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Ha ST, Lassalle E, Liang X, Do TTH, Foo I, Shendre S, Durmusoglu EG, Valuckas V, Adhikary S, Paniagua-Dominguez R, Demir HV, Kuznetsov AI. Dual-Resonance Nanostructures for Color Downconversion of Colloidal Quantum Emitters. NANO LETTERS 2023; 23:11802-11808. [PMID: 38085099 DOI: 10.1021/acs.nanolett.3c03786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
We present a dual-resonance nanostructure made of a titanium dioxide (TiO2) subwavelength grating to enhance the color downconversion efficiency of CdxZn1-xSeyS1-y colloidal quantum dots (QDs) emitting at ∼530 nm when excited with a blue light at ∼460 nm. A large mode volume can be created within the QD layer by the hybridization of the grating resonances and waveguide modes, resulting in large absorption and emission enhancements. Particularly, we achieved polarized light emission with a maximum photoluminescence enhancement of ∼140 times at a specific angular direction and a total enhancement of ∼34 times within a 0.55 numerical aperture (NA) of the collecting objective. The enhancement encompasses absorption, Purcell and outcoupling enhancements. We achieved a total absorption of 35% for green QDs with a remarkably thin color conversion layer of ∼400 nm. This work provides a guideline for designing large-volume cavities for absorption/fluorescence enhancement in microLED display, detector, or photovoltaic applications.
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Affiliation(s)
- Son Tung Ha
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Emmanuel Lassalle
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Xiao Liang
- LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, The Photonics Institute, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Thi Thu Ha Do
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Ian Foo
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Sushant Shendre
- LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, The Photonics Institute, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Emek G Durmusoglu
- LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, The Photonics Institute, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Vytautas Valuckas
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Sourav Adhikary
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Ramon Paniagua-Dominguez
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Hilmi Volkan Demir
- LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, The Photonics Institute, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- UNAM─Institute of Materials Science and Nanotechnology, The National Nanotechnology Research Center, Department of Electrical and Electronics Engineering, Department of Physics, Bilkent University, Bilkent, Ankara 06800, Turkey
| | - Arseniy I Kuznetsov
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
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Chiang WH, Chang YH, Lin CC, Kuo HC, Lin GR, Huang JJ. Effect of radiative and nonradiative energy transfer processes of light-emitting diodes combined with quantum dots for visible light communication. NANOSCALE RESEARCH LETTERS 2023; 18:29. [PMID: 36862206 DOI: 10.1186/s11671-023-03812-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/22/2023] [Indexed: 05/24/2023]
Abstract
Though light-emitting diodes (LEDs) combined with various color conversion techniques have been widely explored for VLC (visible light communication), E-O (electro-optical) frequency responses of devices with quantum dots (QDs) embedded within the nanoholes have rarely been addressed. Here we propose LEDs with embedded photonic crystal (PhC) nanohole patterns and green light QDs for studying small-signal E-O frequency bandwidths and large signal on-off keying E-O responses. We observe that the E-O modulation quality of PhC LEDs with QDs is better than a conventional LED with QDs when the overall blue mixed with green light output signal is considered. However, the optical response of only QD converted green light shows a contradictory result. The slower E-O conversion response is attributed to multi-path green light generation from both radiative and nonradiative energy transfer processes for QDs coated on the PhC LEDs.
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Affiliation(s)
- Wen-Hao Chiang
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10639, Taiwan
| | - Yu-Hsiang Chang
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10639, Taiwan
| | - Chien-Chung Lin
- Department of Electrical Engineering, National Taiwan University, Taipei, 10639, Taiwan
| | - Hao-Chung Kuo
- Department of Photonics and Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineer, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Gong-Ru Lin
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10639, Taiwan
| | - Jian-Jang Huang
- Department of Electrical Engineering, National Taiwan University, Taipei, 10639, Taiwan.
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Hyun BR, Sher CW, Chang YW, Lin Y, Liu Z, Kuo HC. Dual Role of Quantum Dots as Color Conversion Layer and Suppression of Input Light for Full-Color Micro-LED Displays. J Phys Chem Lett 2021; 12:6946-6954. [PMID: 34283594 DOI: 10.1021/acs.jpclett.1c00321] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In micro-light-emitting diode (micro-LED) displays with color-conversion layers, a facile and efficient technology getting rid of the use of the color filters leads to a big technical leap in cost-effective fabrication. In this study, it is demonstrated that quantum dot (QD) color conversion layers can significantly suppress residual blue excitation light because of the high extinction coefficients of QDs, ∼0.1% transmittance of blue light for green and red core/shell CdSe/ZnS QD film with thickness of less than 17 μm, and produce green and red colors. Incorporation of TiO2 nanoparticles into QD solutions enhances more than 10% of the luminous intensity by the scattering effect. It is found that the suppression of QD reabsorption is essential to achieve a high color-conversion efficiency. Our results provide a clear path to a cost-effective fabrication of QD conversion layer micro-LED displays over the full range of their applications.
