1
|
Elisa M, Sava BA, Eftimie M, Nicoara AI, Vasiliu IC, Rusu MI, Bartha C, Enculescu M, Kuncser AC, Oane M, Aguado CE, López-Torres D. A Nanocomposite Sol-Gel Film Based on PbS Quantum Dots Embedded into an Amorphous Host Inorganic Matrix. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7105. [PMID: 38005035 PMCID: PMC10672267 DOI: 10.3390/ma16227105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023]
Abstract
In this study, a sol-gel film based on lead sulfide (PbS) quantum dots incorporated into a host network was synthesized as a special nanostructured composite material with potential applications in temperature sensor systems. This work dealt with the optical, structural, and morphological properties of a representative PbS quantum dot (QD)-containing thin film belonging to the Al2O3-SiO2-P2O5 system. The film was prepared using the sol-gel method combined with the spin coating technique, starting from a precursor solution containing a suspension of PbS QDs in toluene with a narrow size distribution and coated on a glass substrate in a multilayer process, followed by annealing of each deposited layer. The size (approximately 10 nm) of the lead sulfide nanocrystallites was validated by XRD and by the quantum confinement effect based on the band gap value and by TEM results. The photoluminescence peak of 1505 nm was very close to that of the precursor PbS QD solution, which demonstrated that the synthesis route of the film preserved the optical emission characteristic of the PbS QDs. The photoluminescence of the lead sulfide QD-containing film in the near infrared domain demonstrates that this material is a promising candidate for future sensing applications in temperature monitoring.
Collapse
Affiliation(s)
- Mihail Elisa
- National Institute of R&D for Optoelectronics-INOE 2000, 409 Atomistilor Str., 077125 Magurele, Romania; (M.E.); (I.C.V.); (M.I.R.)
| | - Bogdan Alexandru Sava
- National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Str., 077125 Magurele, Romania;
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1 Gheorghe Polizu Str., 011061 Bucharest, Romania
| | - Mihai Eftimie
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1 Gheorghe Polizu Str., 011061 Bucharest, Romania
| | - Adrian Ionut Nicoara
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1 Gheorghe Polizu Str., 011061 Bucharest, Romania
| | - Ileana Cristina Vasiliu
- National Institute of R&D for Optoelectronics-INOE 2000, 409 Atomistilor Str., 077125 Magurele, Romania; (M.E.); (I.C.V.); (M.I.R.)
| | - Madalin Ion Rusu
- National Institute of R&D for Optoelectronics-INOE 2000, 409 Atomistilor Str., 077125 Magurele, Romania; (M.E.); (I.C.V.); (M.I.R.)
| | - Cristina Bartha
- National Institute of Materials Physics, Atomistilor 405 A, 077125 Magurele, Romania; (C.B.); (M.E.); (A.C.K.)
| | - Monica Enculescu
- National Institute of Materials Physics, Atomistilor 405 A, 077125 Magurele, Romania; (C.B.); (M.E.); (A.C.K.)
| | - Andrei Cristian Kuncser
- National Institute of Materials Physics, Atomistilor 405 A, 077125 Magurele, Romania; (C.B.); (M.E.); (A.C.K.)
| | - Mihai Oane
- National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Str., 077125 Magurele, Romania;
| | - César Elosúa Aguado
- Department of Electrical, Electronic and Communications Engineering, Public University of Navarra, E-31006 Pamplona, Spain; (C.E.A.); (D.L.-T.)
