Article
Nanoscience & Nanotechnology
Christine Schedel, Fabian Strauss, Krishan Kumar, Andre Maier, Kai M. Wurst, Patrick Michel, Marcus Scheele
Summary: The time-resolved photocurrent response of CdSe quantum dot thin films sensitized with zinc beta-tetraaminophthalocyanine on different substrates was investigated. It was found that polyimide substrates provide larger optical bandwidth compared to glass. Evaluation of the transient photocurrent showed a combination of carrier recombination and trapping events within 2.7 ns, with less pronounced trapping events on polyimide leading to higher bandwidth.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Ning Du, Yingqi Cui, Li Zhang, Mingli Yang
Summary: This study investigates the electron injection process in quantum dot-sensitized solar cells through first-principles calculations, revealing that doping Mn atoms can enhance the electron injection rates, potentially by strengthening injection channels and QD-substrate coupling.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Analytical
Mijin Kim, Dongjin Kim, Ohun Kwon, Honyeon Lee
Summary: The reliable manufacture of flexible transparent electrode is important for the fabrication of high-performance, flexible QLEDs. In this study, we deposited a transparent oxide/metal/oxide (OMO) electrode on a polymer planarization layer and achieved good electron supply and injection. The high-performance flexible QLEDs fabricated using these electrodes had significantly higher current efficiency than rigid QLEDs with ITO electrodes.
Article
Physics, Applied
Ryoichi Akimoto
Summary: The study investigates the formation of quantum dots (QDs) induced by electron beam irradiation onto a highly strained CdSe layer on ZnSe (001). In situ reflection high-energy electron diffraction is used to monitor QD formation and surface morphology. QD formation is confirmed by observing nanoscale three-dimensional islands using transmission electron microscopy and the emission of a single QD at room temperature using photoluminescence microscopy. Electron beam irradiation increases QD size and shifts the emission from green to yellow spectral region.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Engineering, Civil
Xiran Liu, Dan Zhao, Nay Lin Oo
Summary: This paper examines the effects of applying three Savonius wind turbines with different mounting positions on power coefficients by conducting high-fidelity three-dimensional numerical simulations. It is found that laterally placed turbines on a flat surface can increase the maximum mean power coefficient by approximately 5%, while implementing the turbines at different positions on a fixed step can improve the maximum mean power coefficient by as high as 230%. Additionally, there is an optimal lateral spacing between the two adjacent turbines for the maximum mean power coefficient.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Chemistry, Physical
Lingaraj Behera, Debasish Pati, Binod Bihari Sahu, Sasmita Mohapatra
Summary: Manganese dioxide-carbon dot composite nanoparticles have been synthesized and can be used for various applications. This nanobionic sensor shows selective and sensitive response to arsenite and can also detect organoarsenic and organothioarsenic compounds. Additionally, it can monitor arsenic in a plant root vascular system and sense temperature changes.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Engineering, Electrical & Electronic
Dongjin Kim, Seyoung Lee, Jimyoung Kim, Honyeon Lee
Summary: We investigated the electroluminescence mechanisms of QLEDs, focusing on charge carrier trapping/detrapping. Multilayer QD EMLs have low void density and numerous QD surface traps, resulting in high efficiency at low bias voltages and gradually decreasing efficiency at high bias voltages. Transient EL and impedance spectroscopy analyses revealed the roles of traps and charge carrier trapping/detrapping in QLED EL. The trapping/detrapping of charge carriers in the low bias voltage region in QLEDs with a multilayer QD EML promoted charge injection, rapid initiation of EL, and high current efficiency. Contrary to conventional views, traps improved QLED performance.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
A. Longo, B. Notebaert, A. Chevillot, M. Gaceur, R. Messina, A. Durnez, T. Baptiste, C. Dupuis, A. Madouri, N. Battaglini, S. Ammar
Summary: By exploiting the configuration of an alternate-current thin-film electroluminescent device, we achieved light emission through a mechanism of local charge creation and transport, paving the way for cost-effective deposition methods for the active layer and providing insights for the development of non-toxic quantum-dot-based displays.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Francis Agada, Zameer Abbas, Khush Bakht, Asad Muhammad Khan, Umar Farooq, Muhammad Bilal, Muhammad Arshad, Abdul Faheem Khan, Afzal Hussain Kamboh, Ahson Jabbar Shaikh
Summary: This study fabricates complete quantum dot based hole and electron transport layers for perovskite solar cells using hybrid compositions including carbon and inorganic based quantum dots. By plotting and extrapolating experimental efficiency against the percentage composition of quantum dots in the electron transport layer, the unknown efficiencies of other compositions can be estimated with a minimal set-up. The smart minimal set-up design allows for maximum information extraction in a minimum time period for a range of perovskite solar cells.
