Article
Chemistry, Multidisciplinary
Yuri Y. Bleyan, Paytsar A. Mantashyan, Eduard M. Kazaryan, Hayk A. Sarkisyan, Gianluca Accorsi, Sotirios Baskoutas, David B. Hayrapetyan
Summary: This study presents a theoretical investigation of exciton and biexciton states in a strongly oblate ellipsoidal quantum dot made from GaAs. The study analyzes the energy levels, oscillator strength, optical susceptibilities, and absorption coefficients of the quantum dot.
Article
Multidisciplinary Sciences
Xingtong Chen, Xiongfeng Lin, Likuan Zhou, Xiaojuan Sun, Rui Li, Mengyu Chen, Yixing Yang, Wenjun Hou, Longjia Wu, Weiran Cao, Xin Zhang, Xiaolin Yan, Song Chen
Summary: This study proposes quantum dots with monmonotonically-graded core/shell/shell structures to improve the performance of devices by reducing the surface-bulk coupling. By exploring the degradation mechanism and improving the operational stability of blue electroluminescence, the researchers have achieved significantly improved lifetimes for the bottom-emitting devices.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Huayu Wei, Chenlin Wang, Xiaoxiao Li, Heyan Meng, Bingyi Tong, Luxi Li, Xuepeng Zhan, Bing Jin, Baoqing Sun, Yanmin Zong, Xian Zhao, Yuan Gao
Summary: This study investigates the use of ultraviolet (UV) illumination to treat cadmium chalcogenide colloidal quantum wells (CQWs) prepared using colloidal atomic layer deposition (c-ALD). It is observed that the photoluminescence of the CQWs is significantly improved, with an irreversible 79-fold increase, and the lasing threshold is reduced to two-thirds of the untreated samples, enabling whispering gallery mode lasing from the CQW in solution. This research demonstrates an efficient and convenient method for boosting the emission from the CQWs and highlights the advantages of CQWs as optical gain media that can be engineered with atomic precision.
ADVANCED OPTICAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Ziyi Hu, Ryan O'Neill, Rostyslav Lesyuk, Christian Klinke
Summary: Due to spatial confinement, two-dimensional metal chalcogenides show extraordinary optical response and carrier transport ability. Colloidal chemistry developments allow the synthesis of various ultrathin colloidal nanoplatelets with specific properties. By altering experimental conditions and applying capping ligands, the dimensionality and optical properties of colloidal metal chalcogenide crystals can be accurately tuned for potential applications in photovoltaics, optoelectronics, and spintronics.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Ivo Tanghe, Justinas Butkus, Kai Chen, Ronnie R. Tamming, Shalini Singh, Yera Ussembayev, Kristiaan Neyts, Dries van Thourhout, Justin M. Hodgkiss, Pieter Geiregat
Summary: The refractive index change of 2D semiconductors is crucial for realizing various photonic devices. By utilizing femtosecond interferometry and effective medium algorithm, the time-dependent refractive index of colloidal 2D materials can be measured and calculated, showing significant phase modulation due to excitonic features.
Article
Chemistry, Physical
Mingyuan Xie, Yuchen Zhu, Rongming Wang, Jianjun Tian
Summary: High-quality CsPbI3 CQWs were successfully synthesized with tunable emission from orange to red, achieving a high photoluminescence quantum yield and narrow emission bandwidth. The CIE coordinates meet the requirement of the Rec. 2020 standard.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Negar Gheshlaghi, Sina Foroutan-Barenji, Onur Erdem, Yemliha Altintas, Farzan Shabani, Muhammad Hamza Humayun, Hilmi Volkan Demir
Summary: The study presents the first account of self-resonant fully colloidal mu-lasers made from colloidal quantum well (CQW) solution. A deep patterning technique is developed to fabricate well-defined high aspect-ratio on-chip CQW resonators, allowing for in-plane lasing with tight optical confinement. The method is also successfully applied to various nanoparticles without affecting their physical and chemical properties.
Article
Chemistry, Multidisciplinary
Ying Tang, Qilin Qin, Hongyu Yang, Shengnan Feng, Chunfeng Zhang, Jiayu Zhang, Min Xiao, Xiaoyong Wang
Summary: This study demonstrates the ability to decrease the Auger decay and radiative rates in semiconductor nanocrystals by applying external electric fields. The decrease in the Auger rate is attributed to enhanced exciton-exciton repulsion, while the decrease in the radiative rate is attributed to weakened electron-hole exchange interaction. These findings highlight the potential of using external electric fields as a post-synthetic approach to manipulate the exciton recombination dynamics in semiconductor nanocrystals.
