Control of High Color Rendition Phosphors and

Their Application in White Light-emitting DiodesMu-Huai Fang and Ru-Shi Liu*

Department of Chemistry, National Taiwan University, Taipei 106, Taiwan Abstract

The first part focuses on narrow red emission band fluoride phosphors Rb2SiF6:Mn4+ and KNaSiF6:Mn4+ for warm white light-emitting diodes. The photoluminescence properties are

found to be highly related to the pressure especially for the zero-phonon line (ZPL), which is strongly correlated to the local coordination environment. The distortion of the MnF62-

octahedron will then enhance the intensity of the ZPL.

Photoluminescence properties

Structure

In the second part, a series of SrLiAl3N4:Eu2+ red phosphors are synthesized at a different pressure from 1 atm to 1,000 atm. the photoluminescence intensity, particle size, and

quantum efficiency increase with increasing applied pressure. a series of Sr(Li1-xSix)(Al1-xMgx)3N4:Eu2+ phosphors solid-solution are successfully synthesized. It also leads to the

unexpected red-shift in PL spectra from 650-679 nm, which is out of range of SLA (650 nm) and SMS (610 nm).

In the third part, Sr4.7−xBaxEu0.3(PO4)3Cl (0 ≤ x ≤ 2.5) materials were synthesized. Real full-spectrum lighting can be achieved by Sr3.4Ba1.3Eu0.3(PO4)3Cl. The LED package device not

only possesses high Ra and R9 values ( > 95) but also compensates for the 480 – 520 nm cyan gap, which widens the research on full-spectrum lighting.

Photoluminescence properties

Structure

14 15 16 17 18

amb. (after)

29.9 GPa

27.8 GPa

26.0 GPa

24.0 GPa

21.5 GPa

18.9 GPa

16.5 GPa

14.5 GPa

12.2 GPa

10.4 GPa

8.0 GPa

6.3 GPa

4.1 GPa

1.9 GPa

amb.

Inte

nsit

y (a

.u.)

Wavenumber (103 cm

-1)

ZPL2E

g to

4A

2g

20 25 30 35

30.4 GPa

27.2 GPa

24.5 GPa

20 GPa

15.8 GPa

12 GPa

8.4 GPa

4.5 GPa

ambient

Inte

nsity

(a.u

.)

Wavenumber (103 cm

-1)

4A

2→

4A

2→

amb. after

0 5 10 15 20 25 300.86

0.88

0.90

0.92

0.94

0.96

0.98

1.00

1.02

IZPL

/ I6

Inte

nsi

ty (

a.u

.)

Pressure (GPa)0 5 10 15 20 25 3015.0

15.2

15.4

15.6

15.8

16.0

16.2

22

24

26

28

30

32

emission

4A

2g

4T

2g

2E

g

4A

2g

4A

2g

4T

1g

Wa

ven

um

ber

(10

3 c

m-1

)

Pressure (GPa)

ZPL

excitation

LED package

Structure

Photoluminescence properties

350 400 450 500 550 600

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

100 MPa

50 MPa

0.9 MPa

0.7 MPa

0.5 MPa

0.3 MPa

0.1 MPa

600 650 700 750

100 MPa

50 MPa

0.9 MPa

0.7 MPa

0.5 MPa

0.3 MPa

0.1 MPa

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

100500.9 0.7 0.5 0.3 0.1

IQE

Absorption

EQE

Pressure (MPa)

Quantum Efficiency

Sample Ex. (nm) Em. (nm) FWHMRelative Int.

(%)

RQ O .

(%, relative)

100 Mpa 460 654 62 100 100

50 Mpa 460 654 65 91 96

0.9 Mpa 460 650 58 59 56

0.7 Mpa 460 651 57 55 52

0.5 Mpa 460 651 56 52 49

0.3 Mpa 460 652 58 53 50

0.1 Mpa 460 653 57 47 45

Morphology

ICP-AES / XANES

ion

Pressure

(MPa)

Sr (mol%) Li (mol%) Al (mol%) Sr：Li：Al

0.1 19.5(4) 14.7(5) 65.8(4) 1：0.75(3)：3.36(3)

0.3 19.6(0) 18.2(9) 61.9(4) 1：0.92(5)：3.12(2)

0.5 19.4(4) 17.3(5) 63.3(2) 1：0.89(3)：3.27(1)

0.7 19.5(8) 17.0(5) 63.5(1) 1：0.87(3)：3.26(1)

0.9 19.1(4) 17.0(0) 63.8(1) 1：0.89(0)：3.33(1)

50 19.1(5) 19.6(6) 61.2(1) 1：1.02(3)：3.19(1)

100 19.1(5) 19.6(0) 61.3(2) 1：1.03(0)：3.22(1)

Theoretical

value20 20 60 1：1：3 6970 6975 6980

Energy (eV)

