Article
Materials Science, Multidisciplinary
Maral Vafaie, James Z. Fan, Amin Morteza Najarian, Olivier Ouellette, Laxmi Kishore Sagar, Koen Bertens, Bin Sun, F. Pelayo Garcia de Arquer, Edward H. Sargent
Summary: Efficient ligand exchange route enables large-diameter CQDs to achieve high-efficiency passivation and charge transport, leading to CQD solids with external quantum efficiency greater than 80% at 1,550 nm. This technology has the potential to replace conventional III-V semiconductors and make significant advancements in the field of infrared photodetection.
Article
Chemistry, Multidisciplinary
Taek Joon Kim, Sang-hun Lee, Eunji Lee, Changwon Seo, Jeongyong Kim, Jinsoo Joo
Summary: In this study, the energy band alignments of a heterostructure consisting of MAPbI(3) perovskite sheets and CdSe-ZnS core-shell quantum dot layers were modulated, leading to the emission of far-red interlayer excitons. These excitons exhibited a longer lifetime and strong dipole alignment at the heterojunction. An abnormal behavior of the optical characteristics near the phase transition temperature of MAPbI(3) was observed. Photodetectors based on MAPbI(3)/CdSe-ZnS-QD heterostructures showed increased photocurrent and detectivity compared to MAPbI(3) under interlayer exciton excitation.
Article
Chemistry, Physical
Jonghee Yang, Ashish Sharma, Jung Won Yoon, Watcharaphol Paritmongkol, Seungjin Lee, Hyungju Ahn, Wooseop Lee, Hochan Song, Woo Hyeon Jeong, Bo Ram Lee, Seo-Jin Ko, Mahshid Ahmadi, Edward H. H. Sargent, Hyosung Choi
Summary: Researchers have discovered that randomly-oriented, but closer-packed crystalline structures in bulk heterojunctions (BHJs) can significantly improve charge conduction and restrict diffusion-driven charge transfer process, allowing for ultrafast hole extraction from colloidal quantum dots (CQDs) to BHJs. This finding not only provides key principles to control the packing structures of organic hole transport layers (HTLs), but also opens up a new avenue to enhance optoelectronic performance.
ADVANCED ENERGY MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Nikola Dordevic, Raphael Schwanninger, Maksym Yarema, Stefan Koepfli, Olesya Yarema, Yannick Salamin, Nolan Lassaline, Bojun Cheng, Nuri Yazdani, Alexander Dorodnyy, Yuriy Myronovych Fedoryshyn, Vanessa Wood, Juerg Leuthold
Summary: Efficient and engineered photodetectors using colloidal quantum dots and metasurface enhancement are reported. The photodetectors and photodiodes showed high responsivities and faster responses, thanks to the metasurface design. The metasurface improved the absorption and enabled photogain, resulting in high performance photoconductors and photodiodes.
Article
Chemistry, Multidisciplinary
Taewoo Ko, Samir Kumar, Sanghoon Shin, Dongmin Seo, Sungkyu Seo
Summary: In this study, a novel approach to pattern quantum dot (QD) nanopatterns by electron beam lithography was presented. Colloidal QDs were used without additional modifications, and reliable dot and line patterns with dimensions as small as 140 nm were successfully generated. Additionally, it was shown that using a SiO2 spacer layer on a Au substrate can significantly enhance the fluorescence intensity of QDs.
Article
Chemistry, Multidisciplinary
Jiabin Cui, Somnath Koley, Yossef E. Panfil, Adar Levi, Nir Waiskopf, Sergei Remennik, Meirav Oded, Uri Banin
Summary: By synthesizing the smallest bow-tie nanoantenna and verifying its functionality using single-particle spectroscopy, as well as the formation of an electric-field hotspot at the structure center as predicted by theory, this structure can enhance emission polarization and serve as a photochemical reaction center.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Jianfu Han, Kai Huang, Xuanguang Su, Xiaofei Xiao, Xuemin Gong, Haibin Wang, Juexian Cao
Summary: PbS colloidal quantum dots (CQDs) usually suffer from low carrier mobility due to surface ligand isolation and defects. By combining PbS CQD photodiode with a carbon nanotube (CNT) film field-effect transistor (FET), a transistorized NIR photodetector with high performance and ultrahigh external quantum efficiency (EQE) is achieved.
