Article
Chemistry, Multidisciplinary
Dipti Jasrasaria, Eran Rabani
Summary: This study developed an atomistic approach for describing exciton-phonon coupling in semiconductor nanocrystals and validated the method's reliability. Experimental results showed that exciton-phonon coupling leads to lattice distortion in nanocrystals, with surface modes playing a significant role in smaller nanocrystals and interior modes dominating in larger systems.
Article
Chemistry, Multidisciplinary
Marcell Palmai, Joseph S. Beckwith, Nyssa T. Emerson, Tian Zhao, Eun Byoel Kim, Shuhui Yin, Prakash Parajuli, Kyle Tomczak, Kai Wang, Bibash Sapkota, Ming Tien, Nan Jiang, Robert F. Klie, Haw Yang, Preston T. Snee
Summary: Semiconductor quantum dots play a significant role in studying biological interactions and alternative energy applications due to their tunable optoelectronic properties. Besides the size-dependent quantum confinement effects, other mechanisms of electronic structural control are also being investigated. This study introduces a new structure-property concept that spatially localizes electrons or holes within a core/shell heterostructure by tuning the charge carrier's kinetic energy. This enables extended radiative lifetimes and continuous emission at the single-nanoparticle level, leading to new applications in optics and the development of advanced materials.
Article
Chemistry, Multidisciplinary
Chun Zhou, Joao M. Pina, Tong Zhu, Darshan H. Parmar, Hao Chang, Jie Yu, Fanglong Yuan, Golam Bappi, Yi Hou, Xiaopeng Zheng, Jehad Abed, Hao Chen, Jian Zhang, Yuan Gao, Bin Chen, Ya-Kun Wang, Haijie Chen, Tianju Zhang, Sjoerd Hoogland, Makhsud Saidaminov, Liaoxin Sun, Osman M. Bakr, Hongxing Dong, Long Zhang, Edward H. Sargent
Summary: In this study, Perovskite quantum dots superlattices were successfully self-assembled with the assistance of sodium as assembly director, forming ordered three-dimensional structures with increased attraction and decreased inter-dot distance. These structures facilitate exciton delocalization and sustained nanosecond lasing operation with a threshold of 25 mu J cm(-2).
Article
Chemistry, Physical
Go Yumoto, Yoshihiko Kanemitsu
Summary: Lead halide perovskite nanocrystals have gained considerable attention as next-generation optoelectronic materials. This article summarizes recent advances in the photophysics of excitons and biexcitons in these nanocrystals. Understanding their dynamics is crucial for optimal design of optoelectronic devices and the development of new functional properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Carolina Villamil Franco, Benoit Mahler, Christian Cornaggia, Thomas Gustavsson, Elsa Cassette
Summary: Understanding multiple exciton interactions and dynamics in semiconductor nanostructures is crucial for their use in light convertors. Investigations on 2D lead iodide perovskite nanoplatelets showed that nonradiative Auger recombination is the dominant pathway for multiexciton recombination, with dynamics subquadratic with exciton density. High excitation fluence leads to faster recombination rates.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Wei Fu, Jiefu Yin, Huaqiang Cao, Zhongfu Zhou, Junying Zhang, Jingjing Fu, Jamie H. Warner, Cheng Wang, Xiaofang Jia, G. Neville Greaves, Anthony K. Cheetham
Summary: The photoluminescence blinking behavior of single quantum dots under steady illumination is a significant yet controversial topic. It hinders the use of single quantum dots in bioimaging. Different mechanisms, particularly the non-radiative Auger recombination mechanism, have been proposed to explain it. Fluorescence non-blinking is observed in photocharged single graphene quantum dots (GQDs) due to the presence of singly charged trions that maintain photon emission through radiative and non-radiative Auger recombination. This phenomenon is attributed to the different energy levels caused by oxygen-containing functional groups in the GQDs, and the suppression of blinking is attributed to trap site filling caused by Coulomb blockade.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Ziyi Hu, Ben Breeze, Reza J. Kashtiban, Jeremy Sloan, James Lloyd-Hughes
Summary: This study investigated the impact of HgTe NWs synthesized inside SWCNTs on their optical and electronic properties. The results showed that the influence varied with the chirality of the SWCNTs. For semiconducting SWCNTs, HgTe NWs suppressed Auger relaxation processes and enhanced photoluminescence. On the other hand, HgTe NWs increased the Auger relaxation rate and phonon relaxation of metallic SWCNTs, boosting electronic transport.
