Article
Chemistry, Multidisciplinary
Menglin Chen, Can Liu, Yulong An, Yan Li, Yunwu Zheng, Hao Tian, Rui Shi, Xiahong He, Xu Lin
Summary: Red, green, and blue CDs were successfully prepared using gallic acid as the raw material through a solvothermal method. The distinct optical features of these CDs are determined by the differences in the size of their sp(2)-domains, which can be controlled by reaction solvents.
NANOSCALE ADVANCES
(2021)
Article
Materials Science, Multidisciplinary
Laureen Moreaud, Janak Prasad, Serges Mazeres, Cecile Marcelot, Clothilde Comby-Zerbino, Rodolphe Antoine, Olivier Heintz, Erik Dujardin
Summary: This study reports a straightforward method for synthesizing red, green, blue and violet emitting AuNCs in pure ethylene glycol with the addition of aniline or indole. By using advanced microscopy, mass spectrometry, and spectroscopy techniques, different sizes of AuNCs were identified and found to emit pure white, blue, green, and violet luminescence. The AuNCs were made water soluble and stable while preserving their photo-physical characteristics by capping them with a thiopegylated ligand shell bearing a carboxylate, amine or biotin. These findings have potential applications in biolabeling, hyperspectral sensing, and display technology.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
Yang Bryan Cao, Daquan Zhang, Qianpeng Zhang, Xiao Qiu, Yu Zhou, Swapnadeep Poddar, Yu Fu, Yudong Zhu, Jin-Feng Liao, Lei Shu, Beitao Ren, Yucheng Ding, Bing Han, Zhubing He, Dai-Bin Kuang, Kefan Wang, Haibo Zeng, Zhiyong Fan
Summary: Cao et al. have successfully fabricated efficient, flexible, and larger-area Red/Green/Blue perovskite light-emitting diodes using all-inorganic metal halide perovskite quantum wires arrays. By utilizing porous alumina membranes as templates and introducing a dual-functional small molecule and a halide vacancy healing agent, stable full-color perovskite LED devices with high external quantum efficiencies have been achieved. This research holds significant importance for next-generation solid state lighting and display technologies.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Qibin Shen, Yanlei Hao, Luying Ma, Xiaoyu Wang
Summary: A comparative study on quantum-dot light-emitting diodes (QLEDs) using time-resolved transient electroluminescence (TREL) revealed that insufficient electron injection at the type II heterojunction affected the performance of B-QLEDs. By applying a polymer as the hole-transporting layer, the efficiency of B-QLEDs improved with an increase in turn-on voltage and the appearance of a transient electroluminescence spike after voltage turn-off.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Yulong An, Xu Lin, Yuxi Zhou, Yan Li, Yunwu Zheng, Chunhua Wu, Kaimeng Xu, Xijuan Chai, Can Liu
Summary: Red, green, and blue carbon dots (RGB CDs) were successfully synthesized with stable optical properties and significant photoluminescence characteristics. A white fluorescent CD solution was prepared by mixing these multicolor fluorescent CDs in appropriate proportions.
Article
Optics
Xin Wang, Ke Tian, Haiyan Zhao, Xiaotong Zhao, Zhi Zhang, Jin Yu, Dejun Liu, Gilberto Brambilla, Pengfei Wang
Summary: This study reports on the challenge of achieving simultaneous blue-red emission in a fiber pumped by a single wavelength source, and investigates the dependence of the blue-to-red upconversion emission ratio on the silica content in Yb3+-Tm3+ codoped fluorosilicate glasses. The results suggest that the probability of the cross-relaxation process 1G4 + 3F2 & RARR;3H6 + 3F4 is key to determining the dominance of the blue or red emissions. This research provides a new platform for variable upconversion luminescence.
