Sensors and Actuators B 202(2014)1065–1069
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Sensors and Actuators B:
Chemical
j o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /s n
b
Luminescent properties of chromium(III)-doped lithium aluminate for temperature nsing
Xinyue Li,Guicheng Jiang,Shaoshuai Zhou,Xiantao Wei,Yonghu Chen,Chang Kui Duan,Min Yin ∗
Department of Physics,University of Science and Technology of China,Hefei 230026,China
a r t i c l e i n f o Article history:
Received 27February 2014
Received in revid form 11June 2014Accepted 15June 2014
Available online 21June 2014
Keywords:LiAl 5O 8:Cr 3+
Temperature-dependent luminescence Optical thermometry
a b s t r a c t
A ries of novel temperature-nsitive phosphors LiAl 5(1−x )O 8:x Cr 3+(x =0.001–0.012)are synthesized by combustion method.The phosphors can be efficiently excited by the whole wavelength range of the visible light,producing strong deepred emission,which can be assigned to the 2E →4A 2transition.The intensity,peak wavelength and decay lifetime of the emission are measured to vary strongly with temper-ature for all the samples.Especially,the decay lifetime change dramatically from 4.31ms to 0.38ms from 200K to 600K for the sample with x =0.002,which give a highest temperature nsitivity of −0.015ms K −1at 400K and a maximal relative nsitivity of 0.83%K −1at 447K.The results show that LiAl 5O 8:Cr 3+is promising for optical thermometry.
©2014Elvier B.V.All rights rerved.
化妆品有哪些品牌1.Introduction
Temperature-dependent properties are of particular impor-tance in various fields of science and technology [1].Since the conventional temperature nsors have suffered from a lot of limitations in many special situations such as intracellular envi-ronment in vivo [2,3],recently considerable attentions have been focud on the development of contactless temperature nsing bad on non-contact thermometry techniques,includ-ing IR thermography,optical pyrometry and Raman spectroscopy.Temperature-nsitive luminescent materials with high spatial and temperature resolution reprent a promising alternative to detect temperature accurately.In the past decades,many luminescent materials have been studied by measuring numerous parame-ters such as the fluorescence intensity ratio (FIR)[4,5],the peak wavelength,the fluorescence lifetime and the emission bandwidth.Among the suitable phosphors reported for their temperature n-sitivity are TiMg 2O 4:Mn 4+[1],La 2O 2S:Eu 3+[6,7],CaTiO 3:Pr 3+[1],La 2O 2S:Nd 3+[8],NaYF 4:Yb 3+,Er 3+[3,9]as well as NaLuF 4:Yb 3+,Ho 3+[10].
Trivalent chromium (Cr 3+)doped luminescent materials,owing to their unique optical properties,have attracted great interest in recent years [11,12],and a large amount of efforts have been invested on temperature-dependent properties of the Cr 3+doped
∗Corresponding author.Tel.:+8655163606912;fax:+8655163600817.E-mail address:yinmin@ (M.Yin).systems [13,14]in view of their potential application in temper-ature nsors.Referring to the Tanabe–Sugano diagram for Cr 3+in octahedral crystal fields [2],the luminescent properties depend critically on the crystal field strength,which has a decisive effect on the quence of the two lowest excited states.In high or inter-mediate crystal field,as in ruby and alexandrite [15,16],the lowest excited state is the 2E state identified with a narrow band emis-sion and relatively long lifetime.In the ca where Cr 3+ions lie in a weak crystal field,the lowest excited state is the 4T 2state,which is characterized by broadband emission with a short lifetime.Furthermore,the energy difference between the 2E and 4T 2states varies from one host to another,so do the temperature dependent properties.
