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de Souza GF, Magalhães LF, de Souza Carvalho TA, Ferreira DL, Pereira RS, da Cunha TR, Bettini J, Schiavon MA, Vivas MG. Probing the cw-Laser-Induced Fluorescence Enhancement in CsPbBr 3 Nanocrystal Thin Films: An Interplay between Photo and Thermal Activation. ACS APPLIED MATERIALS & INTERFACES 2024; 16:34303-34312. [PMID: 38885089 PMCID: PMC11231974 DOI: 10.1021/acsami.4c03934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 05/30/2024] [Accepted: 06/05/2024] [Indexed: 06/20/2024]
Abstract
Perovskite nanocrystals hold significant promise for a wide range of applications, including solar cells, LEDs, photocatalysts, humidity and temperature sensors, memory devices, and low-cost photodetectors. Such technological potential stems from their exceptional quantum efficiency and charge carrier conduction capability. Nevertheless, the underlying mechanisms of photoexcitation, such as phase segregation, annealing, and ionic diffusion, remain insufficiently understood. In this context, we harnessed hyperspectral fluorescence microspectroscopy to advance our comprehension of fluorescence enhancement triggered by UV continuous-wave (cw) laser irradiation of CsPbBr3 colloidal nanocrystal thin films. Initially, we explored the kinetics of fluorescence enhancement and observed that its efficiency (φph) correlates with the laser power (P), following the relationship φph = 7.7⟨P⟩0.47±0.02. Subsequently, we estimated the local temperature induced by the laser, utilizing the finite-difference method framework, and calculated the activation energy (Ea) required for fluorescence enhancement to occur. Our findings revealed a very low activation energy, Ea ∼ 9 kJ/mol. Moreover, we mapped the fluorescence photoenhancement by spatial scanning and real-time static mode to determine its microscale length. Below a laser power of 60 μW, the photothermal diffusion length exhibited nearly constant values of approximately (22 ± 5) μm, while a significant increase was observed at higher laser power levels. These results were ascribed to the formation of nanocrystal superclusters within the film, which involves the interparticle spacing reduction, creating the so-called quantum dot solid configuration along with laser-induced annealing for higher laser powers.
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Affiliation(s)
- Gabriel Fabrício de Souza
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil
| | - Letícia Ferreira Magalhães
- Grupo de Pesquisa em Química de Materiais, Universidade Federal de São João del-Rei, 36301-160 São João del-Rei, MG, Brazil
| | | | - Diego Lourençoni Ferreira
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil
| | - Richard Silveira Pereira
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil
| | - Thiago Rodrigues da Cunha
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil
| | - Jefferson Bettini
- Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, 13083-970 Campinas, São Paulo, Brazil
| | - Marco Antônio Schiavon
- Grupo de Pesquisa em Química de Materiais, Universidade Federal de São João del-Rei, 36301-160 São João del-Rei, MG, Brazil
| | - Marcelo Gonçalves Vivas
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil
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Muzzillo CP, Ciobanu CV, Moore DT. High-entropy alloy screening for halide perovskites. MATERIALS HORIZONS 2024. [PMID: 38767287 DOI: 10.1039/d4mh00464g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
As the concept of high-entropy alloying (HEA) extends beyond metals, new materials screening methods are needed. Halide perovskites (HP) are a prime case study because greater stability is needed for photovoltaics applications, and there are 322 experimentally observed HP end-members, which leads to more than 1057 potential alloys. We screen HEAHP by first calculating the configurational entropy of 106 equimolar alloys with experimentally observed end-members. To estimate enthalpy at low computational cost, we turn to the delta-lattice parameter approach, a well-known method for predicting III-V alloy miscibility. To generalize the approach for non-cubic crystals, we introduce the parameter of unit cell volume coefficient of variation (UCV), which does a good job of predicting the experimental HP miscibility data. We use plots of entropy stabilization versus UCV to screen promising alloys and identify 102 HEAHP of interest.
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Affiliation(s)
| | | | - David T Moore
- National Renewable Energy Laboratory, Golden, CO, USA.
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Gao R, Kang J. Unusual Band Gap Bowing in CsCd xPb (1-x)Br 3 Alloys Due to a Chemical Mismatch. J Phys Chem Lett 2023; 14:10670-10676. [PMID: 38031666 DOI: 10.1021/acs.jpclett.3c02813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
In this work, the band structure of CsCdxPb1-xBr3 alloys is investigated through first-principles calculations. An unusual upward band gap bowing is revealed, which is consistent with the experimental observations of the blue-shifted gap in Cd doped CsPbBr3. The gap bowing is found to be mainly contributed to by the conduction band minimum. Based on symmetry analysis, it is demonstrated that, at the Pb-rich or Cd-rich regime, the hybridization between the Pb(6p)-driven and Cd(5s)-driven conduction bands is strongly suppressed due to their different symmetries. Such a chemical mismatch leads to an almost independent evolution of the Pb(6p) and Cd(5s) bands. Then, a model of band shrinking and broadening is proposed to explain upward gap bowing. The results highlight the critical role of symmetry in determining the electronic properties of alloys consisting of materials with distinct band edge characters.