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Affiliation(s)
- Byung-Ryool Hyun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China 518055
| | - Chin-Wei Sher
- Fok Ying Tung Research Institute, Hong Kong University of Science and Technology, Guangzhou, China 511458
| | - Yu-Wei Chang
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan 30010
| | - Yonghong Lin
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China 518055
| | - Zhaojun Liu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China 518055
| | - Hao-Chung Kuo
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan 30010
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Liu Z, Lin CH, Hyun BR, Sher CW, Lv Z, Luo B, Jiang F, Wu T, Ho CH, Kuo HC, He JH. Micro-light-emitting diodes with quantum dots in display technology. LIGHT, SCIENCE & APPLICATIONS 2020; 9:83. [PMID: 32411368 PMCID: PMC7214519 DOI: 10.1038/s41377-020-0268-1] [Citation(s) in RCA: 128] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 02/04/2020] [Accepted: 02/19/2020] [Indexed: 05/03/2023]
Abstract
Micro-light-emitting diodes (μ-LEDs) are regarded as the cornerstone of next-generation display technology to meet the personalised demands of advanced applications, such as mobile phones, wearable watches, virtual/augmented reality, micro-projectors and ultrahigh-definition TVs. However, as the LED chip size shrinks to below 20 μm, conventional phosphor colour conversion cannot present sufficient luminance and yield to support high-resolution displays due to the low absorption cross-section. The emergence of quantum dot (QD) materials is expected to fill this gap due to their remarkable photoluminescence, narrow bandwidth emission, colour tuneability, high quantum yield and nanoscale size, providing a powerful full-colour solution for μ-LED displays. Here, we comprehensively review the latest progress concerning the implementation of μ-LEDs and QDs in display technology, including μ-LED design and fabrication, large-scale μ-LED transfer and QD full-colour strategy. Outlooks on QD stability, patterning and deposition and challenges of μ-LED displays are also provided. Finally, we discuss the advanced applications of QD-based μ-LED displays, showing the bright future of this technology.
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Affiliation(s)
- Zhaojun Liu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chun-Ho Lin
- School of Materials Science and Engineering, University of New South Wales (UNSW), 2052 Sydney, NSW Australia
| | - Byung-Ryool Hyun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Chin-Wei Sher
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong, China
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, Chiao Tung University, 30010 Hsinchu, Taiwan China
| | - Zhijian Lv
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Bingqing Luo
- School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen, China
| | - Fulong Jiang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Tom Wu
- School of Materials Science and Engineering, University of New South Wales (UNSW), 2052 Sydney, NSW Australia
| | | | - Hao-Chung Kuo
- Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, Chiao Tung University, 30010 Hsinchu, Taiwan China
| | - Jr-Hau He
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
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Wang YT, Wu RN, Ni CC, Lu CC, Cai CJ, Tse WF, Chang WY, Kuo Y, Kiang YW, Yang CC. Important role of surface plasmon coupling with the quantum wells in a surface plasmon enhanced color-converting structure of colloidal quantum dots on quantum wells. OPTICS EXPRESS 2020; 28:13352-13367. [PMID: 32403812 DOI: 10.1364/oe.390478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/11/2020] [Indexed: 06/11/2023]
Abstract
To improve the color-conversion efficiency based on a quantum-well (QW) light-emitting diode (LED), a more energy-saving strategy is needed to increase the energy transfer efficiency from the electrical input power of the LED into the emission of over-coated color-converter, not just from LED emission into converted light. In this regard, the efficiency of energy transfer of any mechanism from LED QW into the color-converter is an important issue. By overlaying blue-emitting QW structures and GaN templates with both deposited metal nanoparticles (DMNPs) and color-converting quantum dot (QD) linked synthesized metal nanoparticles (SMNPs) of different localized surface plasmon (LSP) resonance wavelengths for producing multiple surface plasmon (SP) coupling mechanisms with the QW and QD, we study the enhancement variations of their internal quantum efficiencies and photoluminescence decay times. By comparing the QD emission efficiencies between the samples with and without QW, one can observe the advantageous effect of QW coupling with LSP resonances on QD emission efficiency. Also, with the LSP resonance wavelengths of both DMNPs and SMNPs close to the QW emission wavelength for producing strong SP coupling with the QW and hence QD absorption, a higher QD emission or color-conversion efficiency can be obtained.