Article
Nanoscience & Nanotechnology
Kumar Mallem, Maksym F. Prodanov, Chen Dezhang, Mikita Marus, Chengbin Kang, Sunil B. Shivarudraiah, Valeri V. Vashchenko, Jonathan E. Halpert, Abhishek K. Srivastava
Summary: Solution-processed semiconductor nanocrystals have potential for display and lighting applications due to their tunable emission, saturated colors, and compatibility with flexible substrates. This study successfully synthesized red, green, and blue quantum rods (QRs) and applied them in QR-based light-emitting diodes (QR-LEDs). By embedding a thin poly(methyl methacrylate) (PMMA) electron-blocking layer, charge injection balance and external quantum efficiency were improved. The efficiency roll-off of green and blue QR-LEDs at maximum current density was less than 50%.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Optics
Yunzhou Deng, Feng Peng, Yao Lu, Xitong Zhu, Wangxiao Jin, Jing Qiu, Jiawei Dong, Yanlei Hao, Dawei Di, Yuan Gao, Tulai Sun, Ming Zhang, Feng Liu, Linjun Wang, Lei Ying, Fei Huang, Yizheng Jin
Summary: This study demonstrates high quantum efficiency and excellent stability of green and blue QD-LEDs. By using hole-transport polymers with low electron affinity and reduced energetic disorder, electron leakage at the organic/inorganic interface is successfully eliminated. This research is expected to provide a general strategy for eliminating charge leakage in solution-processed LEDs featuring organic/inorganic interfaces.
Article
Materials Science, Multidisciplinary
Yi-Hua Su, Yan-Cheng Ji, Yu-Ting Huang, Dian Luo, Shun-Wei Liu, Zu-Po Yang, Chin-Wei Lu, Chih-Hao Chang, Hai-Ching Su
Summary: This research demonstrates the enhancement of device efficiencies for deep-red and NIR LECs by integrating efficient blue-green LECs with perovskite color conversion layers. The use of light extraction enhancement technique and diffusive layer further improves the device efficiency. The combinational devices achieve high device efficiencies in the deep-red and NIR wavelength range.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Optics
Yang-Yi Huang, Zong-Han Li, Yi-Cheng Lai, Jun-Chen Chen, Shung-Hsiang Wu, Shaobo Yang, Yang Kuo, Chih-Chung Yang, Ta-Cheng Hsu, Chi-Ling Lee
Summary: The nanoscale-cavity effect significantly increases the emission efficiency of inserted QDs and enhances the FRET efficiency, particularly for radiating dipoles in QWs oriented perpendicular to the sidewalls of the nano-holes. This effect modifies the radiation behavior of light emitters inside a nano-hole through the Purcell effect, resulting in stronger far-field emission.
Article
Chemistry, Inorganic & Nuclear
Manh Trung Tran, Do Quang Trung, Nguyen Tri Tuan, Nguyen Trong Tuan, Nguyen Tu, Nguyen Van Du, Nguyen Duy Hung, Nguyen Van Quang, Tong Thi Hao Tam, Nguyen Duc Trung Kien, Nguyen Minh Hieu, Pham Thanh Huy
Summary: Researchers have successfully synthesized a new green-emitting ZnO:Cu2+ phosphor and applied it in NUV-pumped white LEDs. The phosphor demonstrates high emission intensity and quantum efficiency, making it a promising candidate for NUV-pumped WLED applications.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Physical
Hongling Yu, Heyong Wang, Tiankai Zhang, Chang Yi, Guanhaojie Zheng, Chunyang Yin, Max Karlsson, Jiajun Qin, Jianpu Wang, Xiao-Ke Liu, Feng Gao
Summary: Bandgap tuning through mixing halide anions is an attractive feature for metal halide perovskites, but mixed halide perovskites often exhibit phase segregation under electrical biases. By effectively passivating surface defects, researchers have achieved color-stable blue electroluminescence from mixed bromide/chloride perovskite LEDs, providing new insights into the color instability issue and encouraging further development of high-performance and color-stable blue PeLEDs.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Optics
Zhe Zhuang, Daisuke Iida, Kazuhiro Ohkawa
Summary: The study found that the forward voltage of InGaN-based red/green micro-light-emitting diodes was independent of the dimension, red LEDs exhibited a larger blueshift of peak wavelength and broader full-width at half maximum compared to green LEDs. The 47x47 μm² red LEDs showed an on-wafer external quantum efficiency of 0.36% at the peak wavelength of 626 nm, close to the red primary color defined in the recommendation 2020 standard.
