Fine-grained phosphors for red-emitting mini-LEDs with high efficiency and super-luminance

Autor: Yu Kang, Shuxing Li, Rundong Tian, Guangzhu Liu, Haorui Dong, Tianliang Zhou, Rong-Jun Xie
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Advanced Ceramics, Vol 11, Iss 9, Pp 1383-1390 (2022)
Druh dokumentu: article
ISSN: 2226-4108
2227-8508
DOI: 10.1007/s40145-022-0617-z
Popis: Abstract Mini-LED backlights, combining color conversion materials with blue mini-LED chips, promise traditional liquid crystal displays (LCDs) with higher luminance, better contrast, and a wider color gamut. However, as color conversion materials, quantum dots (QDs) are toxic and unstable, whereas commercially available inorganic phosphors are too big in size to combine with small mini-LED chips and also have strong size-dependence of quantum efficiency (QE) and reliability. In this work, we prepare fine-grained Sr2Si5N8:Eu2+-based red phosphors with high efficiency and stability by treating commercially available phosphors with ball milling, centrifuging, and acid washing. The particle size of phosphors can be easily controlled by milling speed, and the phosphors with a size varying from 3.5 to 0.7 μm are thus obtained. The samples remain the same QE as the original ones (∼80%) even when their particle size is reduced to 3.2–3.5 μm, because they contain fewer surface suspension bond defects. More importantly, SrBaSi5N8:Eu2+ phosphors show a size-independent thermal quenching behavior and a zero thermal degradation. We demonstrate that red-emitting mini-LEDs can be fabricated by combining the SrBaSi5N8:Eu2+ red phosphor (3.5 μm in size) with blue mini-LED chips, which show a high external quantum efficiency (EQE) of above 31% and a super-high luminance of 34.3 Mnits. It indicates that fine and high efficiency phosphors can be obtained by the proposed method in this work, and they have great potentials for use in mini-LED displays.
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