Article
Chemistry, Physical
Xian Wang, Dayujia Huo, Xin Wang, Minjie Li, Yong Wang, Yan Wan
Summary: The photophysical properties of surface passivated CsPbI3 perovskite were investigated using transient absorption spectroscopy. The results showed that surface passivation slowed down carrier trapping and accelerated bimolecular recombination, leading to improved carrier transport and longer hot carrier lifetime. Defect passivation was found beneficial for enhancing defect tolerance and slowing down hot carrier cooling in developing high-performance photovoltaics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Multidisciplinary Sciences
Herath P. Piyathilaka, Rishmali Sooriyagoda, Hamidreza Esmaielpour, Vincent R. Whiteside, Tetsuya D. Mishima, Michael B. Santos, Ian R. Sellers, Alan D. Bristow
Summary: The research focuses on the photoexcited carrier dynamics in InAs/AlAs0.16Sb0.84 multiple-quantum well sample, revealing significant influences of excitation photon energy and lattice temperature on transient terahertz absorption. With sufficient excess-photon energy, the metastable state transitions to long-lived states. As temperature increases, the long-lived decay times also increase.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Z. Ouzit, G. Baillard, J. Liu, B. Wagnon, L. Guillemeney, B. Abecassis, L. Coolen
Summary: This study compares the luminescence decay dynamics of single CdSe nanoplatelets, clusters of a few platelets, and self-assembled chains. The luminescence decay becomes faster as the number of stacked platelets increases, indicating the FRET-mediated effect of quenchers. Additionally, a slow decay component is observed for both single platelets and platelet chains, suggesting trapping-detrapping mechanisms in nearby trap states. Toy models are developed to analyze the effects of FRET-mediated quenching and trapping on decay curves.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Soumya Mukherjee, Anjan Kumar Nm, Ayan Mondal, Venkataramanan Mahalingam, N. Kamaraju
Summary: This study investigates the excited carrier dynamics of MoSe2 nanosheets through non-degenerate pump-probe differential transmission measurements. The results reveal that the trapping and absorption of excitons occur with time constants of approximately 430 to 500 fs, while the recombination of excitons happens through two decay channels with time constants of approximately 25 to 55 ps and greater than or similar to 1 ns. The rate of exciton-exciton annihilation is estimated to be in the range of 10-8 to 10-8 cm(3)s(-1).
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Xiao-Yi Liu, Yu Cui, Jia-Pei Deng, Yi-Yan Liu, Xu-Fei Ma, Yu-Xuan Hou, Jun-Ye Wei, Zhi-Qing Li, Zi-Wu Wang
Summary: In this study, a method of a full-configuration defect based on the well-known Huang-Rhys model is developed to study the multiphonon processes of charge carrier trapping by various defects in metal halide perovskites quantum dots (MHPQDs). The trapping time dependence on the radius of quantum dot, defect depth, and temperature is investigated. These findings not only enhance our understanding of charge carrier trapping processes by defects, but also provide insights for the designs of MHPQDs-based photovoltaic and photoelectric devices.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
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
Yonglei Sun, Hua Zhu, Na Jin, Ou Chen, Jing Zhao
Summary: Lifetime blinking, a phenomenon of fluctuations in the fluorescence lifetime of a single quantum dot over time while its fluorescence intensity remains relatively stable, has been reported in a few QD systems. In this study, statistical methods demonstrate that compact CdSe/CdS core/shell QDs also exhibit short-lived lifetime blinking events, possibly due to the activation of efficient nonradiative processes leading to intensity blinking.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Applied
Yasuhiko Takeda, Shunsuke Sato, Takeshi Morikawa
Summary: We investigated the application of hot-carrier extraction in solar cells and photocatalysts for artificial photosynthesis, and compared the differences between these two applications: hot-carrier solar cells (HC-SCs) and hot-carrier photocatalysts (HC-PCs) through detailed balance calculations. We found that the hot-carrier effect is less significant in the photocatalysts compared to the solar cells, due to the larger bandgaps required for generating high-energy carriers for the reactions. However, impact ionization and Auger recombination (IA) significantly improve the efficiency of HC-PCs by functioning as photon upconverters and narrowing the optimal bandgap, while also enhancing the spectral robustness.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Anton A. Babaev, Anastasiia Sokolova, Sergei A. Cherevkov, Kevin Berwick, Alexander Baranov, Anatoly Fedorov, Aleksandr P. Litvin
Summary: This study proposes a model based on Auger recombination and energy transfer to explain the dependence of average PL lifetime on the component ratio in the rGO/QD system. Additional experiments and mathematical simulation support the role of excess holes in the QDs and the importance of energy transfer between neighboring QDs in quenching the PL.