Review
Optics
Xiaoyu Yang, Li Ma, Maotao Yu, Hao-Hsin Chen, Yongqiang Ji, An Hu, Qixuan Zhong, Xiaohan Jia, Yanju Wang, Yuzhuo Zhang, Rui Zhu, Xinqiang Wang, Changjun Lu
Summary: This paper focuses on the lagging progress of blue perovskite light-emitting diodes (PeLEDs) compared to their red and green counterparts. Recent advances and noteworthy strategies in optimizing microstructures, energy landscapes, and charge behaviors of wide-bandgap perovskite emitters are systematically reviewed. The stability of blue perovskite emitters and related devices is also discussed. In the end, a technical roadmap for fabricating state-of-the-art blue PeLEDs is proposed.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
Yin Zhu, Li Xu, Boyang Li, Yifu Wang, Dongyu Li, Jing Ren, Haili Jiang, Lu Liu, Fuqiang Jiang, Jianzhong Zhang
Summary: This letter presents a color tuning strategy based on Tm3+ upconversion luminescence, achieving blue dominant and red dominant emissions through different excitation methods. The proposed strategy is particularly useful for in vivo applications, playing important roles in biological imaging and drug release.
Article
Nanoscience & Nanotechnology
Toshiki Sakata, Daisuke Kajiya, Ken-ichi Saitow
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Physical
Shiho Terada, Yunzi Xin, Ken-ichi Saitow
CHEMISTRY OF MATERIALS
(2020)
Article
Chemistry, Physical
Yufeng Wang, Ken-ichi Saitow
CHEMISTRY OF MATERIALS
(2020)
Article
Chemistry, Physical
Kaito Hanatani, Kumi Yoshihara, Masanori Sakamoto, Ken-ichi Saitow
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2020)
Article
Nanoscience & Nanotechnology
Masanori Sakamoto, Shiho Terada, Tomoya Mizutani, Ken-ichi Saitow
Summary: The field enhancement of Porous Si (PSi) was investigated through the enhancement of fluorescence intensity of a dye molecule. Nanocoral structure was observed on the surface of PSi after chemical processes and pulsed laser melting, showing large field enhancement with an enhancement factor (EF) of up to 545. The high field enhancement of Nanocoral Si was attributed to thermodynamic calculations and agreement between experimental and calculation results based on Mie scattering theory.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Taisei Ono, Yuping Xu, Toshiki Sakata, Ken-ichi Saitow
Summary: The study characterized and compared colloidal silicon quantum dots synthesized by different methods, revealing significant differences in their photoluminescence quantum yields, primarily influenced by surface coverage and ligand type. Furthermore, analysis of the core stress on the SiQDs provided important insights into their optoelectronic performance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Masakazu Takamatsu, Toshiki Sakata, Daisuke Kajiya, Ken-ichi Saitow
Summary: This article presents a simple and effective method for obtaining oriented films of pi-conjugated polymers. The method utilizes a cellulose template and thermal annealing to achieve high orientation of the films, resulting in stable folding performance and polarized fluorescence.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Shiho Terada, Honoka Ueda, Taisei Ono, Ken-ichi Saitow
Summary: This study developed a method for fabricating environmentally friendly quantum dots using rice husks, a byproduct of rice milling. The extracted SiO2 and Si powders from rice husks showed high yields and were used to synthesize decyl-passivated SiQDs with excellent photoluminescence properties. The colloidal solution of these SiQDs was further used to develop a SiQD LED with orange-red electroluminescence.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Analytical
Masanori Sakamoto, Ken-ichi Saitow
Summary: Silicon is considered a promising enhancement material due to its abundance, low toxicity, and high refractive index. A cost-effective and efficient fabrication method for a field enhancement substrate consisting of a two-dimensional Si wire array (2D-SiWA) was reported, demonstrating high sensor sensitivity and reproducibility. The large-area Si fluorescence sensor fabrication proved to be 50x less expensive, 20x faster, and 60,000x larger than the typical electron beam lithography method.