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Chen F, Wang LJ, Li X, Deng ZB, Teng F, Tang AW. Solution-processed double-layered hole transport layers for highly-efficient cadmium-free quantum-dot light-emitting diodes. OPTICS EXPRESS 2020; 28:6134-6145. [PMID: 32225869 DOI: 10.1364/oe.386276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/02/2020] [Indexed: 06/10/2023]
Abstract
The search for heavy-metal-free quantum-dot light-emitting diodes (QD-LEDs) has greatly intensified in the past few years because device performance still falls behind that of CdSe-based QD-LEDs. Apart from the effects of nanostructures of the emitting materials, the unbalanced charge injection and transport severely affects the performance of heavy-metal-free QD-LEDs. In this work, we presented solution-processed double hole transport layers (HTLs) for improving the device performance of heavy-metal-free Cu-In-Zn-S(CIZS)/ZnS-based QD-LEDs, in which N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (TPD) as an interlayer was incorporated between the emitting layer and the HTL. Through optimizing the thickness of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenyl-amine (TFB) and TPD layers, a maximum external quantum efficiency (ηEQE) of 3.87% and a current efficiency of 9.20 cd A-1 were achieved in the solution-processed QD-LEDs with double-layered TFB/TPD as the HTLs, which were higher than those of the devices with pristine TFB, TPD and TFB:TPD blended layers. The performance enhancement could be attributed to the synergistic effects of the reduction of the hole injection barrier, the increase of the hole mobility and suppressed charge transfer between the HTL and the emitting layer. Furthermore, the best ηEQE of 5.61% with a mean ηEQE of 4.44 ± 0.73% was realized in the Cu-In-Zn-S-based QD-LEDs by varying the annealing temperature of TPD layer due to the more balanced charge injection and transport as well as smooth surface of TPD layer.
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Chang WY, Kuo Y, Kiang YW, Yang CC. Simulation study on light color conversion enhancement through surface plasmon coupling. OPTICS EXPRESS 2019; 27:A629-A642. [PMID: 31252843 DOI: 10.1364/oe.27.00a629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
A theoretical model together with a numerical algorithm of surface plasmon (SP) coupling are built for simulating SP-enhanced light color conversion from a shorter-wavelength radiating dipole (representing a quantum well - QW) into a longer-wavelength one (representing a quantum dot - QD) through QD absorption at the shorter wavelength. An Ag nanoparticle (NP) located between the two dipoles is designed for producing strong SP couplings simultaneously at the two wavelengths. At the QW emission wavelength, SP couplings with the QW and QD dipoles lead to the energy transfer from the QW into the QD and hence the absorption enhancement of the QD. At the QD emission wavelength, SP coupling with the excited QD dipole results in the enhancement of QD emission efficiency. The combination of the SP-induced effects at the two wavelengths leads to the increase of overall color conversion efficiency. The color conversion efficiencies in using Ag NPs of different geometries or SP resonance behaviors for producing different QD absorption and emission enhancement levels are compared.
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Weng Y, Chen G, Zhou X, Yan Q, Guo T, Zhang Y. Design and fabrication of bi-functional TiO 2/Al 2O 3 nanolaminates with selected light extraction and reliable moisture vapor barrier performance. NANOTECHNOLOGY 2019; 30:085702. [PMID: 30523924 DOI: 10.1088/1361-6528/aaf4e1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Bi-functional thin film with both selected light extraction and reliable moisture vapor barrier was proposed for simultaneous light management and encapsulation in the fields of lighting and display. Atomic layer deposition (ALD) was employed to obtain TiO2 and Al2O3 films with high uniformity, forming distributed Bragg reflector (DBR) structure. The DBRs exhibited excellent and tunable optical properties, as well as reliable moisture barrier performance. With increasing the DBR layers, the transmittances decreased obviously. The transmittance in the blue light region was as low as 0.66% for DBR with 6.5 pairs and the water vapor transmission rates value was 3.06 × 10-5 g m-2 d-1 for DBR with 4.5 pairs. These DBRs were integrated in the red quantum dot (QD) based color converters excited by blue LED, enabling an obvious increase in red emission and a strong decrease in blue light transmittance. Furthermore, these DBRs can prolong the lifetime of QDs evidently by isolating the QDs from the moisture (oxygen) vapor. These results highlight the potentials for the exploitation of DBRs fabricated using ALD in the application of lighting and display devices based on QD photoluminescence and electroluminescence.
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Affiliation(s)
- Yalian Weng
- College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002, People's Republic of China
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Lin CH, Chiang HC, Wang YT, Yao YF, Chen CC, Tse WF, Wu RN, Chang WY, Kuo Y, Kiang YW, Yang CC. Efficiency enhancement of light color conversion through surface plasmon coupling. OPTICS EXPRESS 2018; 26:23629-23640. [PMID: 30184861 DOI: 10.1364/oe.26.023629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 08/21/2018] [Indexed: 06/08/2023]
Abstract
The efficiency enhancement of light color conversion from blue quantum well (QW) emission into red quantum dot (QD) emission through surface plasmon (SP) coupling by coating CdSe/ZnS QDs on the top of an InGaN/GaN QW light-emitting diode (LED) is demonstrated. Ag nanoparticles (NPs) are fabricated within a transparent conductive Ga-doped ZnO interlayer to induce localized surface plasmon (LSP) resonance for simultaneously coupling with the QWs and QDs. Such a coupling process generates three enhancement effects, including QW emission, QD absorption at the QW emission wavelength, and QD emission, leading to an overall enhancement effect of QD emission intensity. An Ag NP geometry for inducing an LSP resonance peak around the middle between the QW and QD emission wavelengths results in the optimized condition for maximizing QD emission enhancement. Internal quantum efficiency and photoluminescence (PL) decay time measurements are performed to show consistent results with LED performance characterizations, even though the QD absorption of PL excitation laser may mix with the SP-induced QD absorption enhancement effect in PL measurement.
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