Among various hosts,lithium aluminate (LiAl 5O 8)can rve as an ideal host for transition metal ions,owing to its excel-lent chemical and thermal stability.When Cr 3+is doped in the LiAl 5O 8crystal lattice,the value of Dq/B is clo to the criti-cal value (Dq/B =2.3),where the two emitting states lie at the point of crossover in the Tanabe–Sugano diagram,and the energy difference between the two lowest excited states 2E and 4T 2is small.Therefore,the temperature-dependent properties could be more pronounced than in other hosts.All the properties are favorable for LiAl 5O 8:Cr 3+as a prom
ising matrix for optical tem-perature nsor.To the best of our knowledge,the comprehensive temperature-dependent properties of LiAl 5O 8:Cr 3+,including the emission intensity,peak wavelength and decay lifetime,has not been reported.Therefore,in this work,the luminescence spec-troscopic investigation of chromium(III)-doped lithium aluminate
/10.1016/j.snb.2014.06.053
0925-4005/©2014Elvier B.V.All rights rerved.
1066X.Li et al./Sensors and Actuators B 202(2014)1065–1069
(LiAl 5O 8)phosphor is conducted by the excitation spectrum,the emission spectrum and the decay curves measurements.The purpo of this work is to discuss the temperature-dependent properties of LiAl 5O 8:Cr 3+bad on the intensity and the peak wavelength as well as the decay lifetime of the deepred emission at various temperatures,and its potential application in temperature nsing.
2.Experimental
A ries of LiAl 5(1−x )O 8:x Cr 3+(x =0.001–0.012)samples were synthesized by combustion method [17]via a highly exother-mic redox reaction between metal nitrates and organic fuels.All the c
hemicals were analytical-grade reagents and ud with-out further purification.The starting materials,including LiNO 3,Al(NO 3)3·9H 2O,Cr(NO 3)3·9H 2O,and urea,were mixed with the specified stoichiometric ratio.The mixture was ground in an agate mortar until it became a paste,and then transferred it into a muf-fle furnace preheated at 500◦C,where the paste was ignited and started to react with flame yielding voluminous products.After ground into powder,the samples were obtained.
The crystalline phas of the synthesized samples were char-acterized by an X-ray diffractometer (MAC Science Co.Ltd.MXP18AHF)using nickel-filtered Cu K ␣radiation ( =0.15418nm)in the 2Ârange from 10◦to 70◦.The excitation and emission spectra were recorded with a Hitachi 850Fluorescence Spectropho-tometer using a 150W xenon lamp as the excitation source.For the fluorescence lifetime measurements,a frequency-doubled Q-switched flash-pumped YAG:Nd lar with the pul duration of 10ns was ud,and the decay curves were recorded with a Tektronix TDS2024digital storage oscilloscope.A WC50helium compressor using copper as heat transfer media and a Lake Shore Model 321temperature controller were ud to control the tem-perature of the samples.3.Results and discussion 3.1.X-ray diffraction
The XRD patterns of the as-synthesized LiAl 5O 8:Cr 3+samples are shown in Fig.1.The diffraction p
eak positions of the samples match
10203040506070
JCPDS No.71-1736
x=1.2%
x=0.6%
x=0.1%
I n t e n s i t y (a .u .)
2θ(degree)
Fig.1.XRD patterns of the LiAl 5O 8:Cr 3+samples compared with LiAl 5O 8standard data JCPDS No.71-1736.
well with the standard data of LiAl 5O 8(JCPDS No.71-1736),and no cond pha is found when incorporating different amounts of Cr 3+ions as dopants,indicating that the pure cubic pha of LiAl 5
O 8is successfully synthesized via the combustion method.The fairly narrow full width at half maximum and inten diffraction peaks suggest the well crystallization of the samples.Pure cubic LiAl 5O 8crystallizes in an inver spinel structure,belonging to P4332(No.
212)space group symmetry with lattice parameter a =7.9080´˚A.
In LiAl 5O 8crystal lattice,there are two unequal aluminum site pos-itions,octahedral site and tetrahedral site.The octahedral site is occupied by the Li +and a fraction of Al 3+ions,associated with a long-range (1:3)ordering,and the remaining Al 3+ions are tetra-hedrally coordinated.When Cr 3+ions are introduced,no charge compensation is needed due to the equal electric charges of Cr 3+and Al 3+ions,and the transition metal ions prefer to substitute for Al 3+at sites of octahedral symmetry,for the crystal field sta-bilization energy of Cr 3+ions in octahedral sites is greater than in tetrahedral sites.Moreover,the lattice distortion by this substitu-tion can be negligible becau of the approximately equal ionic radii of Cr 3+and Al 3+ions [18].