No

rma

lize

d i

nte

nsi

ty

0.1 MPa

0.3 MPa

0.5 MPa

0.7 MPa

0.9 MPa

50 MPa

100 MPa

Eu2+

Eu3+

Device

Structure Photoluminescence

550 600 650 700 750 800

SLA

0.1 Mg/Si

0.2 Mg/Si

0.3 Mg/Si

0.4 Mg/Si

0.5 Mg/Si

0.6 Mg/Si

0.7 Mg/Si

0.8 Mg/Si

0.9 Mg/Si

SMS

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

350 400 450 500 550 600

SLA

0.1 Mg/Si

0.2 Mg/Si

0.3 Mg/Si

0.4 Mg/Si

0.5 Mg/Si

0.6 Mg/Si

0.7 Mg/Si

0.8 Mg/Si

0.9 Mg/Si

SMS

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

Morphology Morphology

XANES

6960 6965 6970 6975 6980 6985 6990 6995 70000.0

0.2

0.4

0.6

0.8

1.0 SLA

0.1 Mg/Si

0.2 Mg/Si

0.3 Mg/Si

0.4 Mg/Si

0.5 Mg/Si

0.6 Mg/Si

0.7 Mg/Si

0.8 Mg/Si

0.9 Mg/Si

SMS

Eu2+

Eu3+

No

rma

lize

d i

nte

nsi

ty

Energy (eV)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00.0

0.2

0.4

0.6

0.8

1.0

(SLA) (SMS)

Rel

ati

ve

Eu

2+ c

on

cen

trati

on

x value

Structurex = 0

x = 0.5

x = 1

x = 1.3

x = 1.5

x = 2

2 (degree)

In

ten

sit

y (

a.u

.)

x = 2.25

x = 2.5

PDF#83-0974, Sr5(PO4)3Cl

20 30 40 50 60 70

PDF#70-2318, Ba5(PO4)3Cl

0.5 1.0 1.5 2.0 2.5

0.0

0.2

0.4

0.6

0.8

1.0

Occ

up

ati

on

x

Ba at Sr(I)

Ba at Sr(II)

Photoluminescence

450 500 550 600

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

x = 0

x = 0.5

x = 1

x = 1.3

x = 1.5

x = 2

x = 2.5

33000 30000 27000 24000 21000 18000

x = 1.5

x = 1

x = 0.5

Inte

nsi

ty (

a.u

.)

Wavenumber (cm-1

)

Sr4.7-x

BaxEu

0.3(PO

4)

3Cl

x = 0

350 400 450 500 550 600

Wavelength (nm)

0.0 0.5 1.0 1.50.1

0.2

0.3

0.4

0.5

0.6

0.7

Sr4.7-x

BaxEu

0.3(PO

4)3Cl

obs

= 480 - 520 nm

Lif

eti

me (

s)

Ba concentration (x)

obs

= 440 - 460 nm

33000 30000 27000 24000 21000 18000

temp. 10 K

Sr3.2

Ba1.5

Eu0.3

(PO4)3Cl

440

437

435

432

430

Inte

nsi

ty (

a.u

.)

Wavenumber (cm-1

)

obs = 500 nm

temp. 77 K

420

exc

(nm)

obs = 450 nm

300 350 400 450 500 550 600

Wavelength (nm)

0.0 0.5 1.0 1.5 2.0 2.510

0

101

102

103

104

obs

= 440 - 460 nm

x = 1.5

x = 1.5

x = 0

x = 0.5

Sr4.7-x

BaxEu

0.3(PO

4)

3Cl

Inte

nsi

ty (

a.u

.)

Time (s)

x = 1

x = 0.5

x = 1

obs

= 480 - 520 nm

Eu Oxidation

Device

400 600

BAM

Sr4.7

Eu0.3

(PO4)3Cl

400 450 500 550 600 650 700

Wavelength (nm)

Sr3.4

Ba1.3

Eu0.3(PO

4)

3Cl

Mechanism

Publication:

Paper(1) Fang, M. H.; Wu, W. L.; Jin, Y.; Lesniewski, T.; Mahlik, S.; Grinberg, M.; Brik, M. G.; Srivastava, A. M.; Chiang, C. Y.;

Zhou, W.; Jeong, D.; Kim, S. H.; Leniec, G.; Kaczmarek, S. M.; Sheu, H. S.; Liu, R. S. Control of Luminescence via Tuning of

Crystal Symmetry and Local Structure in Mn4+－Activated Narrow Band Fluoride Phosphors. Angew. Chem. Int. Ed. 2018, 57,

1797 –1801.

(2) Leaño, J. L.; Fang, M. H.; Liu, R. S. Critical Review-Narrow-Band Emission of Nitride Phosphors for Light-Emitting

Diodes: Perspectives and Opportunities. ECS J. Solid State Sci. Technol. 2018, 7, R3111－R3133.

(3) Zhang, X.; Fang, M. H.; Tsai, Y.-T.; Lazarowska, A.; Mahlik, S.; Lesniewski, T.; Grinberg, M.; Pang, W. K.; Pan, F.; Liang,

C.; Liu, R. S. Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach

Narrow-Band-Emission for Light-Emitting Diodes Application. Chem. Mater. 2017, 29, 6781－6792.