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Affiliation(s)
- Rui Gao
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Jun Kang
- Beijing Computational Science Research Center, Beijing 100193, China
- Department of Physics, Beijing Normal University, Beijing 100875, China
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Timkina YA, Tuchin VS, Litvin AP, Ushakova EV, Rogach AL. Ytterbium-Doped Lead-Halide Perovskite Nanocrystals: Synthesis, Near-Infrared Emission, and Open-Source Machine Learning Model for Prediction of Optical Properties. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13040744. [PMID: 36839112 PMCID: PMC9958719 DOI: 10.3390/nano13040744] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 05/12/2023]
Abstract
Lead-halide perovskite nanocrystals are an attractive class of materials since they can be easily fabricated, their optical properties can be tuned all over the visible spectral range, and they possess high emission quantum yields and narrow photoluminescence linewidths. Doping perovskites with lanthanides is one of the ways to widen the spectral range of their emission, making them attractive for further applications. Herein, we summarize the recent progress in the synthesis of ytterbium-doped perovskite nanocrystals in terms of the varying synthesis parameters such as temperature, ligand molar ratio, ytterbium precursor type, and dopant content. We further consider the dependence of morphology (size and ytterbium content) and optical parameters (photoluminescence quantum yield in visible and near-infrared spectral ranges) on the synthesis parameters. The developed open-source code approximates those dependencies as multiple-parameter linear regression and allows us to estimate the value of the photoluminescence quantum yield from the parameters of the perovskite synthesis. Further use and promotion of an open-source database will expand the possibilities of the developed code to predict the synthesis protocols for doped perovskite nanocrystals.
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Affiliation(s)
- Yuliya A. Timkina
- International Research and Education Centre for Physics of Nanostructures, ITMO University, Saint Petersburg 197101, Russia
| | - Vladislav S. Tuchin
- International Research and Education Centre for Physics of Nanostructures, ITMO University, Saint Petersburg 197101, Russia
| | - Aleksandr P. Litvin
- International Research and Education Centre for Physics of Nanostructures, ITMO University, Saint Petersburg 197101, Russia
- Laboratory of Quantum Processes and Measurements, ITMO University, Saint Petersburg 197101, Russia
| | - Elena V. Ushakova
- International Research and Education Centre for Physics of Nanostructures, ITMO University, Saint Petersburg 197101, Russia
- Correspondence:
| | - Andrey L. Rogach
- Department of Materials Science and Engineering & Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong SAR 999077, China
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Litvin AP. Editorial for Special Issue "Luminescent Colloidal Nanocrystals". NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:607. [PMID: 36770568 PMCID: PMC9919542 DOI: 10.3390/nano13030607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
The field of luminescent colloidal nanocrystals and the numerous nanosystems based on them has recently made a rapid breakthrough from initial basic research to real applications and devices [...].
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Skurlov ID, Sokolova AV, Tatarinov DA, Parfenov PS, Kurshanov DA, Ismagilov AO, Koroleva AV, Danilov DV, Zhizhin EV, Mikushev SV, Tcypkin AN, Fedorov AV, Litvin AP. Engineering the Optical Properties of CsPbBr 3 Nanoplatelets through Cd 2+ Doping. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7676. [PMID: 36363269 PMCID: PMC9657966 DOI: 10.3390/ma15217676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 10/29/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
Lead halide perovskite nanoplatelets (NPls) attract significant attention due to their exceptional and tunable optical properties. Doping is a versatile strategy for modifying and improving the optical properties of colloidal nanostructures. However, the protocols for B-site doping have been rarely reported for 2D perovskite NPls. In this work, we investigated the post-synthetic treatment of CsPbBr3 NPls with different Cd2+ sources. We show that the interplay between Cd2+ precursor, NPl concentrations, and ligands determines the kinetics of the doping process. Optimization of the treatment allows for the boosting of linear and nonlinear optical properties of CsPbBr3 NPls via doping or/and surface passivation. At a moderate doping level, both the photoluminescence quantum yield and two-photon absorption cross section increase dramatically. The developed protocols of post-synthetic treatment with Cd2+ facilitate further utilization of perovskite NPls in nonlinear optics, photonics, and lightning.
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Affiliation(s)
- Ivan D. Skurlov
- PhysNano Department, ITMO University, 197101 Saint Petersburg, Russia
| | | | | | - Peter S. Parfenov
- PhysNano Department, ITMO University, 197101 Saint Petersburg, Russia
| | | | - Azat O. Ismagilov
- Laboratory of Quantum Processes and Measurements, ITMO University, 197101 Saint Petersburg, Russia
| | | | - Denis V. Danilov
- Research Park, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Evgeniy V. Zhizhin
- Research Park, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Sergey V. Mikushev
- Research Park, Saint Petersburg State University, 199034 Saint Petersburg, Russia
| | - Anton N. Tcypkin
- Laboratory of Quantum Processes and Measurements, ITMO University, 197101 Saint Petersburg, Russia
| | | | - Aleksandr P. Litvin
- PhysNano Department, ITMO University, 197101 Saint Petersburg, Russia
- Laboratory of Quantum Processes and Measurements, ITMO University, 197101 Saint Petersburg, Russia
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