exciton densities and optical cross sections under intense excitation. Additionally, the lab contributes to bioinformatics by developing computational tools like PSOPIA for predicting protein-protein interactions using network-based features, bridging nanomaterials science with systems biology. Their work spans from quantum-scale photophysics to applications in optoelectronics and biological network modeling.
Figures are computed from collected data and may differ slightly.
Freely available on the web at http://tardis.nibio.go.jp/PSIVER/
Anisotropic optical absorption properties of single-walled carbon nanotubes (SWNTs) are determined from a vertically aligned SWNT film for 0.5-6 eV. Absorption peaks at 4.5 and 5.25 eV are found to exhibit remarkable polarization dependence and have relevance to optical properties of graphite. A method for determining a nematic order parameter for an aligned SWNT film based on the collinear absorption peak at 4.5 eV is presented, followed by the determination of the optical absorption cross sect
This perspective article provides a comprehensive but organized tutorial introduction of the kinetics related to photon upconversion (UC) by triplet-triplet annihilation (TTA) (TTA-UC). The field of TTA-UC is multi-disciplinary and rapidly growing with the involvement of researchers from diverse backgrounds. TTA-UC consists of a series of tangled photophysical processes, so a solid understanding of the kinetic features and consequences is important to develop and evaluate materials for TTA-UC. T
Our results suggest that FNet, a feature representing proximity in a known PPI network between two proteins that are homologous to a target protein pair, contributes to the prediction of whether the target proteins interact or not. PSOPIA will help identify novel PPIs and estimate complete PPI networks. The method proposed in this article is freely available on the web at http://mizuguchilab.org/PSOPIA.
We have observed that photoemission from single-walled carbon nanotubes saturates in intensity as the excitation intensity increases. Each emission peak arising from specific-chirality tubes exhibited a saturation value independent of the excitation wavelength, suggesting an upper limit on the exciton density for each nanotube species. We developed a model based on diffusion-limited exciton-exciton annihilation, which allowed us to estimate exciton densities in the saturation regime. The estimat
http://www.bioinformatics.sussex.ac.uk/SHARP2.
The PiRaNhA web server is a publicly available online resource that automatically predicts the location of RNA-binding residues (RBRs) in protein sequences. The goal of functional annotation of sequences in the field of RNA binding is to provide predictions of high accuracy that require only small numbers of targeted mutations for verification. The PiRaNhA server uses a support vector machine (SVM), with position-specific scoring matrices, residue interface propensity, predicted residue accessib
We performed detailed photoluminescence (PL) spectroscopy studies of three different types of single-walled carbon nanotubes (SWNTs) by using samples that contain essentially only one chiral type of SWNT, (6,5), (7,5), or (10,5). The observed PL spectra unambiguously show the existence of an emission sideband at $\ensuremath{\sim}140\text{ }\text{meV}$ below the lowest singlet excitonic $({E}_{11})$ level, whose identity and origin are now under debate. We find that the energy separation between
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