Article
Optics
Z. C. He, J. Meng, Y. J. Li, F. S. Jia, N. Khan, B. Niu, L. Y. Huang, Z. M. Hu, J. G. Li, J. G. Wang, Y. M. Zou, B. R. Wei, K. Yao
Summary: The optical spectra of Fe-like Mo16+ and Mn-like Mo17+ ions were measured using a new low-energy electron-beam ion trap at Fudan University. A total of eleven lines were observed and ten of them were measured for the first time. Spectra modeling based on collisional-radiative modeling showed reasonable agreement with experimental results. The electron-density dependence of line intensity ratios was investigated and several ratios were found to be sensitive to the electron density, demonstrating potential applications for plasma diagnostics.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2022)
Article
Chemistry, Physical
Manoj Kumar, Sanju Rani, Pargam Vashistha, Animesh Pandey, Govind Gupta, Sudhir Husale, V. N. Singh
Summary: This study presents the photodetection properties of SnSe film deposited on soda-lime glass, showing fast response and recovery times in the visible and IR regions. Time-resolved photoluminescence analysis revealed carrier dynamics and indicated that electron-hole recombination may be responsible for the low resistivity in the device. Through detailed characterization, the study identified areas for future improvement in photodetector device performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Brian Malile, Rana Sodhi, Jennifer I. L. Chen
Summary: We investigated the reduction of organic compounds photocatalyzed by Mn2+-doped CdS/ZnS quantum dot (Mn:CdS/ZnS QD) films. The incorporation of Mn2+ ions into CdS nanocrystals as a dopant promotes Auger cross-relaxation, yielding hot electrons with high reducing power. The Mn:CdS/ZnS QDs exhibited superior performance in various organic reactions and significantly enhanced the efficiency of photoreduction reactions.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Engineering, Electrical & Electronic
Christian Schleich, Dominic Waldhoer, Al-Moatasem El-Sayed, Konstantinos Tselios, Ben Kaczer, Tibor Grasser, Michael Waltl
Summary: In this study, the extended two-state model was used to reproduce leakage current characteristics of two selected technologies. The temperature-activated leakage mechanism in the first technology was identified to have charge transition centers distributed within a few nanometers from the interface. In the second technology, self-trapped electrons were identified as a likely cause for the characteristics and transient charge trapping currents.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Proceedings Paper
Materials Science, Multidisciplinary
Oleh Kuzyk, Roman Peleshchak, Olesya Dan'kiv
Summary: A model of CdSe quantum dot with a multilayer shell undergoing mechanical deformation was constructed. The model takes into account the influence of external hydrostatic pressure, Laplace surface pressure, and lattice parameter mismatch of the contacting materials in the nanoheterosystem. The analysis showed that the baric coefficient of CdSe/ZnS/CdS/ZnS quantum dot can have two possible values depending on the magnitude of external pressure for small cores with a three-layer shell. The use of this model for studying the interaction of quantum dots with elements of biological systems through elastic deformation field was also discussed.
MATERIALS TODAY-PROCEEDINGS
(2022)
Article
Physics, Atomic, Molecular & Chemical
Weronika Biela-Nowaczyk, Pedro Amaro, Filipe Grilo, Andrzej Warczak
Summary: Recombination processes in electron-ion collisions are crucial, particularly multielectron recombination processes, which provide insights into electron-electron interactions. This study used an EBIT at Jagiellonian University to investigate K-LL, K-LM, K-LN, K-LO, and K-MM resonances through X-ray spectroscopy. The research aimed to examine the contribution of inter-shell higher-order recombination processes in the collected spectra, with the K-LL dielectronic recombination spectrum providing resolution to distinguish structures for ions ranging from He-like to C-like Ar.