- Institute of Smart Cities (ISC), Public University of Navarra, E-31006 Pamplona, Spain
| | - Diego López-Torres
- Department of Electrical, Electronic and Communications Engineering, Public University of Navarra, E-31006 Pamplona, Spain; (C.E.A.); (D.L.-T.)
| |
Collapse
|
2
|
Karadza B, Van Avermaet H, Mingabudinova L, Hens Z, Meuret Y. Comparison of different RGB InP-quantum-dot-on-chip LED configurations. OPTICS EXPRESS 2022; 30:43522-43533. [PMID: 36523048 DOI: 10.1364/oe.476135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
InP/ZnSe/ZnS quantum dots (QDs) offer a cadmium-free solution to make white LEDs with a narrow blue, green and red emission peak. Such LEDs are required for display and lighting applications with high color gamut. An important phenomenon that hampers the efficiency of such quantum-dot-on-chip LEDs is re-absorption of already converted light by the QDs. Proposed solutions to remedy this effect often rely on complex or cost-ineffective manufacturing methods. In this work, four different RGB QD-on-chip LED package configurations are investigated that can be fabricated with a simple cavity encapsulation method. Using accurate optical simulations, the impact of QD re-absorption on the overall luminous efficacy of the light source is analyzed for these four configurations as a function of the photo-luminescent quantum yield (PLQY) of the QDs. The simulation results are validated by implementing these configurations in QD-on-chip LEDs using a single set of red and green emitting InP/ZnSe/ZnS QDs. In this way, the benefits are demonstrated of adding volume scattering particles or a hemispherical extraction dome to the LED package. The best configuration in terms of luminous efficacy, however, is one where the red QDs are deposited in the recycling cavity, while the green QDs are incorporated in the extraction dome. Using this configuration with green and red InP/ZnSe/ZnS QDs with a PLQY of 75% and 65% respectively, luminous efficacy of 102 lm/W was realized for white light with a CCT of 3000 K.
Collapse
|
3
|
A Nonstandard Path Integral Model for Curved Surface Analysis. ENERGIES 2022. [DOI: 10.3390/en15124322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The nonstandard finite-difference time-domain (NS-FDTD) method is implemented in the differential form on orthogonal grids, hence the benefit of opting for very fine resolutions in order to accurately treat curved surfaces in real-world applications, which indisputably increases the overall computational burden. In particular, these issues can hinder the electromagnetic design of structures with electrically-large size, such as aircrafts. To alleviate this shortcoming, a nonstandard path integral (PI) model for the NS-FDTD method is proposed in this paper, based on the fact that the PI form of Maxwell’s equations is fairly more suitable to treat objects with smooth surfaces than the differential form. The proposed concept uses a pair of basic and complementary path integrals for H-node calculations. Moreover, to attain the desired accuracy level, compared to the NS-FDTD method on square grids, the two path integrals are combined via a set of optimization parameters, determined from the dispersion equation of the PI formula. Through the latter, numerical simulations verify that the new PI model has almost the same modeling precision as the NS-FDTD technique. The featured methodology is applied to several realistic curved structures, which promptly substantiates that the combined use of the featured PI scheme greatly improves the NS-FDTD competences in the case of arbitrarily-shaped objects, modeled by means of coarse orthogonal grids.
Collapse
|
4
|
Xu S, Yang T, Lin J, Shen Q, Li J, Ye Y, Wang L, Zhou X, Chen E, Ye Y, Guo T. Precise theoretical model for quantum-dot color conversion. OPTICS EXPRESS 2021; 29:18654-18668. [PMID: 34154118 DOI: 10.1364/oe.425556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/26/2021] [Indexed: 06/13/2023]
Abstract
Quantum-dot color conversion (QDCC) is a promising technique for next-generation full-color displays, such as QD converted organic light-emitting diodes and micro light-emitting diodes. Although present QDCC research has made some progress on the experimental aspect, the optical model and corresponding mathematical expression that can lay an indispensable foundation for QDCC have not been reported yet. In this paper, we present a theoretical model for precisely describing the complete optical behavior of QDCC, including optical transmission, scattering, absorption, and conversion process. A key parameter of QDCC, called dosage factor (DoF), is defined to quantitatively express the total consumption of QDs that can be calculated as the product of film thickness and QD concentration. Theoretical relations are established between DoF and three key performance indicators of QDCC, namely the light conversion efficiency (LCE), blue light transmittance (BLT), and optical density (OD). The maximum LCE value can be predicted based on this theoretical model, as well as the relationship between the slope of the OD curve and the molar absorption coefficient of blue light. This theoretical model is verified by both simulation and experiment. Results show that the simulation and experimental data highly match the theoretical model, and the goodness of fit reaches higher than 96% for LCE, BLT, and OD. Based on this, the optimal interval of DoF is recommended that provides key guiding significance to the QDCC related experiment.