Article
Nanoscience & Nanotechnology
Ge Mu, Tianyu Rao, Shuo Zhang, Chong Wen, Menglu Chen, Qun Hao, Xin Tang
Summary: This study reports colloidal quantum-dot upconverters with unprecedented performance, achieving a wider range of operation spectral and higher efficiency through optimization of device structure.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Wei Gong, Peng Wang, Wenjie Deng, Xiaobo Zhang, Boxing An, Jingjie Li, Zhaoqing Sun, Dichao Dai, Zekang Liu, Jingzhen Li, Yongzhe Zhang
Summary: This study elucidates that noise current is the predominant factor limiting specific detectivity (D*) in lead sulfide colloidal quantum dot photodetectors. The noise is highly dependent on the trap densities in halide-passivated PbS films and the carriers injected from the Schottky contact. The research findings provide guidance to improve the design of high-performance colloidal quantum dot photodetectors.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Chemistry, Multidisciplinary
Mohamad Insan Nugraha, Indriyati Indriyati, Indah Primadona, Murali Gedda, Gerald Ensang Timuda, Ferry Iskandar, Thomas D. Anthopoulos
Summary: This article reviews recent progress in the use of semiconducting colloidal quantum dots (CQDs) in emerging thin-film thermoelectrics. It outlines the fundamental concepts of thermoelectricity in nanostructured materials, provides an overview of popular synthetic methods for producing CQDs, and discusses their application in thin-film thermoelectric generators (TEGs). The current challenges and future perspectives for enhancing the performance of CQD-based thermoelectric materials are also discussed.
ADVANCED MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Mohamad Insan Nugraha, Indriyati Indriyati, Indah Primadona, Murali Gedda, Gerald Ensang Timuda, Ferry Iskandar, Thomas D. D. Anthopoulos
Summary: Semiconducting colloidal quantum dots (CQDs) are a promising class of thermoelectric materials for future applications. They offer solution processability and scalable manufacturing potential. With their unique low dimensionality, CQDs can be utilized to tune the Seebeck coefficient and thermal conductivity independently, making them suitable for use in thin-film thermoelectric generators (TEGs) operating near room temperature.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Menglu Chen, Xiaomeng Xue, Tianling Qin, Chong Wen, Qun Hao, Xin Tang
Summary: A simple method is introduced to build CQD p-i-n homojunction and inverted n-i-p homojunction photodetectors by preparing various doping type and density CQD inks. It is proven that both normal and inverted homojunctions can achieve specific detectivity D* as high as 10(12)-10(11) Jones and external quantum efficiency near 90% at high operating temperature. The method also works for multiple infrared subranges, such as 1.5 μm for fiber-optical communication, 1.3-1.9 μm for short-wave infrared (SWIR), 1.3-2.5 μm for extend SWIR, and 3.6 μm for mid-wave infrared (MWIR). Applications such as spectrometer and infrared imager are demonstrated.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
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
Justin C. Ondry, John P. Philbin, Michael Lostica, Eran Rabani, A. Paul Alivisatos
Summary: By combining colloidal nanocrystal synthesis, self-assembly, and solution phase epitaxial growth techniques, a method for preparing high-quality single dot thick atomically attached quantum dot superlattices with good uniformity has been developed. The ability to independently tune the size and material of the quantum dot core, shell, QD-QD distance, and matrix material allows for control over various properties depending on specific applications.
Article
Chemistry, Multidisciplinary
Guilherme Almeida, Lara van der Poll, Wiel H. Evers, Emma Szoboszlai, Sander J. W. Vonk, Freddy T. Rabouw, Arjan J. Houtepen
Summary: This study reports on the size-dependent optical properties and biexciton lifetimes of core-only InP colloidal quantum dots. The novel synthesis method allows for the production of a range of monodisperse InP quantum dots with narrow absorption and emission linewidths and high quantum yields.
