Article
Chemistry, Multidisciplinary
Madison Monahan, Bin Cai, Tengyue Jian, Shuai Zhang, Guomin Zhu, Chun-Long Chen, James J. De Yoreo, Brandi M. Cossairt
Summary: Peptoids, with a structure similar to proteins, offer a versatile platform for assembling structures with atomic precision. This study demonstrated successful assembly of CdSe QDs using peptoid tubes and sheets via covalent linkages, providing control over QD density. The compatibility and control of CdSe-peptoid interactions through varying peptoid structures and CdSe particles were shown to create complex hybrid structures.
Article
Chemistry, Physical
Arun Ashokan, Paul Mulvaney
Summary: Solution-phase spectroelectrochemistry was used to study electron injection into colloidal CdSe quantum dots in THF. The results showed reversible optical changes on a time-scale of minutes, with the injection of electrons leading to quenching of photoluminescence. The number of electrons injected into the QDs depended on the electrode potential and QD size, with most injection occurring below the band edge.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Analytical
Dongquan Leng, Jihao Zhao, Xiang Ren, Rui Xu, Lei Liu, Xuejing Liu, Yuyang Li, Qin Wei
Summary: In this study, a split-type immunoassay strategy initiated by cation exchange and altering the capacity of an electron donor was optimized, using MoSe2/CdSe as a photoelectrode substrate and silver ions as the initiator of CE. The combination of ascorbate oxidase with MSNs improved the sensor's sensitivity and reliability, resulting in a broad linear range and low detection limit when applied to neuron-specific enolase.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Krishan Kumar, Jonas Hiller, Markus Bender, Saeed Nosrati, Quan Liu, Marc Edelmann, Steffen Maier, Tim Rammler, Frank Wackenhut, Alfred J. Meixner, Kai Braun, Uwe H. F. Bunz, Marcus Scheele
Summary: By assembling CdSe nanocrystals and aggregates of an arylenethynylene derivative into a hybrid thin film, researchers observed dual fluorescence from both fluorophores with periodic anticorrelated fluorescence intensity variations at low temperature. This phenomenon is attributed to the structure-dependent aggregation-induced emission of the arylenethynylene derivative, impacting the rate of excitation energy transfer between the molecules and nanocrystals. This study emphasizes the potential of combining semiconductor nanocrystals with molecular aggregates displaying aggregation-induced emission to generate novel optical properties.
Article
Nanoscience & Nanotechnology
Yauhen Aniskevich, Aliaksandra Radchanka, Artsiom Antanovich, Anatol Prudnikau, Michael T. Quick, Alexander W. Achtstein, Jae Hyeon Jo, Genady Ragoisha, Mikhail Artemyev, Eugene Streltsov
Summary: Electrophoretically deposited quantum dots can be charged electrochemically to alter their electrical and optical properties, with CdSe quantum dots of different diameters demonstrating a strong electrochromic response. The injected electron count increases with QD size, leading to different energy level fillings observed in cyclic voltammetry measurements. Additionally, EPD CdSe QD films show fast charging-discharging kinetics, suggesting potential applications in electrochromic displays and tunable color filters.
ACS APPLIED NANO MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Caitlin R. McGranahan, Guy E. Wolfe, Alejandro Falca, David F. Watson
Summary: The study utilized N,N'-dicyclohexylcarbodiimide (DCC) coupling chemistry to synthesize heterostructures of CdSe and CdTe quantum dots in colloidal dispersions, as well as immobilizing them on metal oxide thin films. The DCC-mediated formation of amide bonds between terminal carboxylic acid and amine groups of ligands on different QDs drove the formation of heterostructures, selectively yielding dispersed or immobilized structures with programmable compositions and energetic offsets. The results showed that the carbodiimide coupling chemistry can efficiently tether colloidal QDs selectively and covalently, enabling excited-state interfacial electron transfer.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Hui Zhang, Xiaohu Mi, Bowen Kang, Yunkai Wu, Tingting Zhang, Pai Liu, Xiaowei Sun, Zhenglong Zhang, Ning Liu, Hongxing Xu
Summary: Colloidal nanocrystals play a significant role in optoelectronic devices and their properties can be improved through ligand modification, which can enhance charge transport and emission characteristics in LEDs.