Article
Materials Science, Multidisciplinary
Taofang Zeng, Yi He
Summary: The study establishes a computationally executable approach for modeling electron-phonon and exciton-phonon interaction in semiconductor nanoclusters. It reveals the significance of single-phonon and multiple-phonon nonradiative relaxation for electrons and excitons in nanocrystals. Nonradiative relaxation rates in Si(46) are consistent with experimental results reported for similar nanocrystals.
Article
Multidisciplinary Sciences
Zikang Ye, Xing Lin, Na Wang, Jianhai Zhou, Meiyi Zhu, Haiyan Qin, Xiaogang Peng
Summary: Phonon-assisted up-conversion photoluminescence boosts energy by absorbing vibration energy, and colloidal quantum dots can be used as efficient, stable, and cost-effective emitters for up-conversion photoluminescence.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Yingying Li, Peisen Zhang, Wen Tang, Kevin J. McHugh, Stephen V. Kershaw, Mingxia Jiao, Xiaodan Huang, Sergii Kalytchuk, Collin F. Perkinson, Saisai Yue, Yuanyuan Qiao, Lichong Zhu, Lihong Jing, Mingyuan Gao, Buxing Han
Summary: This study develops CuInSe2@ZnS:Mn quantum dots with intrinsic multifunctionality, which can accurately localize small metastases and act as potent tumor ablation agents.
Article
Chemistry, Multidisciplinary
Nima Taghipour, Mariona Dalmases, Guy L. Whitworth, Miguel Dosil, Andreas Othonos, Sotirios Christodoulou, Shanti Maria Liga, Gerasimos Konstantatos
Summary: This study utilizes PbS/PbSSe core/alloyed-shell colloidal quantum dots (CQDs) as a gain medium for infrared laser devices. The researchers achieved highly suppressed Auger recombination and lower amplified spontaneous emission (ASE) threshold by doping these engineered CQDs and successfully achieved near-infrared laser emission.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
A. Kamboj, L. Nordin, P. Petluru, A. J. Muhowski, D. N. Woolf, D. Wasserman
Summary: This study demonstrates all-epitaxial guided-mode resonance mid-wave infrared type-II superlattice nBn photodetectors, showing polarization- and angle-dependent detector response with strongly enhanced absorption. The detectors exhibit high operating temperature external quantum efficiencies over 50% at 200K for TE-polarized light with a thin absorber layer. The calculated specific detectivity on resonance at T = 200K is comparable with state-of-the-art MWIR detectors.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Gang Qiang, Aleksandr A. Golovatenko, Elena V. Shornikova, Dmitri R. Yakovlev, Anna V. Rodina, Evgeny A. Zhukov, Ina V. Kalitukha, Victor F. Sapega, Vadim Kh. Kaibyshev, Mikhail A. Prosnikov, Peter C. M. Christianen, Aleksei A. Onushchenko, Manfred Bayer
Summary: Exciton recombination dynamics and spin polarization in CdSe nanocrystals synthesized in a glass matrix were investigated using polarized photoluminescence in high magnetic fields up to 30 Tesla. The study revealed that the dynamics are accelerated by increasing temperature and magnetic field, and circularly polarized photoluminescence in magnetic fields showed several unusual appearances. The observed features were explained by a theoretical model, highlighting the competition between different recombination channels and the inhomogeneous broadening of the photoluminescence spectrum from the ensemble of nanocrystals.