400
500
600
0.0
八年级上册生物思维导图0.2
0.4
活跃股0.6
0.8
1.0(a)
Wavelength(nm)
N o r m a l i z e I n t e n s i t y (a .u .)
λem = 713.7 nm
650
700
750
800
(b)
λex = 554 nm
哀民生之多艰Fig.2.Excitation and emission of the LiAl 5O 8:0.6%Cr 3+samples.(a)Excitation spectrum monitored at 713.7nm.(b)Emission spectrum under 554nm excitation.
X.Li et al./Sensors and Actuators B 202(2014)1065–10691067
L i f e t i m e a t r o o m t e m p e r a t u r e (m s )
Doping concentration of Cr
3+
0.0
0.2
0.4
0.6
0.8
1.0
R e l a t i v e L u m i n e s c e n c e I n t e n s i t y
Fig.3.The dependences of the luminescence intensity and the luminescence life-time of the R 1line on the doping concentrations of the Cr 3+ions.The decay curves were measured using 532nm pul light of YAG:Nd lar as the exciting source.The solid line is just a guide to the eye.
3.2.Luminescence spectra
The excitation and emission spectra at room temperature for LiAl 5O 8:Cr 3+phosphor are prented in Fig.2.As shown in Fig.2(a),there are two broad excitation bands centered at 394nm and 554nm,which are assigned to the 4A 2→4T 1and 4A 2→4T 2spin-allowed transitions respectively.Notably,the phosphor can be excited by a wide range of visible light efficiently,and this makes the cheaper and compact light sources available for excitation,which is an excellent merit of temperature-nsitive luminescent phosphors for practical application.The emission spectrum under
excitation at 554nm in Fig.2(b)consists of two parts:a strong deepred emission peaking at 713.7nm and a weak narrow-line peaking at 700nm,which can be recognized as the character-istic R 1and R 2components of the crystal field R line of Cr 3+ions respectively [19],accompanied with a broadband emission extending from 650nm to 800nm.The R line is assigned to the spin-forbidden 2E →4A 2transition of Cr 3+ions at octahedral site,while the associated broad background emission originates mostly from the phonon-assisted sidebands [20].Moreover,the emission peak at around 730nm could be obrved in the emission spectrum,which is attributed to the strong exchange interactions in nearest neighbor Cr 3+–Cr 3+pairs [21].
Fig.3illustrates the dependences of the luminescence intensity and the fluorescence lifetime on the concentrations of the Cr 3+ions.It is noticed that the luminescence intensity of the R 1line enhances considerably with the addition of Cr 3+ions becau of the increas-ing of luminescent centers,and reaches the maximum,implying that 0.6%Cr 3+is an optimum doping concentration with maximal emission intensity,and then decreas gradually.The reason for the concentration quenching could be the enhanced non-radiative relaxation during energy migration among neighboring Cr 3+ions.Additionally,the decay times of the R 1line significantly decrea as the Cr 3+concentration increas.This is also due to the concentra-tion quenching,in consistent with the dependence of luminescence intensity on the concentrations of Cr 3+ions.3.3.Temperature-dependent properties
As prented in Fig.4,temperature significantly affects the lumi-nescence intensity of the R 1line associated with the 2E →4A 2transition.When rising the sample temperature from room tem-perature to 780K,the emission intensity of the R 1line decreas verely.On the contrary,the broad background emission is
R e l a t i v e I n t e n s i t y (a .u .)
