CaF<sub>2</sub>纳米晶粒结构相变行为的尺寸依赖性

巩蕾; 王婧姝; 张俊凯; 陈广博; 张晗; 武晓鑫; 胡廷静; 崔航

doi:10.11858/gywlxb.20210842

Size-Dependent Structural Phase Transition Behaviors of CaF₂ Nanocrystals

doi: 10.11858/gywlxb.20210842

1.
Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, Jilin Normal University, Siping 136000, Jilin, China
2.
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, Jilin, China

Funds: National Natural Science Foundation of China (11904128); Thirteenth Five-Year Program for Science and Technology of Education Department of Jilin Province (JJKH20200410KJ); Academic Graduate Students Scientific Research Innovation Fund of Jilin Normal University (202005)

More Information

Author Bio:
GONG Lei (1998－), female, bachelor, major in high pressure structural phase transition of nanomaterials. E-mail: gl15734441063@126.com

Corresponding author: WANG Jingshu (1982－), female, doctor, associate professor, major in high pressure behavior of nanomaterials. E-mail: wjs@jlnu.edu.cn

摘要

摘要: 利用原位高压同步辐射X射线衍射方法，对尺寸为11 nm的CaF₂纳米晶粒进行高压结构相变和压缩特性研究。当压力为12 GPa时，观察到由萤石结构向 α-PbCl₂结构转变的一次相变，该相变压力点远高于体材料，但略低于粒径更小的 CaF2 纳米晶体。相比体材料，纳米尺寸的CaF₂样品的体弹模量更大，说明其更难被压缩。当压力释放至常压时，11 nm的CaF₂纳米晶粒的α-PbCl₂型亚稳相结构被保留下来，相变不可逆。分析了影响11 nm CaF₂纳米晶粒独特高压行为的原因，判定尺寸效应为主要因素，该尺寸下较高的表面能导致结构稳定性增强和体积模量增加。
- 高压 /
- 氟化钙纳米晶粒 /
- 相变 /
- X射线衍射 /
- 尺寸效应
Abstract: CaF₂ nanocrystals with a size of 11 nm have been investigated using X-ray diffraction technique under high pressure. A phase transition from the fluorite structure to the α-PbCl₂-type structure has been observed at 12 GPa, which is much higher than the value observed in the bulk CaF₂ and slightly lower than the one in smaller-sized CaF₂ nanocrystals. The compressibility of the CaF₂ nanocrystals is discussed, an obviously higher incompressibility than the bulk CaF₂ is observed. The α-PbCl₂-type metastable phase is retained when the pressure is released to ambient conditions. The unique high-pressure behaviors of the 11 nm-sized CaF₂ nanocrystals are attributed to defects and grain size effect. The grain size effect is considered to be the main factor influencing the high-pressure behaviors of the CaF₂ nanocrystals. When the size of the CaF₂ nanocrystals is as small as 11 nm, the higher surface energy leads to the enhancement of the structural stability and the increase of the bulk modulus.
- high pressure /
- CaF₂ nanocrystals /
- phase transition /
- X-ray diffraction /
- size effect

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Figure 1. (a) TEM image of the as-synthesized CaF₂ nanocrystals; (b) particle size distribution of the CaF₂ nanocrystals

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Figure 2. Rietveld refinement of the diffraction pattern of the synthesized CaF₂ nanoparticles (Red dots, upper (blue), and lower (black) solid lines represent experimental, calculated, and residual patterns, respectively.)

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Figure 3. High-pressure XRD patterns of the CaF₂ nanocrystals, in which the peak (marked by asterisk) is derived from the gasket

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Figure 4. Rietveld refinement of the diffraction pattern of the CaF₂ nanocrystals at ambient conditions after decompression (Red dots, upper (blue), and lower (black) lines represent experimental, calculated, and residual patterns, respectively.)

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Figure 5. Unit-cell volume as a function of pressure determined for the 11 nm-sized CaF₂ nanocrystals (Solid curves are the Birch-Murnaghan EOS fits to the experimental data. Error bars are observed when they are large enough to exceed the sizes of the marked dots.)

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Figure 6. HRTEM image of the as-synthesized 11 nm-sized CaF₂ nanocrystals.

