A high efficiency broad-band near-infrared Ca 2LuZr 2Al 3O 12:Cr 3+ garnet phosphor for blue LED chips

Author(s): Liangliang Zhang ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Sheng Zhang ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Zhendong Hao ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Xia Zhang ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Guo-hui Pan ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Yongshi Luo ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Huajun Wu ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵ , Jiahua Zhang ¹ ^, ² ^, ³ ^, ⁴ ^, ⁵

Publication date (Electronic): 2018

Journal: Journal of Materials Chemistry C

Publisher: Royal Society of Chemistry (RSC)

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Abstract

The garnet Ca ₂LuZr ₂Al ₃O ₁₂ (CLZA) is a promising broad-band NIR phosphor for blue LED chips when it is doped with Cr ³⁺.

Abstract

The garnet Ca ₂LuZr ₂Al ₃O ₁₂ (CLZA) is a promising broad-band NIR phosphor for blue LED chips when it is doped with Cr ³⁺. The photoelectric efficiency of the pc-LED fabricated from CLZA:Cr ³⁺ and a 460 nm LED chip, in the 750–820 nm spectral range, was 4.1%, which was superior to the efficiency of a tungsten lamp (2.9%). In CLZA’s structure, Cr ³⁺ occupied Ca ²⁺/Lu ³⁺ and Zr ⁴⁺ sites and showed two luminescence centers. The crystal strength parameters of Ce ³⁺ and Cr ³⁺ were calculated to show the coordination environment of the dodecahedral and octahedral sites in CLZA. Low absorbance of Cr ³⁺ was the main constraint on quantum efficiency. Ce ³⁺ was thus introduced as a sensitizer to improve the absorbance. An efficient energy transfer process can be observed between Ce ³⁺ and Cr ³⁺ in CLZA. The temperature dependent properties of CLZA:Cr ³⁺ were also studied. Two thermal processes (thermal quenching and thermal ionization) were observed and discussed in detail.

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Most cited references 39

Record: found
Abstract: found
Article: not found

A brief review on the history of human functional near-infrared spectroscopy (fNIRS) development and fields of application.

Marco Ferrari, Valentina Quaresima (2012)

This review is aimed at celebrating the upcoming 20th anniversary of the birth of human functional near-infrared spectroscopy (fNIRS). After the discovery in 1992 that the functional activation of the human cerebral cortex (due to oxygenation and hemodynamic changes) can be explored by NIRS, human functional brain mapping research has gained a new dimension. fNIRS or optical topography, or near-infrared imaging or diffuse optical imaging is used mainly to detect simultaneous changes in optical properties of the human cortex from multiple measurement sites and displays the results in the form of a map or image over a specific area. In order to place current fNIRS research in its proper context, this paper presents a brief historical overview of the events that have shaped the present status of fNIRS. In particular, technological progresses of fNIRS are highlighted (i.e., from single-site to multi-site functional cortical measurements (images)), introduction of the commercial multi-channel systems, recent commercial wireless instrumentation and more advanced prototypes. Copyright © 2012 Elsevier Inc. All rights reserved.

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Record: found
Abstract: not found
Article: not found

Nondestructive measurement of fruit and vegetable quality by means of NIR spectroscopy: A review

Bart M Nicolai, Katrien Beullens, Els Bobelyn … (2007)

0 comments Cited 238 times – based on 0 reviews      Review now

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Record: found
Abstract: found
Article: found

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Ultrasensitive broadband phototransistors based on perovskite/organic-semiconductor vertical heterojunctions

Chao Xie, Peng You, Zhike Liu … (2017)

Organolead halide perovskites have emerged as the most promising materials for various optoelectronic devices, especially solar cells, because of their excellent optoelectronic properties. Here, we present the first report of low-voltage high-gain phototransistors based on perovskite/organic-semiconductor vertical heterojunctions, which show ultrahigh responsivities of ~109A W–1 and specific detectivities of ~1014 Jones in a broadband region from the ultraviolet to the near infrared. The high sensitivity of the devices is attributed to a pronounced photogating effect that is mainly due to the long carrier lifetimes and strong light absorption in the perovskite material. In addition, flexible perovskite photodetectors have been successfully prepared via a solution process and show high sensitivity as well as excellent flexibility and bending durability. The high performance and facile solution-based fabrication of the perovskite/organic-semiconductor phototransistors indicate their promise for potential application for ultrasensitive broadband photodetection.