Wavelength(nm)
Fig.4.Temperature dependence of the luminescence intensity of the LiAl 5O 8:0.6%Cr 3+sample.The inrted figure is the normalized intensity of the R 1-line as a function of temperature.
broadened and has a slight trend to ri.Finally,the R 1line disap-pears completely in a growing background of the phonon-assisted sidebands when temperature is high.The mechanism of the tem-perature dependence of the luminescence intensity is explained bad on the thermal quenching of excited 2E levels.As the tem-perature of the phosphor increasing,the efficiency of luminescence reduces due to opening up of competing non-radiative relaxation pathways.
Meanwhile,the influence of temperature on the R 1line spec-tral position is examined in Fig.5.Compared
with its position at 20K,the peak wavelength of the R 1line shifts to the red (the longer wavelength)with a rate of 0.009nm K −1.The temperature-induced shift of spectral line in crystals is primarily due to the interac-tion between electronic transition and phonons of the host lattice,ignoring the thermal expansion of the crystal lattice.The obrved red-shift of the R 1line as a function of temperature can be fitted by the following equation,as reported by veral authors for different materials [22,23].SE (cm
−1
)=˛
T T D
4
T D /T
x 3
e x −1
dx (1)
L i n e s h i f t (c m -1
)
Temperature(K)
Fig.5.The position shift of the R 1line with respect to its position at 20K.
1068X.Li et al./Sensors and Actuators B 202(2014)1065–1069
L i f e t i m e (m s )
Temperature(K)
0.0
0.2
0.4
0.6
0.8
R e l a t i v e S e n s i t i v i t y (% K -1
巢姓)
Fig.6.The lifetime of R 1line of the LiAl 5O 8:0.2%Cr 3+at various temperatures.
where ˛is the electron–phonon coupling coefficient,and T D is the
Debye temperature.The coefficient ˛is dependent on the covalency of the host lattice,and the stronger covalence could lead to a larger electron–phonon coupling coefficient ˛[24].Here the coefficient ˛is treated as an adjustable parameter derived from the best fitting of the experimental data.In Fig.5,the experimental data is shown by the black dot,while the theoretical curve following Eq.(1)is shown as the solid line.The experimental data can be fitted well with the theoretical equation,and the best fitted values of ˛and T D are 510cm −1and 700K,respectively.
What is more,the fluorescence decay time of the LiAl 5O 8:Cr 3+phosphor is found to be highly temp
erature-dependent as well,which is one of the most significant qualities for optical thermom-etry.For the measurements of the temperature dependence of the decay lifetime ,the LiAl 5O 8:0.2%Cr 3+sample is chon to be the reprentative sample,and the decay curves of the R 1emission show non-monoexponential character,and are best described by the stretched exponential function [25,26]as follows:I (t )=I 0exp −
t
ˇ
(2)
where I (t )is the luminescence intensity after the puld excita-tion,and I 0is the luminescence intensity at t =0,respectively.The parameter gives a characteristic lifetime for the decay of the excited 2E states,which reprents a weighted average lifetime over the fast early rates and slow long-lived rates,since the sur-roundings of Cr 3+ions cannot be completely same in the crystal lattice and a slight bit of difference of the decay rates could lead to different lifetimes.The characteristic dispersion factor ˇ,ranging from 0to 1,reprents the degree to which the measured decay dif-fers from a purely exponential decay,who ˇ=1.The dependence on temperature of the lifetime of LiAl 5
O 8:Cr 3+has been investi-gated from 20K to 670K,and the derived lifetimes are prented in Fig.6,with ˇrange from 0.7to 0.9.In addition,no pha change is found during the measurement.