Article
Chemistry, Physical
Lin Huang, Zikang Ye, Lei Yang, Jiongzhao Li, Haiyan Qin, Xiaogang Peng
Summary: The study proposes localization of exciton wavefunctions away from the inorganic-organic interface to synthesize colloidal spheroidal quantum dots with ultranarrow photoluminescence peak width. By controlling the synthetic process of alloy QDs, regular and uniform CdxZn1-xSe and CdxZn1-xSe/ZnSe/ZnS core/shell QDs have been successfully achieved.
CHEMISTRY OF MATERIALS
(2021)
Article
Physics, Applied
Yong He, Shupei Lin, Hadrien Marc Louis Robert, Hong Li, Pu Zhang, Marek Piliarik, Xue-Wen Chen
Summary: This paper presents a theoretical framework of multiscale modeling and analysis for interferometric scattering microscopy (iSCAT), exploring the influence of sample shape, illumination, and detection schemes on interference contrast, and providing an explanation for the origin of interference phenomenon. Additionally, it investigates the point spread function of gold nanoparticles in a simplified cell environment.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Xiaoqi Hou, Haiyan Qin, Xiaogang Peng
Summary: Auger recombination is effectively reduced in high-quality quantum dots by enhancing dielectric screening of band-edge carriers with additional ZnS shells. The volume scaling of negative-trion Auger lifetime is achieved with ZnS shells, which can be less than half the volume of QDs without these shells, while also enhancing the biexciton emission quantum yield. The engineering of Auger effects through dielectric screening presents new opportunities for improving emission properties in multicarrier states of quantum dots.
Article
Multidisciplinary Sciences
Zikang Ye, Xing Lin, Na Wang, Jianhai Zhou, Meiyi Zhu, Haiyan Qin, Xiaogang Peng
Summary: Phonon-assisted up-conversion photoluminescence boosts energy by absorbing vibration energy, and colloidal quantum dots can be used as efficient, stable, and cost-effective emitters for up-conversion photoluminescence.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Zhuang Hu, Yufei Shu, Haiyan Qin, Xiaofei Hu, Xiaogang Peng
Summary: The study systematically investigated the responses of high-quality CdSe/CdS core/shell nanocrystals to water and/or oxygen in an ambient environment. It was found that water molecules efficiently accumulated at the nanocrystal-ligand interface could photoreduce the nanocrystals, leading to various photophysical and photochemical phenomena. This research offers a unified basis for studying fundamental properties and designing processing techniques in industry.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Dongdong Chen, Hairui Lei, Chenqi Zhu, Xing Chen, He Tian, Wei Fang, Haiyan Qin, Xiaogang Peng
Summary: In this study, pre-synthesized CdSe/CdS core/shell quantum dots were fused together in solution to form CdS nanoplatelets with multiple embedded CdSe quantum dots. The resulting structure exhibited homogeneous-free optical properties and demonstrated unique and complex excitonic characteristics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Shaojie Liu, Yufei Shu, Meiyi Zhu, Haiyan Qin, Xiaogang Peng
Summary: Most bulk semiconductors show an increase in band-gap energy with decreasing temperature. However, semiconductor quantum dots (QDs) exhibit non-monotonic temperature dependence of the emission energy at low temperatures. This study uses stable and efficient CdSe/CdS/ZnS QDs as a model system to quantitatively explain the origins of the anomalous emission red-shift at temperatures below 40 K. The red-shift is attributed to the temperature-dependent population of band-edge exciton fine levels, enhanced electron-optical phonon coupling due to increasing population of dark excitons, and temperature-dependent electron-acoustic phonon coupling.
