Crystal structure of blue–white–yellow color-tunable Ca4Si2O7F2:Eu2+,Mn2+ phosphor and investigation of color tunability through energy transfer for single-phase white-light near-ultraviolet LEDs

Chien-Hao Huang; Ting-Shan Chan; Wei-Ren Liu; De-Yin Wang; Yi-Chen Chiu; Yao-Tsung Yeh; Teng-Ming Chen

doi:10.1039/C2JM33160H

Crystal structure of blue–white–yellow color-tunable Ca₄Si₂O₇F₂:Eu²⁺,Mn²⁺ phosphor and investigation of color tunability through energy transfer for single-phase white-light near-ultraviolet LEDs†

Chien-Hao Huang,*^ad Ting-Shan Chan,^b Wei-Ren Liu,^c De-Yin Wang,^d Yi-Chen Chiu,^a Yao-Tsung Yeh^a and Teng-Ming Chen*^d

Author affiliations

* Corresponding authors

^a Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan 30011, R.O.C
E-mail: Chien-Hao@itri.org.tw
Tel: +86-886-3-5732438

^b National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, Taiwan 30076, R.O.C

^c Department of Chemical Engineering, Chung Yuan Christian University, Chungli, Taiwan 32023, R.O.C

^d Phosphors Research Laboratory and Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan 30010, R.O.C
E-mail: tmchen@mail.nctu.edu.tw
Tel: +86-886-35731695

Abstract

The crystal structure of Ca₄Si₂O₇F₂:Eu²⁺,Mn²⁺ was refined and determined from X-ray diffraction (XRD) profiles obtained using a synchrotron light source by the Rietveld refinement method. It was found to crystallize into a monoclinic structure with the P2₁/c(14) space group. On examining the Mn²⁺-concentration-dependent photoluminescence properties, we found that the emission colors could be tuned from blue (0.152, 0.112) to white-light (0.351, 0.332) and eventually to yellow (0.430, 0.423) through energy transfer by changing the Eu²⁺/Mn²⁺ ratio. Moreover, energy transfer from a sensitizer Eu²⁺ to an activator Mn²⁺ occurs via a resonance-type dipole–quadrupole interaction mechanism, and the critical distances of the energy transfer were calculated to be 11.66 Å and 12.61 Å using concentration quenching and spectral overlap methods, respectively. Combining a 400 nm near-ultraviolet (NUV) chip and a single-phase white-emitting (Ca_0.96Eu_0.01Mn_0.03)₄Si₂O₇F₂ phosphor produced a white-light NUV LED with CIE chromaticity coordinates of (0.347, 0.338) and a warm color temperature of 4880 K.

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Article information

DOI: https://doi.org/10.1039/C2JM33160H
Article type: Paper
Submitted: 18 May 2012
Accepted: 25 Jul 2012
First published: 26 Jul 2012

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J. Mater. Chem., 2012,22, 20210-20216

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Crystal structure of blue–white–yellow color-tunable Ca₄Si₂O₇F₂:Eu²⁺,Mn²⁺ phosphor and investigation of color tunability through energy transfer for single-phase white-light near-ultraviolet LEDs

C. Huang, T. Chan, W. Liu, D. Wang, Y. Chiu, Y. Yeh and T. Chen, J. Mater. Chem., 2012, 22, 20210 DOI: 10.1039/C2JM33160H

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