Article
Chemistry, Physical
Gerard Michael Carroll, Rens Limpens, Gregory F. Pach, Yaxin Zhai, Matthew C. Beard, Elisa M. Miller, Nathan R. Neale
Summary: This study shows that changing the functional groups on the surface of silicon nanocrystals can slow Auger recombination rates, with thiolate groups elongating the recombination time. These findings highlight the potential positive impact of chemical species with mid-gap surface states under high-rate absorption/emission conditions.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Energy & Fuels
Lachlan E. Black, Daniel H. Macdonald
Summary: The study quantifies the ambipolar Auger coefficient C-amb in crystalline silicon by exploiting the injection dependence of surface recombination with highly charged dielectric films. The determined value of C-amb is found to be independent of the dopant concentration for moderately doped samples near 300 K. The study also offers a revised parameterisation of the Auger recombination rate in c-Si based on the findings, which is consistent with recent record lifetimes reported by other authors.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Physical
Sichao Du, Hao Xie, Juxin Yin, Yunlei Sun, Qiuting Wang, Hong Liu, Wei Qi, Chunfeng Cai, Gang Bi, Duo Xiao, Wenchao Chen, Xiaoyan Shen, Wen-Yan Yin, Rongkun Zheng
Summary: The capability of graphene to generate hot electrons is experimentally demonstrated in Bernal stacking sequence nano-graphite films, showing a strong correlation between the layer number and hot electron scattering. This enables the spectral coverage of hot electrons from mid-infrared to near-infrared energy levels, leading to a high density of populated hot electrons for mid-infrared photodetection. The thickness dependence electron thermalization property of the graphitic material provides a way to design ultrafast and sensitive mid-infrared photodetectors.
Article
Chemistry, Multidisciplinary
Andre Maier, Fabian Strauss, Pia Kohlschreiber, Christine Schedel, Kai Braun, Marcus Scheele
Summary: The intrinsic response time and bandwidth of lead sulfide nanocrystal photodetectors were investigated using a two-pulse coincidence photoresponse technique. The results indicated an intrinsic response time of approximately 1 ns and an intrinsic bandwidth of approximately 0.55 GHz. Auger recombination assisted by nanocrystal surface defects was identified as the dominant mechanism. The intrinsic response time could be further tuned by controlling ligand coverage and trap states.
Article
Materials Science, Multidisciplinary
Andrew A. Marder, James Cassidy, Dulanjan Harankahage, Jacob Beavon, Luis Gutierrez-Arzaluz, Omar F. Mohammed, Aditya Mishra, Austen C. Adams, Jason. D. Slinker, Zhongjian Hu, Stephen Savoy, Mikhail Zamkov, Anton V. Malko
Summary: Compared to zero-dimensional (0D) semiconductor quantum dots, 2D semiconductor nanoplatelets (NPLs) offer a spectrally narrow luminescence and superior absorption coefficients. However, optical devices based on NPLs still suffer from nonradiative Auger decay, which limits the efficiency of various processes. In this study, it is demonstrated that Auger recombination is strongly suppressed in spherically shaped nanoplatelets called quantum shells (QSs), leading to improved performance in terms of biexciton emission yield, amplified spontaneous emission, and electroluminescence enhancement. These results are significant for the development of solution-processed colloidal lasers and LEDs.
ACS MATERIALS LETTERS
(2023)
Article
Physics, Applied
Sayan Prodhan, Kamlesh Kumar Chauhan, Manobina Karmakar, Anima Ghosh, Sayan Bhattacharyya, Prasanta Kumar Datta
Summary: Organic-inorganic halide perovskite is the leading absorber material for highly efficient solar cells. Incorporating metallic nanoparticles enhances the optoelectronic properties by improving solar energy transfer and promoting carrier transport. Adding a dielectric shell over the metal nanoparticles further enhances carrier mobility and reduces carrier recombination in the semiconductor material.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Joshua C. Kays, Alexander M. Saeboe, Reyhaneh Toufanian, Danielle E. Kurant, Allison M. Dennis
Article
Materials Science, Multidisciplinary
Xiaowei Wang, Yuyu Li, Reyhaneh Toufanian, Leonard C. Kogos, Allison M. Dennis, Roberto Paiella
ADVANCED OPTICAL MATERIALS
(2020)
Article
Chemistry, Multidisciplinary
Thuy T. Nguyen, Margaret Chern, R. C. Baer, James Galagan, Allison M. Dennis
Article
Nanoscience & Nanotechnology
Mingfu Chen, Chloe Grazon, Prerana Sensharma, Thuy T. Nguyen, Yunpeng Feng, Margaret Chern, R. C. Baer, Nitinun Varongchayakul, Katherine Cook, Sebastien Lecommandoux, Catherine M. Klapperich, James E. Galagan, Allison M. Dennis, Mark W. Grinstaff
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Multidisciplinary
Margaret Chern, Padric M. Garden, R. C. Baer, James E. Galagan, Allison M. Dennis
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Physical
Reyhaneh Toufanian, Margaret Chern, Victoria H. Kong, Allison M. Dennis
Summary: The study investigates the impact of core composition, shell composition, and shell thickness on the optical properties of semiconductor nanocrystal quantum dots, revealing the ability to produce brightness-matched green and red emitters by adjusting the thickness of the ZnSe shell.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Alexander M. Saeboe, Alexey Y. Nikiforov, Reyhaneh Toufanian, Joshua C. Kays, Margaret Chern, J. Paolo Casas, Keyi Han, Andrei Piryatinski, Dennis Jones, Allison M. Dennis
Summary: This report showcases the reddest emitting indium phosphide quantum dots to date, demonstrating tunable near-infrared photoluminescence and PL multiplexing in the first optical tissue window while avoiding toxic constituents. By utilizing an inverted QD heterostructure, the synthesis overcomes the growth bottleneck and extends the emission peak of the nanoparticles into the deeper optical tissue window.
