Article
Chemistry, Multidisciplinary
Sarah R. E. Orsborne, Jeffrey Gorman, Leah R. Weiss, Akshay Sridhar, Naitik A. Panjwani, Giorgio Divitini, Peter Budden, David Palecek, Sean T. J. Ryan, Akshay Rao, Rosana Collepardo-Guevara, Afaf H. El-Sagheer, Tom Brown, Jan Behrends, Richard H. Friend, Florian Auras
Summary: In this study, DNA-encoded assembly of pentacenes capable of singlet fission (SF) was used to achieve precise structural control and explore the SF process. The results showed that SF evolved through a quintet state and demonstrated efficient and controlled semiconductor operation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Dallas P. Strandell, Patanjali Kambhampati
Summary: We performed time-resolved photoluminescence (t-PL) measurements on CsPbBr3 perovskite nanocrystals with a time resolution of 3 ps. Surprisingly, even though these nanocrystals are weakly confined or bulk-like, emissions from multiexcitons were observed with binding energies consistent with strongly confined quantum dots. Both biexciton and triexciton emissions were observed, and the kinetics of the multiexciton populations were analyzed in spectrally integrated form as well as decomposed into exciton, biexciton, and triexciton populations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Chaochao Qin, Jiajia Guo, Zhongpo Zhou, Yufang Liu, Yuhai Jiang
Summary: Lead chalcogenide quantum dots have been found to exhibit strong quantum confinement effects. This paper explores the dynamics of excitons in PbS QDs, revealing that the cooling of hot excitons and Auger recombination of multiexcitons are influenced by the pump-photon energy and pump-pulse energy. There is a competitive relationship between the generation of multiexcitons and the cooling of hot excitons in PbS QDs.
Article
Optics
K. Mouloudakis, G. Vasilakis, V. G. Lucivero, J. Kong, I. K. Kominis, M. W. Mitchell
Summary: This study presents a first-principles analysis of the noise spectra of alkali-metal vapors in and out of the spin-exchange-relaxation-free (SERF) regime. The study predicts nonintuitive features that have the potential to improve the sensitivity of SERF media, and highlights their importance in quantum optical applications.
Article
Chemistry, Physical
Dipti Jasrasaria, Eran Rabani
Summary: Nonradiative processes control the efficiencies of semiconductor nanocrystal-based devices, and hot exciton cooling is a central process in which highly excited electron/hole pairs relax to form band-edge excitons through nonradiative means. However, the timescale and mechanism of cooling in nanocrystals are not well understood due to quantum confinement effects. Experimental measurements of the cooling timescale range six orders of magnitude.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Multidisciplinary Sciences
Yusuke Kawashima, Tomoyuki Hamachi, Akio Yamauchi, Koki Nishimura, Yuma Nakashima, Saiya Fujiwara, Nobuo Kimizuka, Tomohiro Ryu, Tetsu Tamura, Masaki Saigo, Ken Onda, Shunsuke Sato, Yasuhiro Kobori, Kenichiro Tateishi, Tomohiro Uesaka, Go Watanabe, Kiyoshi Miyata, Nobuhiro Yanai
Summary: Singlet fission (SF) can create spin-polarized quintet states in organic systems, and here the authors demonstrate that SF in supramolecular assemblies of pentacene chromophores improves the sensitivity of magnetic resonance of water molecules through dynamic nuclear polarization in a water-glycerol glass.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Junhui Wang, Lifeng Wang, Shuwen Yu, Tao Ding, Dongmei Xiang, Kaifeng Wu
Summary: Understanding and manipulating hot electron dynamics in semiconductors could lead to innovative energy conversion technologies. By studying electron-doped CdSe quantum dots, the researchers observed different relaxation mechanisms of hot electrons at various doping levels and were able to prolong the hot electron lifetime up to 320 picoseconds, offering new opportunities for hot electron harvesting in doped quantum dots.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Ho Jin, Clement Livache, Whi Dong Kim, Benjamin T. Diroll, Richard D. Schaller, Victor I. Klimov
Summary: The authors achieve a threefold enhancement in multiexciton yields in Mn-doped PbSe/CdSe quantum dots by exploiting spin-exchange interactions. These interactions outpace phonon emission losses and overcome the limitation of carrier multiplication. This study demonstrates the potential of spin-exchange carrier multiplication in advanced photoconversion.
Article
Optics
Clement Livache, Whi Dong Kim, Ho Jin, Oleg Kozlov, Igor Fedin, Victor Klimov
Summary: Researchers have demonstrated that up-conversion in manganese-doped CdSe colloidal quantum dots enables efficient electron photoemission, leading to high-yield production of solvated electrons. This discovery has significant applications in visible-light-driven reduction photochemistry.
Article
Physics, Multidisciplinary
V. V. Belykh, A. R. Korotneva, D. R. Yakovlev
Summary: By simultaneously applying a radio frequency field and periodic optical pulses, this study successfully addresses the issue of inhomogeneity and fluctuating environment affecting the coherence time of an electron spin ensemble. The research resulted in a 50-Hz-narrow electron spin resonance with milliseconds-long T-2 in Ce3+ ions, paving the way for coherent optical manipulation in spin systems decoupled from their inhomogeneous environment.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
John P. Philbin, Amikam Levy, Prineha Narang, Wenjie Dou
Summary: The study of charge and spin transport through semiconductor quantum dots is experiencing a renaissance, with recent advances in nanofabrication and the realization of quantum dots as candidates for quantum computing. The competition between energy spacing and exchange interaction determines the spin states of the lowest quasi-particle energy levels, leading to spin singlet and spin triplet states. Furthermore, the exchange interaction is responsible for spin blockades in transport properties.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Seungjun Lee, D. J. P. de Sousa, Young-Kyun Kwon, Fernando de Juan, Zhendong Chi, Felix Casanova, Tony Low
Summary: In this study, we investigate the twist-angle dependence of spin-orbit coupling proximity effects and charge-to-spin conversion in graphene/WSe2 heterostructures from first principles. We find that the charge-to-spin conversion strongly depends on the twist angle, with optimal standard Rashba-Edelstein and disorder-free spin Hall efficiencies achieved at approximately 30 degrees twisting. The symmetry breaking due to twisting also gives rise to an unconventional Rashba-Edelstein effect, where the electrically generated nonequilibrium spin densities possess spins collinear to the applied electric field. Our work provides a new perspective on the electrical generation of spins in van der Waals heterostructures.