Review
Chemistry, Multidisciplinary
Avik Das, Tushar Debnath
Summary: Lead-halide perovskite nanocrystals (PNCs) have great potential as optoelectronic material due to their solution processability, color tunability and high photoluminescence quantum yield. The challenge lies in their long-term stability, but recent research has shown that water-triggered chemical transformation can lead to shape-controlled and stable PNCs. Encapsulating PNCs with polymer can also improve their water solubility. This review discusses the progress in using water-hexane interface chemistry to transform PNCs and their potential application in bio-imaging.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Mihir Manna, Tushar Debnath, Satyapriya Bhandari
Summary: In this study, a white light emitting nanocomposite was constructed by chemically coupling halide perovskite nanocrystals with a metal quinolate complex. The coupling process did not affect the morphology, size, and dopant oxidation state of the nanocrystals, while providing additional environmental stability. The resulting nanocomposite exhibited bright white light emission properties close to those of midday sunlight.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Mihir Manna, Srimanta Pal, Tanmay Goswami, Satyapriya Bhandari, Tushar Debnath
Summary: The choice of surface functionalized ligands is crucial in tailoring the optoelectronic properties of semiconductor nanocrystals. In this study, we used a small bidentate molecule called 8-hydroxyquinoline (HQ) to functionalize CsPbX3 perovskite nanocrystals (X = Cl, Br, I). Our experimental results revealed a halogen-hydrogen bonding formation in HQ-functionalized CsPbCl3 and CsPbBr3 nanocrystals, enabling fast charge transfer from the nanocrystals to the HQ molecule within 540 fs. However, weak chelation was observed in HQ-coupled CsPbI3 nanocrystals without an active charge transfer process. The understanding of these distinct surface coupling mechanisms has significant implications in the development of optoelectronics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Jiawen Fang, Yiou Wang, Mariam Kurashvili, Sebastian Rieger, Wiktor Kasprzyk, Qingli Wang, Jacek K. Stolarczyk, Jochen Feldmann, Tushar Debnath
Summary: Photocatalytic water splitting is a promising approach for sustainable hydrogen production. To improve the efficiency, photobasic carbon dots with internal pyridinic N sites were designed to promote the abstraction of protons from water molecules. The ultrafast spectroscopic measurements showed proton abstraction within a few picoseconds of excitation, and the carbon dots also demonstrated a unique four-level lasing scheme in water.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Avik Das, Tushar Debnath
Summary: Controlling light reabsorption in emitting materials is crucial for improving the performance of light-emitting devices. In this study, we prepared a series of size-dependent Cs(Mn/Pb)Cl-3 alloy nanoplatelets with a significant enhancement in the exciton Stokes shift. By utilizing an interfacial Mn-alloying process, we achieved a large exciton Stokes shift of 600 meV in 2 ML Cs(Mn/Pb)Cl-3 NPls. We also proposed a model based on the charge transfer process between Mn2+ and Mn3+ to explain the observed phenomenon.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Ren-Wu Huang, Xin Song, Shulin Chen, Jun Yin, Partha Maity, Jiayi Wang, Bingyao Shao, Hongwei Zhu, Chunwei Dong, Peng Yuan, Taimoor Ahmad, Omar F. F. Mohammed, Osman M. M. Bakr
Summary: Zero-dimensional (0D) scintillation materials are of great interest for the fabrication of flexible high-energy radiation scintillation screens. Challenges still persist in the development of 0D scintillators, but a strategy based on metal nanoclusters shows promise in overcoming these limitations. This work demonstrates the synthesis and self-assembly of atomically precise nanoclusters with high phosphorescence quantum yield, AIEE behavior, and intense radioluminescence. The self-assembled nanoclusters can be used as building blocks for flexible particle-deposited scintillation films with high-resolution X-ray imaging performance.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Nanoscience & Nanotechnology
Noor A. Merdad, Yue Wang, Omar Alkhazragi, Zyad O. F. Mohammed, Partha Maity, Luis Gutierrez-Arzaluz, Haoze Yang, Rounak Naphade, Chun Hong Kang, Tien Khee Ng, Osman M. Bakr, Boon S. Ooi
Summary: In this study, the authors fabricated cesium lead bromide (CsPbBr3) thin films of varying thicknesses and investigated their visible-light communication (VLC) performance. Thicker films were found to have a more homogeneous surface and fewer surface trap states than thinner films. The 20-nm-thick CsPbBr3 film exhibited the best performance with a -3-dB bandwidth of 30.7 MHz and a net data rate of 330 Mb/s, making it suitable for high-power, high-speed, and large-area transmission and detection of visible-light signals.