Article
Physics, Condensed Matter
Spyridon G. Kosionis, Emmanuel Paspalakis
Summary: The study theoretically analyzes the energy absorption rate spectrum of a coupled nanostructure composed of a semiconductor quantum dot and a spherical metal nanoparticle interacting with a linearly polarized electromagnetic field. The results reveal three regular peaks on the SQD spectrum and three Fano-type resonance line shapes on the MNP spectrum. Increasing the absolute value of the biexciton energy shift leads to a larger distance between these peaks. These findings have potential applications in nanotechnology.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Alexander M. Smirnov, Anastasia D. Golinskaya, Vladimir N. Mantsevich, Maria Kozlova, Kseniia V. Ezhova, Bedil M. Saidzhonov, Roman B. Vasiliev, Vladimir S. Dneprovskii
Summary: Experimental investigations were conducted on the transient absorption of colloidal heterostructured CdSe/CdS nanoplatelets under high-intensity nanosecond laser pulses, revealing a strong dependence on nanoplatelets concentration and pump intensities. Nonlinear transmission changes in nanoplatelets solutions were explained by various factors, and the identification of conditions for optical gain in colloidal solutions was a significant result.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Itay Meir, Faris Horani, Shahar Zuri, Efrat Lifshitz
Summary: A thorough study presents the influence of surfactants' dielectric screening on the exciton energy and exciton-phonon coupling in CdSe and CdSe/CdS colloidal quantum dots and nanoplatelets. The study reveals the temperature dependence of the exciton-phonon interactions and the anomalous effect on the exciton energy at approximately 250 K, coinciding with the melting point of the surfactants. The study also uncovers the tuning of the optical phonon frequency and the coupling with the phonon mode of the shell in different conditions.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Physical
Haihua Zhang, Jiannian Yao, Yongan Yang, Hongbing Fu
Summary: This study presents alloyed Mn:(PEA)(2)PbBr4 2D perovskite quantum wells, achieving efficient dual-color emissions with high energy transfer efficiency and solid-state photoluminescence quantum yield. Excitation and temperature are shown as two efficient approaches to precisely modulate color-tunable dual emissions with excellent reversibility, indicating possible applications in photo-/thermal switchable markers and efficient thermometers for biomedical imaging and diagnostic investigations.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Goutam Ghosh, Kritiman Marjit, Srijon Ghosh, Amitava Patra
Summary: We investigate the fast hot-carrier (HC) relaxation and Auger recombination (AR) rates in hexapod CsPbBr3 NCs using ultrafast transient absorption (TA) spectroscopy. Our results show that hexapod CsPbBr3 has a prolonged HC cooling time and bi-exciton lifetime compared to cubic CsPbBr3. By employing the electron-phonon coupling model, we confirm the slower HC relaxation rate in hexapod CsPbBr3, suggesting a delayed decay of longitudinal optical (LO) phonons. We demonstrate that delocalization of charge carriers in shallow trap states leads to reduced overlap of electron and hole wave functions and suppresses the bi-exciton AR rate.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Hoang Long Nguyen, Thanh Nhut Do, Emek G. Durmusoglu, Merve Izmir, Ritabrata Sarkar, Sougata Pal, Oleg V. Prezhdo, Hilmi Volkan Demir, Howe-Siang Tan
Summary: In this study, the ultrafast spectral diffusion, vibronic dynamics, and energy relaxation of CdSe colloidal quantum wells (CQWs) at room temperature were measured using two-dimensional electronic spectroscopy (2DES). The energy relaxation from light-hole (LH) excitons to heavy-hole (HH) excitons was observed to occur within a time scale of approximately 210 fs. Equilibration dynamics between the spectroscopically accessible HH excitonic state and a dark state were found to take place within a time scale of approximately 160 fs. The spectral diffusion dynamics in HH excitons were analyzed using center line slope analysis, revealing a sub-200 fs decay and oscillatory features resolved at 4 and 25 meV. Quantum calculations were performed to replicate and explain the observed dynamics. The 4 meV mode was found to be in the near-critically damped regime and may mediate the transition between the bright and dark HH excitons. These findings demonstrate the capability of 2DES to comprehensively and detailedly characterize the ultrafast spectral properties in CQWs and similar nanomaterials.
Article
Chemistry, Physical
Wenli Guo, Jialun Tang, Guofeng Zhang, Bin Li, Changgang Yang, Ruiyun Chen, Chengbing Qin, Jianyong Hu, Haizheng Zhong, Liantuan Xiao, Suotang Jia
Summary: The study shows that a smooth core/shell interface has different effects on the photoluminescence blinking and biexciton Auger recombination in single colloidal quantum dots. In some QDs, a smooth interface can reduce photoluminescence blinking, while in others it may increase photoluminescence blinking activity.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)