Article
Physics, Multidisciplinary
Benjamin Russell, Re-Bing Wu, Herschel Rabitz
Summary: This study investigates the control landscapes of closed quantum systems beyond the dipole approximation by including a polarizability term in the Hamiltonian. Singular controls are analyzed as potential landscape traps, with a comparison to the dipole approximation results. The addition of a polarizability term removes traps from the control landscape and restores controllability in otherwise uncontrollable dipole coupled systems.
FRONTIERS IN PHYSICS
(2021)
Article
Physics, Applied
Xi-Kai Yang, Jia-Wei Qiao, Zhi-Hao Chen, Zhen-Chuan Wen, Hang Yin, Xiao-Tao Hao
Summary: By incorporating CdSe quantum dots as a third component, this study has successfully enhanced the current density and power conversion efficiency of organic solar cells. CdSe QDs modulate charge dynamics, increase fluorescence external quantum efficiency, and enable Forster resonance energy transfer and fast charge transfer in BHJ films, resulting in improved overall device performance.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Prachi Rastogi, Eva Izquierdo, Charlie Greboval, Mariarosa Cavallo, Audrey Chu, Tung Huu Dang, Adrien Khalili, Claire Abadie, Rodolphe Alchaar, Stefano Pierini, Herve Cruguel, Nadine Witkowski, James K. Utterback, Thibault Brule, Xiang Zhen Xu, Philippe Hollander, Abdelkarim Ouerghi, Bruno Gallas, Mathieu G. Silly, Emmanuel Lhuillier
Summary: Researchers have developed a new photodiode design that integrates nanocrystals into focal plane arrays, achieving efficient charge dissociation and low dark current. By introducing a thin and strongly coupled CdSe layer, the electrical performance of the diode is significantly improved.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Prachi Rastogi, Eva Izquierdo, Charlie Greboval, Mariarosa Cavallo, Audrey Chu, Tung Huu Dang, Adrien Khalili, Claire Abadie, Rodolphe Alchaar, Stefano Pierini, Herve Cruguel, Nadine Witkowski, James K. Utterback, Thibault Brule, Xiang Zhen Xu, Philippe Hollander, Abdelkarim Ouerghi, Bruno Gallas, Mathieu G. Silly, Emmanuel Lhuillier
Summary: This study improved the design of nanocrystal integration into focal plane arrays by introducing a CdSe layer, significantly enhancing the electrical performance and achieving high responsivity and specific detectivity.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Mihail Elisa, Stefan-Marian Iordache, Ana-Maria Iordache, Madalin Ion Rusu, Gabriel Socol, Mihaela Filipescu, Cristina Bartha, Monica Enculescu
Summary: In this study, a composite material for optoelectronic applications was investigated, involving CdSe-doped glass film prepared by pulsed laser deposition. The optical absorption spectra revealed exciton peaks and the dependence of CdSe quantum dots band gap energy on quantum confinement effect. Photoluminescence of the CdSe-doped film exhibited peaks corresponding to transitions from the excited state to the ground state. The size of CdSe nanoclusters was correlated with different imaging techniques, and specific vibration modes were identified through spectroscopy analyses.