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Table 1. Transition pressure (${p}{_{\rm T}}$), and EOS parameters (B₀ and B₀ ′) of the fluorite-type and the α-PbCl₂-type CaF₂

Morphology	Size	$p{_{\rm T}} $/GPa	${B{_0 } } $/GPa		B₀ ′
Morphology	Size	$p{_{\rm T}} $/GPa	Fm3m	Pnma	Fm3m	Pnma
Bulk	Micro	9.5^[21]	87(5)^[21]	74(5)^[22]	5	4.7
		9^[34]	81(1)^[34]		5.22
		8.1^[20]	79.54^[20]	70.92^[20]	4.54	4.38
Nanocrystals	8 nm	14^[23]	112(6)	93(9)	5	4
	23 nm	9.5^[24]	103(2)^[24]	78(2)^[24]	5	4
	11 nm	12	109(5)	89(1)	5	4

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参考文献(34)

[1]	WANG G F, PENG Q, LI Y D. Upconversion luminescence of monodisperse CaF₂: Yb³⁺/Er³⁺ nanocrystals [J]. Journal of the American Chemical Society, 2009, 131(40): 14200–14201. doi: 10.1021/ja906732y
[2]	ZHANG C M, LI C X, PENG C, et al. Facile and controllable synthesis of monodisperse CaF₂ and CaF₂: Ce³⁺/Tb³⁺ hollow spheres as efficient luminescent materials and smart drug carriers [J]. Chemistry—A European Journal, 2010, 16(19): 5672–5680. doi: 10.1002/chem.200903137
[3]	ALHARBI N D. Size controlled CaF₂ nanocubes and their dosimetric properties using photoluminescence technique [J]. Journal of Nanomaterials, 2015: 136957.
[4]	XIAO G J, WANG K, ZHU L, et al. Pressure-induced reversible phase transformation in nanostructured Bi₂Te₃ with reduced transition pressure [J]. The Journal of Physical Chemistry C, 2015, 119(7): 3843–3848. doi: 10.1021/jp512565b
[5]	GUPTA S K, ZUNIGA J P, POKHREL M, et al. High pressure induced local ordering and tunable luminescence of La₂Hf₂O₇: Eu³⁺ nanoparticles [J]. New Journal of Chemistry, 2020, 44(14): 5463–5472. doi: 10.1039/D0NJ00585A
[6]	ZHAO R, WANG P, YAO B B, et al. Co-effect on zinc blende-rocksalt phase transition in CdS nanocrystals [J]. RSC Advances, 2015, 5(23): 17582–17587. doi: 10.1039/C4RA14798G
[7]	ZHANG J, ZHU H Y, WU X X, et al. Plasma-assisted synthesis and pressure-induced structural transition of single-crystalline SnSe nanosheets [J]. Nanoscale, 2015, 7(24): 10807–10816. doi: 10.1039/C5NR02131F
[8]	MENG L Y, LANE J M D, BACA L, et al. Shape dependence of pressure-induced phase transition in CdS semiconductor nanocrystals [J]. Journal of the American Chemical Society, 2020, 142(14): 6505–6510. doi: 10.1021/jacs.0c01906
[9]	SRIVASTAVA A, TYAGI N, SHARMA U S, et al. Pressure induced phase transformation and electronic properties of AlAs [J]. Materials Chemistry and Physics, 2011, 125(1/2): 66–71.
[10]	TOLBERT S H, ALIVISATOS A P. Size dependence of a first order solid-solid phase transition: the wurtzite to rock salt transformation in CdSe nanocrystals [J]. Science, 1994, 265(5170): 373–376. doi: 10.1126/science.265.5170.373
[11]	MARTÍN-RODRÍGUEZ R, GONZÁLEZ J, VALIENTE R, et al. Reversibility of the zinc-blende to rock-salt phase transition in cadmium sulfide nanocrystals [J]. Journal of Applied Physics, 2012, 111(6): 063516. doi: 10.1063/1.3697562
[12]	BUSHIRI M J, VINOD R, SEGURA A, et al. Pressure-induced phase transition in hydrothermally grown ZnO nanoflowers investigated by Raman and photoluminescence spectroscopy [J]. Journal of Physics: Condensed Matter, 2015, 27(38): 385401. doi: 10.1088/0953-8984/27/38/385401
[13]	WANG Z W, GUO Q X. Size-dependent structural stability and tuning mechanism: a case of zinc sulfide [J]. The Journal of Physical Chemistry C, 2009, 113(11): 4286–4295. doi: 10.1021/jp808244a
[14]	LV H, YAO M G, LI Q J, et al. Effect of grain size on pressure-induced structural transition in Mn₃O₄ [J]. The Journal of Physical Chemistry C, 2012, 116(3): 2165–2171. doi: 10.1021/jp2067028
[15]	WANG L, YANG W G, DING Y, et al. Size-dependent amorphization of nanoscale Y₂O₃ at high pressure [J]. Physical Review Letters, 2010, 105(9): 095701. doi: 10.1103/PhysRevLett.105.095701
