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Chen R, Wang Z, Teng Q, Li C, Li J, Zeng L, Zhang R, Huang F, Lei L, Yuan F, Chen D. Binary Host-induced Exciplex Enabled High Color-Rendering Index of 94 for Carbon Quantum Dot-Based White Light-Emitting Diodes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2404485. [PMID: 38872266 DOI: 10.1002/advs.202404485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/25/2024] [Indexed: 06/15/2024]
Abstract
White light-emitting diodes (WLEDs) with high color-rendering index (CRI, >90) are important for backlight displays and solid-state lighting applications. Although the well-developed colloidal quantum dots (QDs) based on heavy metals such as cadmium and lead are promising candidates for WLEDs, the low CRI still remains a significant limitation. In addition, the severe toxicity of heavy metals greatly limits their widespread use. Herein, the study demonstrates low-cost and environmentally friendly carbon quantum dots (CQDs)-based WLEDs that exhibit a high CRI of 94.33, surpassing that of conventional cadmium/lead-containing QD-based WLEDs. This achievement is attained through the employment of a binary host-induced exciplex strategy. The high hole/electron mobility and suitable energy levels of the donor and acceptor give rise to a broadband orange-yellow emission stemming from the exciplex. As the host, the binary exciplex is capable of contributing blue and orange-yellow emission components while efficiently mitigating the aggregation-induced quenching of CQDs. Meanwhile, CQDs effectively address the deep-red emission gap, enabling the realization of CQDs-based WLEDs with high CRI. These WLEDs also exhibit a remarkably low turn-on voltage of 2.8 V, a maximum luminance exceeding 2000 cd m- 2, a correlated color temperature of 4976 K, and Commission Internationale de l'Eclairage coordinates of (0.34, 0.32).
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Affiliation(s)
- Renjing Chen
- College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou, 350117, P. R. China
| | - Zhibin Wang
- College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou, 350117, P. R. China
| | - Qian Teng
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Chenhao Li
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Jinsui Li
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Lingwei Zeng
- School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, 411201, P. R. China
| | - Ruidan Zhang
- College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou, 350117, P. R. China
| | - Feng Huang
- College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou, 350117, P. R. China
| | - Lei Lei
- Institute of Optoelectronic Materials and Devices, China Jiliang University, Hangzhou, 310018, P. R. China
| | - Fanglong Yuan
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Daqin Chen
- College of Physics and Energy, Fujian Normal University, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou, 350117, P. R. China
- Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering, Fuzhou, 350117, P. R. China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage, Fuzhou, 350117, P. R. China
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Wu BS, Lefsrud MG. Photobiology eye safety for horticultural LED lighting: Transmittance performance of eyewear protection using high-irradiant monochromatic LEDs. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2018; 15:133-142. [PMID: 29157183 DOI: 10.1080/15459624.2017.1395959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Light emitting diodes have slowly gained market share as horticultural lighting systems in greenhouses due to their rapid improvement in color performances and light outputs. These advancements have increased the availability of the full spectrum of visible wavelengths and the corresponding irradiance outputs available to plants. However, light emitting diodes owners have limited information on the proper options for personal eyewear protection as the irradiance levels have increased. The objective of this study was to measure the light transmittance performance of 12 eyewear protection including welding goggles, safety goggles, polarized glasses, and sunglasses across the human visible spectrum (380-740 nm) up to an irradiance level of 1500 W·m-2 from high-irradiant light emitting diodes assemblies. Based on the spectral measurements, certain transmitted spectra exhibited spectrum shifts or an alteration in the bimodal distribution which were different than the light emitting diodes spectra, due to the uneven transmittance efficiencies of the glasses. As for the measured transmittance percentages in two experiments, each type of eyewear protection showed distinct transmittance performances, and the performance of the tested eyewear protection was not impacted by irradiance but was dependent on the wavelength. The mean light transmittance was 1.77% for the welding glasses, 13.12% for the polarized glasses, 15.27% for the safety goggles, and 27.65% for the sunglasses. According to these measured results and the spectral weighting exposure limits from the International Electrotechnical Commission 62471 and EU directive 2006/25, consumers and workers using horticultural lighting can select welding goggles or polarized glasses, to limit the possible ocular impact of the high irradiance of monochromatic light in electrical lighting environment. Sunglasses and safety goggles would not be advised as protection, especially if infrared radiation was used.
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Affiliation(s)
- Bo-Sen Wu
- a Department of Bioresource Engineering , McGill University , Montreal , Quebec , Canada
| | - Mark G Lefsrud
- a Department of Bioresource Engineering , McGill University , Montreal , Quebec , Canada
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