Article
Chemistry, Physical
Jiangzhi Zi, Yueqi Zhong, Zhao Li, Fan Wu, WeiWei Yang, Zichao Lian
Summary: Photoinduced carrier transfer pathways play a role in the optical and electronic properties of nanomaterials for photocatalytic H-2 evolution, while defects in semiconductor nanocrystals can enhance our understanding of photocatalytic mechanisms. CdSe/ZnS HNPLs with anomalous type-I hole transfer exhibit advantages in efficient charge separation and photocatalytic H-2 evolution, compared to type-II CdSe/ZnSe HNPLs and pristine CdSe NPLs. These results elucidate the role of defect-mediated carrier transfer in visible-light-driven photocatalytic H-2 evolution.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Wenke Li, Xiujian Zhao, Francois-Xavier Coudert, Chao Liu
Summary: In this study, the effects of calcium on the atomic and electronic structures of CdSe quantum dots (QDs) were investigated. It was found that the increase in CaO content in glass breaks the linkage between Na and O atoms, but interactions between Cd atoms and nonbridging oxygen atoms remain intact. CdSe QDs promote the migration of Na atoms to the interface and even the interior of QDs, while Ca atoms are only found at the QD/glass interface and in glass matrices far from the QDs. However, the influence of CdSe QDs on the glass structure is limited to a short range near the interface according to the radial concentration distribution. The increase in CaO content also results in an increase in the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap of CdSe QD-embedded glasses. These findings contribute to a better understanding of the effects of calcium on the structural and luminescence properties of CdSe QD-embedded glasses.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Zhen Wu, Yuanyuan Zhang, Rongrong Hu, Meizhen Jiang, Pan Liang, Qing Yang, Li Deng, Tianqing Jia, Zhenrong Sun, Donghai Feng
Summary: The electron spin dynamics in CdSe quantum dots with hole acceptors were investigated using time-resolved ellipticity spectroscopy. Two types of hole acceptors, Li[Et3BH] and 1-octanethiol, resulted in distinctly different electron spin dynamics. Differences were observed in electron g factors, spin dephasing/relaxation times, and mechanisms.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Optics
Vojtech Miller, Karel Zidek
Summary: This paper presents a setup for high-precision transmission measurement of Ti:Sa crystals using Nd:YAG and Er:YAG lasers. By utilizing synchronous detection via a double integrated sphere, the transmission uncertainty of 0.01-0.03% and FoM precision of +/- 7.5% were achieved. Experimental results demonstrate that spatial inhomogeneities and angular mismatch can significantly affect the FoM values.
Article
Chemistry, Physical
Supriya Ghosh, Bapi Pradhan, Weihua Lin, Yiyue Zhang, Luca Leoncino, Pavel Chabera, Kaibo Zheng, Eduardo Solano, Johan Hofkens, Tonu Pullerits
Summary: In the past two decades, research has focused on suppressing Auger recombination in metal-chalcogenide and perovskite nanocrystals (PNCs) for photovoltaic and light emitting device (LED) applications. A study examined dodecahedron cesium lead bromide perovskite nanocrystals (DNCs) and found that they exhibit slower Auger recombination compared to hexahedron nanocrystals (HNCs). The research demonstrates that multiexciton recombinations result in lower Auger recombination rates in DNCs than in HNCs.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Optics
Jiri Junek, Karel Zidek
Summary: The RATS method is proven to be useful for measuring photoluminescence dynamics and fluorescence lifetime imaging. Two fundamental developments are presented: using random digital laser modulation for nanosecond-resolution measurement of photoluminescence dynamics, and using a single-pixel camera experiment for alternative evaluation of fluorescence lifetime imaging. These developments significantly save post-processing time and improve the accuracy stability of FLIM spectrogram.
Article
Optics
Marek Mach, Pavel Psota, Karel Zidek, Pavel Mokry
Summary: A compact lensless method based on digital holographic Fizeau interferometer is developed to image domain patterns in ferroelectric single crystals, providing a large field-of-view image with high spatial resolution. The method utilizes the electro-optic phenomenon to display the domain patterns in the crystal and measure the difference in the index of refraction.