[16]	SWAMY V, KUZNETSOV A, DUBROVINSKY L S, et al. Size-dependent pressure-induced amorphization in Nanoscale TiO₂ [J]. Physical Review Letters, 2006, 96(13): 135702. doi: 10.1103/PhysRevLett.96.135702
[17]	LI Q J, LIU B B, WANG L, et al. Pressure-induced amorphization and polyamorphism in one-dimensional single-crystal TiO₂ nanomaterials [J]. The Journal of Physical Chemistry Letters, 2010, 1(1): 309–314. doi: 10.1021/jz9001828
[18]	QUAN Z W, WANG Y X, BAE I T, et al. Reversal of hall-petch effect in structural stability of PbTe nanocrystals and associated variation of phase transformation [J]. Nano Letters, 2011, 11(12): 5531–5536. doi: 10.1021/nl203409s
[19]	WANG J S, CUI Q L, HU T J, et al. Pressure-induced amorphization in BaF₂ nanoparticles [J]. The Journal of Physical Chemistry C, 2016, 120(22): 12249–12253. doi: 10.1021/acs.jpcc.6b01858
[20]	CUI S X, FENG W X, HU H Q, et al. Structural stabilities, electronic and optical properties of CaF₂ under high pressure: a first-principles study [J]. Computational Materials Science, 2009, 47(1): 41–45. doi: 10.1016/j.commatsci.2009.06.011
[21]	GERWARD L, OLSEN J S, STEENSTRUP S, et al. X-ray diffraction investigations of CaF₂ at high pressure [J]. Journal of Applied Crystallography, 1992, 25(5): 578–581. doi: 10.1107/S0021889892004096
[22]	DORFMAN S M, JIANG F M, MAO Z, et al. Phase transitions and equations of state of alkaline earth fluorides CaF₂, SrF₂, and BaF₂ to Mbar pressures [J]. Physical Review B, 2010, 81(17): 174121. doi: 10.1103/PhysRevB.81.174121
[23]	WANG J S, HAO J, WANG Q S, et al. Pressure-induced structural transition in CaF₂ nanocrystals [J]. Physica Status Solidi B, 2011, 248(5): 1115–1118. doi: 10.1002/pssb.201000627
[24]	WANG J S, YANG J H, HU T J, et al. Structural phase transition and compressibility of CaF₂ nanocrystals under high pressure [J]. Crystals, 2018, 8(5): 199. doi: 10.3390/cryst8050199
[25]	WANG J S, ZHU H Y, MA C L, et al. High-pressure behaviors of SrF₂ nanocrystals with two morphologies [J]. The Journal of Physical Chemistry C, 2013, 117(1): 615–619. doi: 10.1021/jp306742p
[26]	WANG J S, MA C L, ZHU H Y, et al. Structural transition of BaF₂ nanocrystals under high pressure [J]. Chinese Physics C, 2013, 37(8): 088001. doi: 10.1088/1674-1137/37/8/088001
[27]	WANG X, ZHUANG J, PENG Q, et al. A general strategy for nanocrystal synthesis [J]. Nature, 2005, 437(7055): 121–124. doi: 10.1038/nature03968
[28]	ZHANG X M, QUAN Z W, YANG J, et al. Solvothermal synthesis of well-dispersed MF₂ (M = Ca, Sr, Ba) nanocrystals and their optical properties [J]. Nanotechnology, 2008, 19(7): 075603. doi: 10.1088/0957-4484/19/7/075603
[29]	BIRCH F. Finite strain isotherm and velocities for single-crystal and polycrystalline NaCl at high pressures and 300 °K [J]. Journal of Geophysical Research, 1978, 83(B3): 1257–1268. doi: 10.1029/JB083iB03p01257
[30]	WANG J S, MA C L, ZHOU D, et al. Structural phase transitions of SrF₂ at high pressure [J]. Journal of Solid State Chemistry, 2012, 186: 231–234. doi: 10.1016/j.jssc.2011.12.015
[31]	HALL E O. The deformation and ageing of mild steel: Ⅲ discussion of results [J]. Proceedings of the Physical Society. Section B, 1951, 64(9): 747–753. doi: 10.1088/0370-1301/64/9/303
[32]	PETCH N J. The cleavage strength of polycrystals [J]. Journal of the Iron and Steel Institute, 1953, 174: 25–28.
[33]	QADRI S B, YANG J, RATNA B R, et al. Pressure induced structural transitions in nanometer size particles of PbS [J]. Applied Physics Letters, 1996, 69(15): 2205–2207. doi: 10.1063/1.117166
[34]	ANGEL R J. The high-pressure, high-temperature equation of state of calcium fluoride, CaF₂ [J]. Journal of Physics: Condensed Matter, 1993, 5(11): L141–L144. doi: 10.1088/0953-8984/5/11/001