Article
Chemistry, Physical
Jiawen Fang, Ping Li, Xudong Xue, Hui Li, Dongyue Cui, Jingyu Zhang, Yang Wang, Tushar Debnath, Yanni Jie, Wei Huang, Runfeng Chen
Summary: Aggregation significantly affects the organic room-temperature phosphorescence (RTP), especially in molecules with D-A architectures, but the underlying mechanism is not yet well understood. By constructing different D-A aggregates in solid films, the fluorescence and phosphorescence from the locally excited and intramolecular charge-transfer states can be modulated. The dihedral angle between D and A units is found to control the electronic communication, resulting in enhanced D-A coupling and reduced ICT at shrinking angles, leading to energy realignment and promoting RTP from the molecular aggregates.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xi Chen, Noreen Rehmat, Ivan V. Kurganskii, Partha Maity, Ayhan Elmali, Jianzhang Zhao, Ahmet Karatay, Omar F. Mohammed, Matvey V. Fedin
Summary: Bodipy (BDP)-perylenebisimide (PBI) donor-acceptor dyads/triad were synthesized to investigate the spin-orbit charge-transfer intersystem crossing (SOCT-ISC). Different quantum yields of singlet oxygen were observed for the dyads/triad, and various processes including FRET, CS, CR, and TTET were observed in the excited state dynamics. Time-resolved electron paramagnetic resonance spectroscopy revealed the involvement of both radical pair ISC and SOCT-ISC in the intersystem crossing. The triad BDP-PBI-2 showed an unusual electron spin polarization pattern of (e, e, e, e, e, e) in the triplet state formed via the RP ISC mechanism.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Mihir Manna, Srimanta Pal, Tanmay Goswami, Satyapriya Bhandari, Tushar Debnath
Summary: The choice of surface functionalized ligands is crucial for tailoring the optoelectronic properties of semiconductor nanocrystals (NCs). We used a bidentate 8-hydroxyquinoline (HQ) molecule to surface functionalize CsPbX3 perovskite NCs (X = Cl, Br, I), along with traditional long-chain monodentate ligands. Our experimental results revealed a halogen-hydrogen bonding formation in the HQ functionalized CsPbCl3 and CsPbBr3 NCs, which facilitated fast charge transfer from the NCs to the HQ molecule. In contrast, weak chelation was observed in HQ-coupled CsPbI3 NCs without an active charge transfer process.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Sourav Maiti, Laurens D. A. Siebbeles
Summary: In this Perspective, recent advances in harvesting triplets for photovoltaic and photon upconversion applications are overviewed. The two angles discussed are singlet fission-sensitized solar cells and triplet-triplet annihilation upconversion using transition metal dichalcogenides (TMDCs) and organic semiconductors.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Debadrita Bhattacharya, Arin Bhakat, Tushar Debnath
Summary: Researchers have successfully controlled the self-assembly of Te-based MnCs to arrest the growth of AgInTe2 quantum dots (QDs) by using a synergistic capping agent. This has led to the formation of evenly distributed AgInTe2-ZnS Janus nanocrystals with significantly reduced Te-oxidative properties.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Wasim J. Mir, Tariq Sheikh, Saidkhodzha Nematulloev, Partha Maity, Khursand E. Yorov, Abdul-Hamid Emwas, Mohamed Nejib Hedhili, Mudeha Shafat Khan, Mutalifu Abulikemu, Omar F. Mohammed, Osman M. Bakr
Summary: This study reports a method for synthesizing high-quality and size-tunable InSb CQDs using commercially available precursors and under standard colloidal synthesis conditions. By changing the surface ligands of the CQDs, an increase in excited-state lifetime, efficient carrier multiplication, and slower carrier annihilation are observed. This work overcomes a major challenge in synthesizing high-quality InSb CQDs and opens up new possibilities for Pb- and Hg-free CQDs in SWIR applications.
Article
Chemistry, Multidisciplinary
Tariq Sheikh, Wasim J. Mir, Saidkhodzha Nematulloev, Partha Maity, Khursand E. Yorov, Mohamed Nejib Hedhili, Abdul-Hamid Emwas, Mudeha Shafat Khan, Mutalifu Abulikemu, Omar F. Mohammed, Osman M. Bakr
Summary: InAs colloidal quantum dots (CQDs) have emerged as candidate lead- and mercury-free solution-processed semiconductors for infrared technology due to their appropriate bulk bandgap and promising charge-carrier transport properties. However, the lack of suitable arsenic precursors and readily accessible synthesis conditions have limited their size and bandgap range. By controlling the reactivity, we have successfully synthesized monodisperse InAs nanorod CQDs with tunable bandgaps.
Article
Chemistry, Physical
Sachin R. Rondiya, Sawanta S. Mali, Anurag Roy, Gajendra Kumar Inwati, Ganesh K. Rahane, Yogesh A. Jadhav, Sunil Suresh, Tushar Debnath, Chang Kook Hong, Nelson Y. Dzade
Summary: This study investigates the incorporation of Ba2+ at a low concentration into CsPbI2Br, resulting in the formation of mixed CsPb1-xBaxI2Br perovskite films. Photovoltaic devices utilizing these Ba-doped CsPbI2Br (Ba-CsPbI2Br) perovskite films achieved a higher stabilized power conversion efficiency of 14.07% compared to 11.60% for pure CsPbI2Br films. The improved device performance can be attributed to the efficient transport of conduction electrons across the interface between Ba-CsPbI2Br and the TiO2 electron transporting layer (ETL).
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