ANALYTICAL CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Yuping Xu, Shiho Terada, Yunzi Xin, Honoka Ueda, Ken-ichi Saitow
Summary: Colloidal silicon quantum dots (SiQDs) were synthesized with different ligand coverages and assembled into LEDs. The study found that ligand coverage significantly affected the performance of SiQD LEDs, especially in terms of electroluminescence turn-on voltage and external quantum efficiencies.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Keisuke Fujimoto, Toma Hayakawa, Yuping Xu, Nana Jingu, Ken-ichi Saitow
Summary: This study focuses on heavy-metal-free fluorophores, specifically silicon quantum dots (SiQDs), for next-generation light sources. The researchers synthesized SiQDs with red/green/blue photoluminescence (PL) using three different methods and evaluated their durability in flexible polymer films. They found that the nature of the terminating ligand on the SiQD surface significantly affected the PL stability. The insights gained from this study are important for designing light sources without heavy metals and integrating them into flexible and stretchable optoelectronic devices.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Inorganic & Nuclear
Sakiko Hirata, Ryoji Kusaka, Shogo Meiji, Seita Tamekuni, Kosuke Okudera, Shoken Hamada, Chihiro Sakamoto, Takumi Honda, Kosuke Matsushita, Satoru Muramatsu, Takayuki Ebata, Daisuke Kajiya, Ken-ichi Saitow, Toshiaki Ikeda, Takehiro Hirao, Takeharu Haino, Masayuki Watanabe, Yoshiya Inokuchi
Summary: A new technique called surface-enhanced infrared absorption (SEIRA) spectroscopy was used for structural investigation of lanthanide and actinide complexes with organic ligands. Thiol derivatives of ligands similar to diglycolamide (DGA), Cyanex-272, and TPEN were synthesized and attached to a gold surface on an Si prism. Aqueous solutions of lanthanide (Eu3+, Gd3+, and Tb3+) and actinide (Am3+) ions were loaded onto the surface to form ion complexes. The IR spectra obtained using SEIRA spectroscopy provided valuable information about the complexes and their extraction properties. SEIRA spectroscopy can be a useful tool for studying ion complexes and selective extraction.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yui Miura, Tsutomu Kashiwagi, Takeshi Fukuda, Akane Shichiri, Toshio Shiobara, Ken-ichi Saitow
Summary: In this study, a direct low-temperature synthesis method was demonstrated to produce alkoxysilanes with high yield and purity. The mechanochemical pre-treatment and silicide formation were found to significantly affect the yield of alkoxysilanes, and the stainless-steel milling medium acted as a mechanocatalyst.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Physical
Masanori Sakamoto, Ken-ichi Saitow
Summary: Silver nanostructures are important for developing efficient plasmonic materials due to their ability to produce localized surface plasmons and enhance electromagnetic fields. In this study, an optical technique was used to map the plasmons in silver nanohole array and nano-sawtooth structures. The results showed high enhancement factors up to 200 for the nano-sawtooth structure. The fabrication process for the silver nanostructures was straightforward and cost-effective.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Tomoya Mizutani, Haruhisa Ohta, Taiki Ueda, Tsutomu Kashiwagi, Takeshi Fukuda, Toshio Shiobara, Ken-ichi Saitow
Summary: Efficient low-temperature H-2 production was achieved by mechanochemically treating Si particles, and the Si-water reaction mechanism was understood. The use of discarded solar cells for reactant production is possible, but challenges related to Si particle preparation, hazardous chemicals, and unknown reaction mechanisms must be addressed.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)