Collapse
|
5
|
Study of the Optical Properties of Multi-Particle Phosphors by the FDTD and Ray Tracing Combined Method. PHOTONICS 2020. [DOI: 10.3390/photonics7040126] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is well known that the optical properties of multi-particle phosphor are crucial to the light performance of white light-emitting diodes (LEDs). Note that the optical properties including scattering or absorption properties for a single particle are easy to be calculated. However, due to the large computation considering the complicated re-scattering and re-absorption, it is difficult to calculate the scattering behaviors of the multi-particles. A common method to reduce the computation, which can cause unknown deviations, is to replace the multi-particle scattering properties by using the average scattering data of single particles. In this work, a cluster of multi-phosphor particles are directly simulated by the finite-difference time-domain (FDTD) method. The total scattering data of the cluster was processed as a bulk scattering parameter and imported to the Monte-Carlo ray-tracing (RT) method to realize a large-scale multi-particle scattering calculation. A polynomial mathematical model was built according to the multi-particle scattering data. An experiment was carried out for verifying the accuracy of the method in this work. The mean absolute percentages of the previous method are 1.68, 2.06, and 1.22 times larger than the multi-particle method compared with the experimental curves, respectively.
Collapse
|
6
|
Assessment of Crystalline Materials for Solid State Lighting Applications: Beyond the Rare Earth Elements. CRYSTALS 2020. [DOI: 10.3390/cryst10070559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In everyday life, we are continually exposed to different lighting systems, from the home interior to car lights and from public lighting to displays. The basic emission principles on which they are based range from the old incandescent lamps to the well-established compact fluorescent lamps (CFL) and to the more modern Light Emitting Diode (LEDs) that are dominating the actual market and also promise greater development in the coming years. In the LED technology, the key point is the electroluminescence material, but the fundamental role of proper phosphors is sometimes underestimated even when it is essential for an ideal color rendering. In this review, we analyze the main solid-state techniques for lighting applications, paying attention to the fundamental properties of phosphors to be successfully applied. Currently, the most widely used materials are based on rare-earth elements (REEs) whereas Ce:YAG represents the benchmark for white LEDs. However, there are several drawbacks to the REEs’ supply chain and several concerns from an environmental point of view. We analyze these critical issues and review alternative materials that can overcome their use. New compounds with reduced or totally REE free, quantum dots, metal–organic framework, and organic phosphors will be examined with reference to the current state-of-the-art.
Collapse
|
7
|
Bharathi M. V, Roy N, Moharana P, Ghosh K, Paira P. Green synthesis of highly luminescent biotin-conjugated CdSe quantum dots for bioimaging applications. NEW J CHEM 2020. [DOI: 10.1039/d0nj03075a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient green protocol for the synthesis of luminescent biotin-conjugated CdSe quantum dots has been developed for bioimaging applications.
Collapse
Affiliation(s)
- Vijaya Bharathi M.