Article
Chemistry, Physical
Reyhaneh Toufanian, Xingjian Zhong, Joshua C. Kays, Alexander M. Saeboe, Allison M. Dennis
Summary: The study investigated ZnSe QDs with diameters ranging from 2 to 6 nm using various characterization techniques, and proposed empirical fit equations correlating QD size with its properties. The results revealed a nonstoichiometric Zn:Se ratio in ZnSe QDs, providing support for their reliable and consistent use in complex heterostructures and devices.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Joshua C. Kays, Carl R. Conti, Artemis Margaronis, Jason E. Kuszynski, Geoffrey F. Strouse, Allison M. Dennis
Summary: Plasmonic semiconductor nanocrystals offer higher control of localized surface plasmon resonance than metallic materials, with earth-abundant copper iron sulfides as potential alternatives. Bornite NCs exhibit changes in absorbance spectra and metal oxidation during synthesis, indicating potential applications. Understanding the relationship between particle structure and optical properties will aid in the continued development of heavy metal-free plasmonic semiconductor nanoparticles.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Abigail Rendos, Wenhan Cao, Margaret Chern, Marco Lauricella, Sauro Succi, Jorg G. Werner, Allison M. Dennis, Keith A. Brown
Summary: A suspension of nanoparticles can assemble into a macroscopic cellular phase that consists of particle-rich walls and particle-free voids under the influence of AC and DC voltages. This mechanism involves electrophoretic assembly and electrohydrodynamic flow-mediated spinodal decomposition. This work not only reveals the mechanism of cellular phase formation, but also presents a method to reversibly assemble nanoscale particles into microscale continuous structures.
Article
Chemistry, Multidisciplinary
Xingda An, Joshua C. Kays, Ian Lightcap, Tianhong Ouyang, Allison M. Dennis, Bjorn M. Reinhard
Summary: The study integrates gold nanorods and chalcopyrite nanocrystals into water-stable nanocomposites for robust and bifunctional photocatalysis of oxygen and hydrogen evolution reactions. Excitation of gold nanorods or chalcopyrite nanocrystals correlates with increased hydrogen or oxygen evolution, with the direction of light-driven electron transfer depending on the wavelength.
Article
Chemistry, Physical
Jason E. Kuszynski, Joshua C. Kays, Carl R. Conti, Stephen A. McGill, Allison M. Dennis, Geoffrey F. Strouse
Summary: The impact of a magneto-structural phase transition on the carrier effective mass in Cu5FeS4 semiconductor nanocrystals was examined using magnetic circular dichroism. It was found that the behavior of carriers is influenced by the magnetic field.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Chloe Grazon, Margaret Chern, Patrick Lally, R. C. Baer, Andy Fan, Sebastien Lecommandoux, Catherine Klapperich, Allison M. Dennis, James E. Galagan, Mark W. Grinstaff
Summary: This study systematically compared the effects of organic and inorganic dyes in biosensors, as well as the impact of the position of FRET donors or acceptors on biomolecular components on sensor performance. By examining different biosensor configurations through experimental and computational approaches, researchers identified key molecular parameters influencing sensor performance and provided design guidelines for future intermolecular biosensors based on FRET.
Proceedings Paper
Engineering, Biomedical
Reyhaneh Toufanian, Victoria H. Kong, Allison M. Dennis
COLLOIDAL NANOPARTICLES FOR BIOMEDICAL APPLICATIONS XV
(2020)
Article
Chemistry, Analytical
Margaret Chern, Reyhaneh Toufanian, Allison M. Dennis
