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4 results on '"Penghao Tang"'

1. Transfer-free rapid growth of 2-inch wafer-scale patterned graphene as transparent conductive electrodes and heat spreaders for GaN LEDs

Author

Fangzhu Xiong, Jie Sun, Penghao Tang, Weiling Guo, Yibo Dong, Zaifa Du, Shiwei Feng, and Xuan Li

Subjects
Materials of engineering and construction. Mechanics of materials, TA401-492, Chemistry, QD1-999
Abstract

Abstract A technique for the transfer-free growth of 2-inch wafer-scale patterned graphene directly on GaN LED epilayers is introduced. High-quality graphene as transparent electrodes and heat spreaders is synthesized directly on GaN by PECVD at only 600 °C deposition temperature and within 3 min growth time. Co acts as both the catalyst for graphene growth and the dry etching mask for GaN mesas, which greatly improves the efficiency of the semiconductor device process. Elegantly, the graphene growth is in accordance with the shape of Co, which offers a lithography-free patterning technique of the graphene. Afterward, using our penetration etching method through the PMMA and graphene layers, the Co is peacefully removed, and in-situ Ohmic contact is achieved between the graphene and p-GaN where the contact resistivity is only 0.421 Ω cm2. The graphene sheet resistance is as low as 631.2 Ω sq−1. The device is also superior to the counterpart graphene-free LED in terms of heat spreading behavior, as evidenced by the lower junction temperature and thermal resistance. Most importantly, the developed technique produces graphene with excellent performance and is intrinsically more scalable, controllable, and semiconductor industry compatible than traditionally transferred graphene.

Published
2023
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2. Advancements in Micro-LED Performance through Nanomaterials and Nanostructures: A Review

Author

Aoqi Fang, Zaifa Du, Weiling Guo, Jixin Liu, Hao Xu, Penghao Tang, and Jie Sun

Subjects
micro-LED, quantum dot, nanomaterials, nanostructures, Chemistry, QD1-999
Abstract

Micro-light-emitting diodes (μLEDs), with their advantages of high response speed, long lifespan, high brightness, and reliability, are widely regarded as the core of next-generation display technology. However, due to issues such as high manufacturing costs and low external quantum efficiency (EQE), μLEDs have not yet been truly commercialized. Additionally, the color conversion efficiency (CCE) of quantum dot (QD)-μLEDs is also a major obstacle to its practical application in the display industry. In this review, we systematically summarize the recent applications of nanomaterials and nanostructures in μLEDs and discuss the practical effects of these methods on enhancing the luminous efficiency of μLEDs and the color conversion efficiency of QD-μLEDs. Finally, the challenges and future prospects for the commercialization of μLEDs are proposed.

Published
2024
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3. Multifunctional ZnO-porous carbon composites derived from MOF-74(Zn) with ultrafast pollutant adsorption capacity and supercapacitance properties

Author

Lingjie Wang, Aobo Geng, Chi Song, Jie Liu, Lijie Xu, Penghao Tang, Qiang Zhong, and Lu Gan

Subjects
Supercapacitor, Aqueous solution, Materials science, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Adsorption, chemistry, Desorption, Rhodamine B, Metal-organic framework, Composite material, 0210 nano-technology, Pyrolysis, Carbon
Abstract

In the present study, the ZnO-porous carbon (ZnO-C) composites were prepared by pyrolyzing MOF-74 (Zn) precursor at different pyrolysis temperatures. The ZnO-C composites were endowed with ultrafast organic dye adsorption capability and promising supercapacitance properties due to the existence of abundant pores within the composite structures. Having a surface area of 782.971 m2/g and pore volume of 0.698 m3/g, the composite pyrolyzed at 1000 °C (ZnO-C1000) exhibited the best performance for organic pollutant uptake. Specifically, 50 mg of ZnO-C1000 could remove all the Rhodamine B dye from 100 mL aqueous solution within 0.5 h even the dye concentration was as high as 40 mg/L. It was also shown that the ZnO-C composites could preserve their adsorption capability in a wide pH range, and keep promising dye adsorption stability after consecutive adsorption/desorption cycles. Furthermore, the ZnO-C900 exhibited a specific capacitance of 197.84 F/g as the supercapacitance electrode with good stability (∼97.8% capacitance retention after 1000 cycles). The overall results indicate that the prepared ZnO-C composites have multi-application potentials which can be utilized as efficient pollutant absorbents as well as electrode materials for supercapacitors.

Published
2019

4. POM derived UOR and HER bifunctional NiS/MoS2 composite for overall water splitting

Author

Yang Zheng, Xinxin Xu, Xiaoguang Sang, and Penghao Tang

Subjects
Materials science, Electrolytic cell, 02 engineering and technology, Electrolyte, 010402 general chemistry, Electrocatalyst, 01 natural sciences, law.invention, Inorganic Chemistry, chemistry.chemical_compound, law, Materials Chemistry, Physical and Theoretical Chemistry, Bifunctional, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Cathode, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Anode, chemistry, Chemical engineering, Electrode, Ceramics and Composites, Water splitting, 0210 nano-technology
Abstract

A binder free electrode is fabricated by “planting” Anderson type polyoxometalate derived NiS/MoS2 “follower” on functional carbon paper. This electrode shows excellent UOR activity. In 1 ​M KOH containing 0.4 ​M urea, it only needs 1.42 and 1.43 ​V voltage to achieve 50 and 100 ​mA ​cm−2 current. On the contrary, to reach 50 and 100 ​mA ​cm−2, OER require 1.68 and 1.75 ​V. Besides promising UOR activity, the HER property of this electrode is also attractive. In urea containing electrolyte, its η10 and η100 are only 128 and 283 ​mV. More importantly, it shows excellent stability in both UOR and HER. In electrolytic cell, with this electrode as cathode and anode simultaneously, only 1.42 and 1.49 ​V voltage is needed to obtain 10 and 50 ​mA ​cm−2 current in urea containing electrolyte. Without urea, the voltages increase to 1.69 and 1.75 ​V. The excellent UOR and HER properties suggest this binder free electrode is competent for low energy consumption H2 production.

Published
2020
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