At low temperature below 200K,the lifetime is nearly constant.However,during the temperature range from 200K to 600K,it is obrved to decline dramatically with the rising of temperature,revealing that the fluorescence lifetime has a broad temperature nsitive extent,which is much wider than the range of 270–350K reported for YAlO 3:Cr 3+[27].The corresponding lifetimes drop from 4.31ms to 0.38ms from 200K to 600K.The experimental data fit well to an Arrhenius-type of equation [28]:1 =k 0+k 1exp − E RT
(3)
where parameter is the average lifetime,k 0is the temperature independent decay rate for the deactivation of the excited-state,k 1reprents the pre-exponential factor, E is the energy difference between the emitting state and an upper deactivating state,and R is the gas constant.The fitting parameters obtained are k 0=0.23s −1,k 1=135s −1and E =21.3KJ mol −1,and the correlation coefficient (r 2)is higher than 0.996.It is worth mentioning that the accept-able fitting range as a function of temperature is more extensive in comparison with that of ruby [29].Furthermore,the relativ
e change of the lifetime with respect to temperature variation S is a very important parameter for temperature thermometry,which is given by:血泊
S = 1 d dT
(4)
This equation suggests that a smaller temperature variation can be
obtained with a larger S at a given temperature.
The obrved decrea in lifetime with the elevation of temper-ature can be attributed to the following aspects.The energy of the 2E state and the 4T 2
state are clo enough to keep the thermal
equilibrium between them.At low temperature,the population of 2E state,who decay rate is slow due to the spin-forbidden transi-tion,has the dominant advantage,thus relatively long decay times could be obrved.However,with the increa of temperature,the thermal population of the upper 4T 2state,who decay rate is fast due to the spin-allowed transition,plays a more important role,which r
esults in a decrea of the fluorescence lifetime.Meanwhile,the enhanced probability of temperature dependent vibronic tran-sition can account for the decrea of lifetime.Furthermore,at even higher temperatures,a substantial increa in non-radiative relax-ation rate will significantly speed up the decay of the excited 2E state.
Bad on the data showed in Fig.6,the temperature nsitivity of the lifetime can be evaluated,and the average temperature n-sitivity is about −0.01ms K −1with the highest of −0.015ms K −1at 400K,and the maximal relative nsitivity S is 0.83%K −1at 447K.Therefore,the systematic work on the temperature-dependent properties of the LiAl 5O 8:Cr 3+phosphor has been detailedly inves-tigated through the emission intensity,peak wavelength and decay lifetime of the R 1line,which suggests that it could be an excellent alternative to the few middle range temperature phosphors with a broad temperature range and high nsitivity.4.Crystal field and Racah parameters
In our prent work,the crystal field splitting parameter and Racah parameters of the LiAl 5O 8:Cr 3+phosphor have been investi-gated.The value of the crystal field parameter Dq could be obtained from the energy transition between the excited 4T 2state and the ground 4A 2state [22,30].Dq =
E (4T 2)10
(5)
The value of the Racah parameters B and C are calculated from the equations as follows:B =Dq
( E/Dq)2
−10( E/Dq)
15(( E/Dq)−8)
(6)
C =
智商
E (2E )B −7.9+1.8B
Dq
B
3.05
(7)
where E =E (4T 1)−E (4T 2),reprenting the energy difference between the 4T 2and 4T 1states.The value of the crystal field param-eter Dq and the Racah parameters B and C are calculated to be Dq =1805cm −1,B =737cm −1and C =2863cm −1,respectively.Fur-thermore,the value of Dq/B is evaluated as 2.45,which is consistent
X.Li et al./Sensors and Actuators B202(2014)1065–10691069
with the value of the previous reported work[12],implying that the Cr3+ions in the LiAl5O8matrix lie at sites with intermediate crys-talfield.Obviously,it can be inferred that the energy difference between the two excited2E and4T2states is small.
5.Conclusion
In summary,a ries of LiAl5O8:Cr3+have been successfully synthesized via the combustion method,and then structural and photoluminescent characterizations have been carried out.Strong deepred emission,being assigned to R1line of Cr3+,has been obrved under a broad wavelength range of visible-light exci-tation.The intensity,peak wavelength and decay lifetime of the luminescenc
e vary strongly with temperature for all the samples. In particular,the lifetime of the R1line for the sample LiAl5O8:x Cr3+ (x=0.002)have been measured in detail for temperature nsing.
A high average temperature nsitivity of−0.01ms K−1is obtained in a broad temperature range of200–600K,with a maximum of−0.015ms K−1at400K and a maximal relative nsitivity of 0.83%K−1at447K.Our results show that LiAl5O8:Cr3+is very promising for high-nsitive optical thermometry.