Article
Chemistry, Multidisciplinary
Nima Taghipour, Guy L. Whitworth, Andreas Othonos, Mariona Dalmases, Santanu Pradhan, Yongjie Wang, Gaurav Kumar, Gerasimos Konstantatos
Summary: A binary blend of CQDs and ZnO nanocrystals is used to passivate trap states in PbS-CQD gain medium, leading to improved Auger lifetime and suppression of trap-assisted Auger recombination. Integration of this binary blend with a DFB resonator has demonstrated stable single-mode lasing emission with low threshold and continuous operation of 5 hours under room temperature and ambient conditions.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Physical
Shawn Irgen-Gioro, Yue Wu, Rafael Lopez-Arteaga, Suyog Padgaonkar, Jack N. Olding, Emily A. Weiss
Summary: This study investigates the emission characteristics of CdSe/CdS core/shell nanplatelets and finds that blinking primarily occurs on time scales from 100 ps to seconds, while spectral diffusion mainly occurs on time scales of approximately 1 second and slower. Shorter time scale blinking is attributed to an equilibrium between dark and bright states, while longer time scale blinking involves an equilibrium between two distinct emissive states.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Yulian Han, Morihiko Hamada, I-Ya Chang, Kim Hyeon-Deuk, Yasuhiro Kobori, Yoichi Kobayashi
Summary: This study reports on the durable and temperature-independent T-type photochromism of colloidal Cu-doped ZnS nanocrystals. The color changes efficiently under UV light irradiation, with rapid decoloration in solutions. The research highlights the importance of excited carrier dynamics and trap depths for various advanced photofunctional materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Yasuki Kawanishi, Katsuya Mutoh, Jiro Abe, Yoichi Kobayashi
Summary: Novel fast photochromic PTIC derivatives were developed, forming charge transfer states and neutral open-shell transient species upon light irradiation. Extending the lifetimes of CT states through substitution altered their optical properties and chemical reactivities. Developing fast T-type photochromic molecules generating long-lived CT forms is crucial for expanding applications of fast photoswitching materials.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Atsuko Kuno, Goki Hirata, Hiroki Tanaka, Yoichi Kobayashi, Nobuhiro Yasuda, Hiromitsu Maeda
Summary: A series of anion-responsive pi-electronic molecules containing phenylpyridine ligands were synthesized in this study, showing phosphorescence emission with high quantum yields and solution-state anion binding. These molecules exhibited solid-state ion-pairing assemblies with various binding modes, influenced by the substituents and geometries/electronic states of their countercations.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Shutaro Yamaoka, I-Ya Chang, Kim Hyeon-Deuk
Summary: In this study, the behavior of hydrogen molecules in non-equilibrium flow through a carbon nanotube was investigated using quantum molecular dynamics. The study found that non-equilibrium flow leads to increased condensation and accelerated adsorption of hydrogen molecules near the surface of the nanotube, resulting in smoother molecular flow.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Materials Science, Multidisciplinary
TaeGi Lee, Kazuma Ohshiro, Taichi Watanabe, Kim Hyeon-Deuk, DaeGwi Kim
Summary: The formation of minibands in quantum dot superlattices increases the mobility of carriers, offering a new approach for optoelectronic devices. This study investigates the temperature dependence of photoluminescence properties in CdTe quantum dot superlattices, revealing that the Stokes shift decreases and the decay time of miniband edge photoluminescence increases with temperature.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Yuki Watanabe, Kim Hyeon-Deuk, Takafumi Yamamoto, Masayoshi Yabuuchi, Olesia M. Karakulina, Yasuto Noda, Takuya Kurihara, I-Ya Chang, Masanobu Higashi, Osamu Tomita, Cedric Tassel, Daichi Kato, Jingxin Xia, Tatsuhiko Goto, Craig M. Brown, Yuto Shimoyama, Naoki Ogiwara, Joke Hadermann, Artem M. Abakumov, Sayaka Uchida, Ryu Abe, Hiroshi Kageyama
Summary: The success and continued expansion of research on metal-oxo clusters is attributed to their rich structures and wide range of functions. However, most known metal-oxo clusters are negatively charged polyoxometalates, with only a few cationic and functional ones. This study presents an all-inorganic hydroxyiodide with a unique structure and function as an excellent solid acid catalyst.
Article
Chemistry, Physical
I-Ya Chang, Shutaro Yamaoka, Kim Hyeon-Deuk
Summary: The condensation of H-2 and D-2 molecules in a carbon nano tube (CNT) and their flow through nano pores offer a key test to study mass molecular transport and separation of purely isotopic molecules. The enhanced nuclear quantum effects (NQEs) of the different mass molecules influence their behavior in the nanoscale CNT. The insights gained from this study can help in the design of nanoporous materials for adsorptive separation of condensed-phase mixtures under a nonequilibrium flow.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Kim Hyeon-Deuk, I-Ya Chang
Summary: This research developed a new non-empirical quantum molecular dynamics method to simulate real-time dynamics of hydrogen molecules satisfying the nuclear spin statistics. Through experiments and simulations, it was found that the nuclear quantum rotation of hydrogen molecules can cause differences in dynamics and reactions among different species of hydrogen.