- School of Electronic Engineering (SENSE)
- Vellore Institute of Technology (Chennai campus)
- India
- Department of Chemistry
- School of Advanced Sciences
| | - Nilmadhab Roy
- Department of Chemistry
- School of Advanced Sciences
- Vellore Institute of Technology University
- Vellore 632014
- India
| | - Prithvi Moharana
- Department of Chemistry
- School of Advanced Sciences
- Vellore Institute of Technology University
- Vellore 632014
- India
| | - Kaustab Ghosh
- School of Electronic Engineering (SENSE)
- Vellore Institute of Technology (Chennai campus)
- India
| | - Priyankar Paira
- Department of Chemistry
- School of Advanced Sciences
- Vellore Institute of Technology University
- Vellore 632014
- India
| |
Collapse
|
8
|
Yan C, Du X, Li J, Ding X, Li Z, Tang Y. Effect of Excitation Wavelength on Optical Performances of Quantum-Dot-Converted Light-Emitting Diode. NANOMATERIALS 2019; 9:nano9081100. [PMID: 31374836 PMCID: PMC6723292 DOI: 10.3390/nano9081100] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 11/16/2022]
Abstract
Light-emitting diode (LED) combined with quantum dots (QDs) is an important candidate for next-generation high-quality semiconductor devices. However, the effect of the excitation wavelength on their optical performance has not been fully explored. In this study, green and red QDs are applied to LEDs of different excitation wavelengths from 365 to 455 nm. The blue light is recommended for exciting QDs from the perspective of energy utilization. However, QD LEDs excited at 365 nm have unique advantages in eliminating the original peaks from the LED chip. Moreover, the green or red light excited by ultraviolet light has an advantage in colorimetry. Even for the 455 nm LED with the highest QD concentration at 7.0 wt%, the color quality could not compete with the 365 nm LED with the lowest QD concentration at 0.2 wt%. A 117.5% (NTSC1953) color gamut could be obtained by the 365 nm-excited RGB system, which is 32.6% higher than by the 455 nm-excited solution, and this can help expand the color gamut of LED devices. Consequently, this study provides an understanding of the properties of QD-converted LEDs under different wavelength excitations, and offers a general guide to selecting a pumping source for QDs.
Collapse
Affiliation(s)
- Caiman Yan
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China
| | - Xuewei Du
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China
| | - Jiasheng Li
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China
| | - Xinrui Ding
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China
| | - Zongtao Li
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China.
- Foshan Nationstar Optoelectronics Company, Ltd., Foshan 528000, China.
| | - Yong Tang
- Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes, South China University of Technology, Guangzhou 510641, China
| |
Collapse
|
9
|
Li J, Tang Y, Li Z, Ding X, Yu B, Lin L. Largely Enhancing Luminous Efficacy, Color-Conversion Efficiency, and Stability for Quantum-Dot White LEDs Using the Two-Dimensional Hexagonal Pore Structure of SBA-15 Mesoporous Particles. ACS APPLIED MATERIALS & INTERFACES 2019; 11:18808-18816. [PMID: 30997997 DOI: 10.1021/acsami.8b22298] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quantum-dot (QD) white light-emitting diodes (LEDs) are promising for illumination and display applications due to their excellent color quality. Although they have a high quantum yield close to unity, the reabsorption of QD light leads to high conversion loss, significantly reducing the luminous efficacy and stability of QD white LEDs. In this report, SBA-15 mesoporous particles (MPs) with two-dimensional hexagonal pore structures (2D-HPS) are utilized to largely enhance the luminous efficacy and color-conversion efficiency of QD white LEDs in excess of 50%. The reduction in conversion loss also helps QD white LEDs to achieve a lifetime 1.9 times longer than that of LEDs using QD-only composites at harsh aging conditions. Simulation and testing results suggest that the waveguide effect of 2D-HPS helps in reducing the reabsorption loss by constraining the QD light inside the wall of 2D-HPS, decreasing the probability of being captured by QDs inside the hole of 2D-HPS. As such, materials and mechanisms like SBA-15 MPs with 2D-HPS could provide a new path to improve the photon management of QD light, comprehensively enhancing the performances of QD white LEDs.