Article
Chemistry, Physical
Albin Hedse, Alex Arash Sand Kalaee, Andreas Wacker, Tonu Pullerits
Summary: The double quantum coherence (DQC) signal in nonlinear spectroscopy provides information about many-body correlation effects that are difficult to obtain through other methods. Contrary to intuition, pulse overlap-related artifacts are not filtered out by the Fourier transform. Careful analysis of experiments is necessary to account for the pulse-overlap artifact.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Daniel Finkelstein-Shapiro, Pierre-Adrien Mante, Sinan Balci, Donatas Zigmantas, Tonu Pullerits
Summary: In polaritons, the properties of matter are modified by mixing molecular transitions with light modes, leading to hybrid light-matter states and modified exciton dynamics. This article rigorously derives non-Hermitian Hamiltonians in the response function formalism of nonlinear spectroscopy and explores spectroscopic signatures of plexcitons. The study reveals interference and Rabi splitting in linear spectroscopy and a qualitative change in the symmetry of the line shape of the nonlinear signal when crossing the exceptional point.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Xinyue Wang, Hongxiang Wang, Meixia Zhang, Tonu Pullerits, Peng Song
Summary: By studying the photoinduced electron transfer properties of the D-D-A molecule ((TPA-TT)-BODIPY-C60) in an external electric field (Fext), the excited-state properties of the molecule and the charge-transfer processes were investigated. The electronic coupling (VDA), reorganization energy (lambda), and free energy (Delta G) were calculated and simulated. It was found that exciton dissociation occurs in the Marcus inverted region and the charge-transfer rate is influenced by the changes in VDA and Delta G. The results provide a method for the design of a new type of electron transfer process with high efficiency in the D-D-A system.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Yanmei He, Siping Liu, Zehan Yao, Qian Zhao, Pavel Chabera, Kaibo Zheng, Bin Yang, Tonu Pullerits, Junsheng Chen
Summary: Low-dimensional perovskite-inspired materials with self-trapped exciton (STE) emission have sparked cutting-edge research in optoelectronics. However, there has been little focus on the intrinsic dynamics of broad emission based on STE in these materials. In this study, through femtosecond transient absorption spectroscopy, we directly observed the ultrafast process of STE formation in Cs2ZrCl6 nanocrystals, and obtained the dynamic rules of ultrafast STE formation. The formed STEs relax to an intermediate STE state with a lifetime of approximately 180 ps before reaching the emissive STE state with a lifetime of about 15 μs. Our work provides a comprehensive and precise dynamic picture of STE emission in low-dimensional metal halides and sheds light on expanding their potential applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Jie Meng, Qian Zhao, Weihua Lin, Tonu Pullerits, Kaibo Zheng
Summary: This study demonstrates the biexciton dynamics of core/shell quantum dots with submonolayer shell coverage. The results show that these quantum dots have a prolonged Auger lifetime. However, unlike conventional quantum dots, the dependence of the Auger recombination time on quantum dot size features two constant stages. This study provides a reference for the application of core-shell quantum dots in optoelectronic devices.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
Qi Shi, Pushpendra Kumar, Tonu Pullerits
Summary: We propose a temperature-dependent intensity modulated two-photon excited fluorescence microscopy technique for mapping charge carrier dynamics in perovskite microcrystal film. By analyzing the emission in harmonics of the excitation modulation frequency, we can study charge carrier recombination processes and potential accumulation effects. Our method allows for a quantitative comparison of different emission channels at a micrometer resolution. We applied this technique to a methylammonium lead bromide perovskite microcrystal film and investigated temperature-dependent modulated imaging, including exciton dissociation, charge carrier trapping-detrapping equilibrium, and phase transition at low temperatures.
ACS PHYSICAL CHEMISTRY AU
(2023)
Article
Chemistry, Multidisciplinary
Nils W. Rosemann, Linnea Lindh, Iria Bolano Losada, Simon Kaufhold, Om Prakash, Aleksandra Ilic, Jesper Schwarz, Kenneth Waernmark, Pavel Chabera, Arkady Yartsev, Petter Persson
Summary: Steady state and ultrafast spectroscopy were used to study [Fe-III(phtmeimb)(2)]PF6 over a broad range of temperatures. The intramolecular deactivation dynamics of the luminescent doublet ligand-to-metal charge-transfer ((LMCT)-L-2) state were analyzed, revealing the direct deactivation of the (LMCT)-L-2 state as a key limitation to its lifetime. Photoinduced disproportionation and subsequent bimolecular recombination of Fe(iv) and Fe(ii) complex pairs were observed in selected solvent environments. The efficient photoinduced intermolecular charge separation over a wide temperature range highlights the potential of [Fe-III(phtmeimb)(2)]PF6 for photocatalytic bimolecular reactions.
Article
Chemistry, Physical
Linnea Lindh, Torbjorn Pascher, Samuel Persson, Yogesh Goriya, Kenneth Warnmark, Jens Uhlig, Pavel Chabera, Petter Persson, Arkady Yartsev
Summary: The excited state dynamics of three iron(II) carbene complexes were investigated, revealing differences in dynamics between the complexes and the metal-centered triplet states. The study provides insights into the deactivation processes of the complexes and improves understanding of the photophysical limitations and opportunities for the use of iron(II) based photosensitizers in photochemical applications.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)