COMMUNICATIONS CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Daisuke Yoshioka, Yusuke Yoneda, I-Ya Chang, Hikaru Kuramochi, Kim Hyeon-Deuk, Yoichi Kobayashi
Summary: Organic-inorganic nanohybrids using semiconductor nanocrystals coordinated with aromatic organic molecules have been extensively studied in optoelectronic materials. This study demonstrates the reversible displacement of coordination bonds between ligand molecules and zinc sulfide nanocrystals by light irradiation. Time-resolved spectroscopy and density functional theory calculations reveal that the displacement is driven by ultrafast hole transfer and the surviving radical anion of the ligand. These photoinduced ligand displacements have implications for the development of advanced photofunctional materials.
Article
Nanoscience & Nanotechnology
I-Ya Chang, Kim Hyeon-Deuk
Summary: External pressure plays a crucial role in understanding the photoproperties of nanomaterials. In this study, we computationally investigate the effects of external pressure on a silicon vacancy diamond nanoslab, including its structures, orbitals, photoproperties, and vibrational dynamics. By mechanically compressing the nanoslab, we observe significant changes in the defect structures, orbital energies, optical transition, orbital hybridization, and spectral properties. The energy of absorption, emission, and zero-phonon line show non-monotonic behavior with a maximum at below 7% compression. These findings provide insights into the control of split-vacancy centers as promising single-photon sources for nanoscale optical measurements of temperature and pressure in compressed nanomaterials.
ACS APPLIED NANO MATERIALS
(2023)
Article
Multidisciplinary Sciences
Akira Yokoi, Mayu Ukai, Takao Yasui, Yasuhide Inokuma, Kim Hyeon-Deuk, Juntaro Matsuzaki, Kosuke Yoshida, Masami Kitagawa, Kunanon Chattrairat, Mikiko Iida, Taisuke Shimada, Yumehiro Manabe, I-Ya Chang, Eri Asano-Inami, Yoshihiro Koya, Akihiro Nawa, Kae Nakamura, Tohru Kiyono, Tomoyasu Kato, Akihiko Hirakawa, Yusuke Yoshioka, Takahiro Ochiya, Takeshi Hasegawa, Yoshinobu Baba, Yusuke Yamamoto, Hiroaki Kajiyama
Summary: Cancer cell-derived extracellular vesicles (EVs) could be potential targets for disease biomarkers due to their unique protein profiles. Analysis of small EVs (sEVs) and medium/large EVs (m/lEVs) revealed that both subtypes had distinct proteomic characteristics. Specific sEV proteins (FRa, Claudin-3, and TACSTD2) for high-grade serous ovarian carcinoma (HGSOC) were identified, while no candidates were found for m/lEVs. Additionally, a microfluidic device using polyketone-coated nanowires (pNWs) was developed for efficient sEV isolation and showed specific detectability in cancer patients and predicted clinical status.
Article
Chemistry, Physical
Shutaro Yamaoka, Kim Hyeon-Deuk
Summary: This study used non-empirical ab initio molecular dynamics method to investigate supercritical hydrogen, revealing strong nuclear quantum effects and anomalous order changes along density variations. It was shown that deviations between liquid-like and gas-like solvations around the Widom line lead to heterogeneity in the supercritical fluid, serving as an index to monitor supercriticality and identify distinct liquid-like and gas-like regions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Yoshifumi Sasano, Hiroki Tanaka, Yohei Haketa, Yoichi Kobayashi, Yukihide Ishibashi, Tatsuki Morimoto, Ryuma Sato, Yasuteru Shigeta, Nobuhiro Yasuda, Tsuyoshi Asahi, Hiromitsu Maeda
Summary: Charged pi-electronic species were observed to develop stacking structures based on electrostatic and dispersion forces, with the concept of (i)pi-(i)pi Interaction introduced to describe the interactions in these structures. The energy decomposition analysis revealed the importance of electrostatic and dispersion forces in stabilizing the stacking of pi-electronic ions, as observed through crystal-state absorption spectra and transient absorption spectroscopy.
Article
Materials Science, Multidisciplinary
Joonhyung Lim, Yun Chang Choi, Dongsun Choi, I-Ya Chang, Kim Hyeon-Deuk, Kwang Seob Jeong, Kyungwon Kwak, Minhaeng Cho
Summary: Investigating the separate dynamics of electrons and holes is crucial for understanding semiconducting nanomaterials. Recent studies on n-type self-doped colloidal quantum dots have revealed unprecedented ultrafast intraband Auger processes and electron relaxation between spin orbit coupling states in the conduction band, providing insights into electron dynamics in higher quantum states coupled to surface states of CQDs.