(4) Zhang, N.; Tsai, Y. T.; Fang, M. H.; Ma, C. G.; Lazarowska, A.; Mahlik, S.; Grinberg, M.; Chiang, C. Y.; Zhou, W.; Lin, J.

G.; Liu, R. S. Aluminate Red Phosphor in Light-Emitting Diodes: Theoretical Calculations, Charge Varieties, and High-

Pressure Luminescence Analysis. ACS Appl. Mater. Interfaces 2017, 9, 23995－24004.

(5) Wu, W. L.; Fang, M. H.; Zhou, W.; Lesniewski, T.; Mahlik, S.; Grinberg, M.; Brik, M. G.; Sheu, H. S.; Cheng, B. M.; Wang,

J.; Liu, R. S. High Color Rendering Index of Rb2GeF6:Mn4+ for Light-Emitting Diodes. Chem. Mater. 2017, 29, 935－939.

(6) Lin, C. C.; Tsai, Y. T.; Johnston, H. E.; Fang, M. H.; Yu, F.; Zhou, W.; Whitfield, P.; Li, Y.; Wang, J.; Liu, R. S. Enhanced

Photoluminescence Emission and Thermal Stability from Introduced Cation Disorder in Phosphors. J. Am. Chem. Soc. 2017,

139, 11766－11770.

(7) Huang, Y. K.; Jena, A.; Chen, Y. T.; Fang, M. H.; Yang, N. H.; Chang, H.; Liu, R. S. Nanosized-Fe3PtN Supported on

Nitrogen-Doped Carbon as Electro-Catalyst for Oxygen Reduction Reaction. Int. J. Hydrogen Energy 2017, 42, 15761－15769.

(8) Jin, Y.; Fang, M. H.; Grinberg, M.; Mahlik, S.; Lesniewski, T.; Brik, M.; Luo, G.-Y.; Lin, J. G.; Liu, R. S. Narrow Red

Emission Band Fluoride Phosphor KNaSiF6:Mn4+ for Warm White Light-Emitting Diodes. ACS Appl. Mater. Interfaces 2016, 8,

11194－11203.

(9) Fang, M. H.; Ni, C.; Zhang, X.; Tsai, Y. T.; Mahlik, S.; Lazarowska, A.; Grinberg, M.; Sheu, H. S.; Lee, J. F.; Cheng, B. M.;

Liu, R. S. Enhance Color Rendering Index via Full Spectrum Employing the Important Key of Cyan Phosphor. ACS Appl.

Mater. Interfaces 2016, 8, 30677－30682.

(10) Wei, L. L.; Lin, C. C.; Wang, Y.-Y.; Fang, M. H.; Jiao, H.; Liu, R. S. Photoluminescent Evolution Induced By Structural

Transformation through Thermal Treating in the Red Narrow-Band Phosphor K2GeF6:Mn4+. ACS Appl. Mater. Interfaces 2015,

7, 10656－10659.

(11) Wei, L. L.; Lin, C. C.; Fang, M. H.; Brik, M. G.; Hu, S. F.; Jiao, H.; Liu, R. S. A Low-Temperature Co-Precipitation

Approach to Synthesize Fluoride Phosphors K2MF6:Mn4+ (M= Ge, Si) for White LED Applications. J. Mater. Chem. C 2015, 3,

1655－1660.

(12) Fang, M. H.; Nguyen, H. D.; Lin, C. C.; Liu, R. S. Preparation of a Novel Red Rb2SiF6:Mn4+ Phosphor with High

Thermal Stability through a Simple One-Step Approach. J. Mater. Chem. C 2015, 3, 7277－7280.

(13) Nguyen, H. D.; Lin, C. C.; Fang, M. H.; Liu, R. S. Synthesis of Na2SiF6:Mn4+ Red Phosphors for White LED Applications

by Co-precipitation. J. Mater. Chem. C 2014, 2, 10268－10272.

Patent1. “螢光粉的製備方法” 段南岩、方牧懷、林群哲、劉如熹、蔡松祐 (台灣專利-已通過)

2. “一種具高演色性與高熱特性之紅色氮化物螢光粉” 林英志、王立群、吳信謀、洪浩恩、謝繼興、劉如熹、蔡宜

廷、林群哲、方牧懷(台灣專利-已通過)

3. “發光二極體裝置” 段南岩、方牧懷、林群哲、劉如熹、蔡松祐 (台灣專利-已通過)

4. “螢光粉的製備方法” 段南岩、方牧懷、林群哲、劉如熹、蔡松祐 (台灣專利-審查中)

5. “一種具高演色性與高熱特性之紅色氮化物螢光粉” 林英志、王立群、吳信謀、洪浩恩、謝繼興、劉如熹、蔡宜

廷、林群哲、方牧懷 (台灣專利-審查中)

6. “發光二極體之波長轉換結構” 方牧懷、王筱姍、劉如熹 (台灣專利-審查中)

Topic 1 – Mn4+-doped narrowband fluoride phosphor

Topic 2 – Eu2+-doped narrowband nitride phosphor

Topic 3 – Eu2+-dopedbroadband cyan phosphor