Collapse
Affiliation(s)
- Jiasheng Li
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology , South China University of Technology , Guangdong 510640 , China
- Foshan Nationstar Optoelectronics Company Ltd. , Foshan 528000 , China
| | - Yong Tang
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology , South China University of Technology , Guangdong 510640 , China
| | - Zongtao Li
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology , South China University of Technology , Guangdong 510640 , China
- Foshan Nationstar Optoelectronics Company Ltd. , Foshan 528000 , China
| | - Xinrui Ding
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology , South China University of Technology , Guangdong 510640 , China
| | - Binhai Yu
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology , South China University of Technology , Guangdong 510640 , China
| | - Liwei Lin
- Department of Mechanical Engineering , University of California , Berkeley , California 94720-5800 , United States
| |
Collapse
|
10
|
Li JS, Tang Y, Li ZT, Cao K, Yan CM, Ding XR. Full spectral optical modeling of quantum-dot-converted elements for light-emitting diodes considering reabsorption and reemission effect. NANOTECHNOLOGY 2018; 29:295707. [PMID: 29715198 DOI: 10.1088/1361-6528/aac1b0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum dots (QDs) have attracted significant attention in light-emitting diode (LED) illumination and display applications, owing to their high quantum yield and unique spectral properties. However, an effective optical model of quantum-dot-converted elements (QDCEs) for (LEDs) that entirely considers the reabsorption and reemission effect is lacking. This suppresses the design of QDCE structures and further investigation of light-extraction/conversion mechanisms in QDCEs. In this paper, we proposed a full spectral optical modeling method for QDCEs packaged in LEDs, entirely considering the reabsorption and reemission effect, and its results are compared with traditional models without reabsorption or reemission. The comparisons indicate that the QDCE absorption loss of QD emission light is a major factor decreasing the radiant efficacy of LEDs, which should be considered when designing QDCE structures. According to the measurements of fabricated LEDs, only calculation results that entirely consider reabsorption and reemission show good agreement with experimental radiant efficacy, spectra, and peak wavelength at the same down-conversion efficiency. Consequently, it is highly expected that QDCE will be modeled considering the reabsorption and reemission events. This study provides a simple and effective modeling method for QDCEs, which shows great potential for their structure designs and fundamental investigations.
Collapse
Affiliation(s)
- Jia-Sheng Li
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong, 510640, People's Republic of China. Foshan Nationstar Optoelectronics Company Ltd, Foshan 528000, People's Republic of China
| | | | | | | | | | | |
Collapse
|
11
|
Li J, Tang Y, Li Z, Ding X, Yu S, Yu B. Improvement in Color-Conversion Efficiency and Stability for Quantum-Dot-Based Light-Emitting Diodes Using a Blue Anti-Transmission Film. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E508. [PMID: 29987191 PMCID: PMC6070891 DOI: 10.3390/nano8070508] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/27/2018] [Accepted: 07/02/2018] [Indexed: 11/17/2022]
Abstract
In this report, a blue anti-transmission film (BATF) has been introduced to improve the color-conversion efficiency (CCE) and the stability of quantum dot (QD) films. The results indicate that the CCE can be increased by as much as 93% using 15 layers of BATFs under the same QD concentration. Therefore, the same CCE can be achieved using BATF-QD hybrid films with a lower QD concentration when compared with standard QD films. The hybrid and QD films with the same CCE of 60% were aged at an environmental temperature of 25°C and with a 10 mA injection current light-emitting diode source. The CCE and luminous efficacy that are gained by the hybrid film increased by 42.8% and 24.5%, respectively, when compared with that gained by the QD film after aging for the same time period of approximately 65 h. In addition, the hybrid film can effectively suppress the red-shift phenomenon of the QD light spectra, as well as an expansion of the full-width at half maximum. Consequently, these BATF-QD hybrid films with excellent optical performance and stability show great potential for illumination and display applications.
Collapse
Affiliation(s)
- Jiasheng Li
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
- Foshan Nationstar Optoelectronics Company Ltd., Foshan 528000, China.
| | - Yong Tang
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
| | - Zongtao Li
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
- Foshan Nationstar Optoelectronics Company Ltd., Foshan 528000, China.
| | - Xinrui Ding
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
| | - Shudong Yu
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
| | - Binhai Yu
- Engineering Research Center of Green Manufacturing for Energy-Saving and New-Energy Technology, South China University of Technology, Guangdong 510640, China.
| |
Collapse
|