Article
Materials Science, Multidisciplinary
F. L. Pratt, F. Lang, W. Steinhardt, S. Haravifard, S. J. Blundell
Summary: Electron spin dynamics in the triangular-lattice quantum spin-liquid candidate YbZnGaO4 was investigated, revealing no evidence for freezing or ordering of the Yb spins. The muon spin relaxation rate can be decomposed into two contributions, one dependent on longitudinal magnetic field and the other independent of field. The spin-diffusion rate follows the expected form for two-dimensional diffusion of mobile spin excitations, and reduces significantly in the low temperature quantum regime, attributed to the effect of quantum entanglement. Comparison with theory suggests that the nodal spin-liquid model U1A11 provides better agreement with experimental data.
Article
Chemistry, Multidisciplinary
Vasilii V. Belykh, Mikhail L. Skorikov, Evgeniya V. Kulebyakina, Elena V. Kolobkova, Maria S. Kuznetsova, Mikhail M. Glazov, Dmitri R. Yakovlev
Summary: Lead halide perovskite nanocrystals in a glass matrix show excellent optical properties and stability, making them a promising platform for optoelectronic applications. By studying the electron spin properties of these nanocrystals, we uncover their potential for spintronics.
Article
Chemistry, Physical
Ryan W. Tilluck, Nila T. M. Mohan, Caitlin Hetherington, Chase H. Leslie, Sourav Sil, Jared Frazier, Mengliang Zhang, Benjamin G. Levine, P. Gregory Van Patten, Warren F. Beck
Summary: Surface defects and organic surface-capping ligands have been found to impact the photoluminescence properties of semiconductor quantum dots by altering the rates of competing nonradiative relaxation processes. Two-dimensional electronic spectroscopy reveals that absorption of light by quantum dots generates vibronic excitons, and during hot-carrier cooling, coherent wavepacket motions of the ligands are rapidly damped with vibronic coherence transferred to the photoluminescent state. These findings suggest a many-electron, molecular theory for the electronic structure of quantum dots.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Tufan Ghosh, Swarupa Chatterjee, Edamana Prasad
JOURNAL OF PHYSICAL CHEMISTRY A
(2015)
Article
Chemistry, Physical
Tufan Ghosh, Edamana Prasad
JOURNAL OF PHYSICAL CHEMISTRY C
(2015)
Article
Chemistry, Physical
Itay Gdor, Tufan Ghosh, Oleg Lioubashevski, Sanford Ruhman
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2017)
Article
Chemistry, Multidisciplinary
Tufan Ghosh, Sigalit Aharon, Lioz Etgar, Sanford Ruhman
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2017)
Article
Chemistry, Multidisciplinary
Tufan Ghosh, Sigalit Aharon, Adva Shpatz, Lioz Etgar, Sanford Ruhman
Article
Chemistry, Physical
Tufan Ghosh, Sandeepan Maity, Edamana Prasad
JOURNAL OF PHYSICAL CHEMISTRY B
(2014)
Article
Chemistry, Physical
Jayanta Dana, Tufan Ghosh, Itay Gdor, Arthur Shapiro, Efrat Lifshitz, Sanford Ruhman
Summary: The spectator exciton method is used to study the influence of the number of excitons on the absorption of nanocrystals by comparing their absorption spectra. The experiments show that in CdSe nanodots, conflicts in electron spin orientation result in the blocking of 50% of hot electrons from directly cooling to the band edge. In contrast, loading of cold excitons in PbS nanodots leads to a gradual broadening of the 1Se1Sh absorption band, indicating the inadequacy of using a single probe wavelength to measure the filling of band-edge states. Furthermore, the sub band gap induced absorption characteristic of hot exciton states in all quantum dots is not the low-energy half of biexciton shifting to the 1Se1Sh absorption band, but rather part of a broad induced absorption characteristic of hot excitons regardless of the spectator count. Finally, the unique capability of spectator excitons (SXs) to detect contributions of stimulated emission to pump-probe signals is demonstrated in singly excited PbS nanocrystals, where no such contributions are observed.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Review
Chemistry, Multidisciplinary
Vanga Ravali, Tufan Ghosh
Summary: Lead halide perovskites have promising potential as solar cell materials due to their unique photophysical properties. This article focuses on recent experimental developments in understanding the charge carrier dynamics in perovskite materials, including exciton dissociation, charge carrier thermalization, hot carrier cooling, and electron-phonon coupling.
CHEMICAL COMMUNICATIONS
(2023)
Proceedings Paper
Chemistry, Physical
Tufan Ghosh, Sigalit Aharon, Lioz Etgar, Sanford Ruhman
XXI INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA 2018 (UP 2018)
(2019)
Article
Chemistry, Multidisciplinary
P. K. Lekha, Tufan Ghosh, Edamana Prasad
JOURNAL OF CHEMICAL SCIENCES
(2011)