Article
Physics, Multidisciplinary
Wancong Li, Qiang Zhou, Pu Zhang, Xue-Wen Chen
Summary: This study proposes the concept of nanoscopic electron reservoir (NER) for direct electro plasmonic and electro-optic modulation. By exploiting the nonclassical effects of conduction electrons, highly electrically susceptible NERs are constructed and achieve pronounced direct electrical tuning of the plasmon mode. Moreover, the electro-plasmonic tuning can be efficiently translated into modulation of optical scattering.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Penglong Ren, Shangming Wei, Weixi Liu, Shupei Lin, Zhaohua Tian, Tailin Huang, Jianwei Tang, Yaocheng Shi, Xue-Wen Chen
Summary: Resonance fluorescence is a promising method for generating indistinguishable single photons and manipulating quantum states in quantum information processing. However, integrating quantum systems on one chip faces challenges such as randomness and scattering background. This study presents an organic-inorganic hybrid integrated quantum photonic platform that enables background-free resonance fluorescence of single molecules with ultrastable lifetime. The platform allows collective alignment of many isolated molecules with the photonic waveguide, enabling on-chip generation and routing of high-quality single photons.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Xiaogang Peng, Liulin Lv, Shaojie Liu, Jiongzhao Li, Haixin Lei, Haiyan Qin
Summary: Zinc-blende CdSe, CdS, and CdSe/CdS core/shell nanocrystals with a structure-matched shape (cube-shaped, edge length <= 30 nm) were synthesized via a universal scheme. These nanocrystals demonstrated novel photoluminescence properties, such as near-unity single exciton and biexciton photoluminescence quantum yields, nonblinking photoluminescence of individual nanocrystals, and stable and narrow photoluminescence full width at half maximum at low temperatures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Optics
Yongjun Meng, Dingxin Huang, Hong Li, Xia Feng, Feng Li, Qianyi Liang, Tianzi Ma, Jiahao Han, Jianwei Tang, Guanying Chen, Xue-Wen Chen
Summary: Stable nanocrystals can be utilized in various fields through plasmonic coupling to achieve high brightness upconversion luminescence, and the saturation of plasmonic enhancement in this phenomenon is demonstrated. Researchers have improved the upconversion luminescence of nanocrystals by optimizing their material properties and surface structures through plasmonic coupling. These findings are of great significance for developing ultrabright upconversion nanomaterials for multiple applications.
Article
Physics, Multidisciplinary
Shupei Lin, Yong He, Delong Feng, Marek Piliarik, Xue-Wen Chen
Summary: We discovered that flat substrates with subnanometer surface undulations show notable speckle patterns when observed with high-sensitivity interference microscopy. We introduced the concept of optical fingerprints and demonstrated their use in position identification and displacement detection.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Hairui Lei, Tenghui Li, Jiongzhao Li, Jie Zhu, Haibing Zhang, Haiyan Qin, Xueqian Kong, Linjun Wang, Xiaogang Peng
Summary: This study investigates facet reconstruction of colloidal wurtzite CdSe/CdS core/shell nanocrystals under typical synthetic conditions and reveals that two sets of facets with specific low-index facets can be reversibly reconstructed by switching the ligand system, indicating their thermodynamic stability. The atomic structures of the low-index facets of wurtzite nanocrystals are diverse, and each facet is paired with a common ligand in the solution. The results suggest that facet-controlled nanocrystals can be synthesized by optimal facet-ligand pairing, enabling the formation of semiconductor nanocrystals with size-dependent properties at an atomic level.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Zhiyuan Cao, Chuyue Li, Yufei Shu, Meiyi Zhu, Bin Su, Haiyan Qin, Xiaogang Peng
Summary: Using CdSe/CdS/ZnS core/shell/shell quantum dots as a model system, time- and potential-resolved spectroelectrochemical measurements were successfully applied to study the mechanisms and kinetics of electrochemiluminescence (ECL) generation. The rate constant of electron injection into a negatively charged quantum dot increased with increasing potential, and the key intermediate for ECL generation was found to be structurally stable and possess slow deionization channels.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Qiang Zhou, Pu Zhang, Xue-Wen Chen
Summary: We report a self-consistent quasinormal mode theory for nanometer scale electromagnetism with incorporation of possible nonlocal and quantum effects through quantum surface responses. Our semianalytical modal analysis enables transparent physical interpretation of the spontaneous emission enhancement of a dipolar emitter as well as the near-field and far-field responses of plane-wave excitations in the nanostructures.