Acknowledgments
This work wasfinancially supported by the National Key Basic Rearch Program of China(No.2013CB921800),the National Natural Science Foundation of China(Nos.11374291,11204292, 11274299and11311120047),the Fundamental Rearch Funds for the Central Universities(WK2030020021)and Anhui Provincial Natural Science Foundation(Grant No.1308085QE75). References
[1]J.Brübach,T.Kisl,M.Frotscher,M.Euler,B.Albert,A.Dreizler,A survey of
phosphors novel for thermography,J.Lumin.131(2011)559–564.
[2]S.M.Borisov,K.Gatterer, B.Bitschnau,I.Klimant,Preparation and char-
acterization of chromium(III)-activated yttrium aluminum borate:a new thermographic phosphor for optical nsing and imaging at ambient tempera-tures,J.Phys.Chem.C114(2010)9118–9124.
[3]S.S.Zhou,K.M.Deng,X.T.Wei,G.C.Jiang,C.K.Duan,Y.H.Chen,M.Yin,Upconver-
sion luminescence of NaYF4:Yb3+,Er3+for temperature nsing,Opt.Commun.
291(2013)138–142.
[4]W.Xu,X.Y.Gao,L.J.Zheng,Z.G.Zhang,W.W.Cao,An optical temperature nsor
bad on the upconversion luminescence from Tm3+/Yb3+codoped oxyfluoride glass ceramic,Sens.Actuators B173(2012)250–253.
[5]W.Xu,H.Zhao,Y.X.Li,L.J.Zheng,Z.G.Zhang,W.W.Cao,Optical tempera-
ture nsing through the upconversion luminescence from Ho3+/Yb3+codoped CaWO4,Sens.Actuators B188(2013)1096–1100.
[6]S.V.Yap,R.M.Ranson,W.M.Cranton,D.C.Koutsogeorgis,G.B.Hix,Temperature
dependent characteristics of La2O2S:Ln[Ln=Eu,Tb]with various Ln concen-trations over5–60◦C,J.Lumin.129(2009)416–422.
[7]L.M.Coyle,M.Gouterman,Correcting lifetime measurements for temperature,
Sens.Actuators B61(1999)92–99.
[8]G.C.Jiang,X.T.Wei,S.S.Zhou,Y.H.Chen,C.K.Duan,M.Yin,Neodymium doped
lanthanum oxysulfide as optical temperature nsors,J.Lumin.152(2014) 156–159.
[9]W.Yu,W.H.W.S.Xu,S.Zhang,Temperature-dependent upconversion lumines-
cence and dynamics of NaYF4:Yb3+/Er3+nanocrystals:influence of particle size and crystalline pha,Dalton Trans.43(2014)6139–6147.
[10]S.S.Zhou,S.Jiang,X.T.Wei,Y.H.Chen,C.K.Duan,M.Yin,Optical thermometry
bad on upconversion luminescence in Yb3+/Ho3+co-doped NaLuF4,J.Alloys Compd.588(2014)65
4–657.
北京旅游必去十大景点[11]G.P.Dong,X.D.Xiao,M.Y.Peng,Z.J.Ma,S.Ye,D.D.Chen,H.J.Qin,G.L.Deng,
Q.M.Liang,J.R.Qiu,Synthesis and optical properties of chromium-doped spinel hollow nanofibers by single-nozzle electrospinning,RSC Adv.2(2012) 2773–2782.
[12]V.Singh,R.P.S.Chakradhar,J.L.Rao,H.Y.Kwak,Characterization,EPR and pho-
toluminescence studies of LiAl5O8:Cr phosphors,Solid State Sci.11(2009) 870–874.
[13]Y.R.Shen,K.L.Bray,Effect of pressure and temperature on the lifetime of Cr3+
in yttrium aluminum garnet,Phys.Rev.B56(1997)10882–10891.[14]Z.Y.Zhang,K.T.V.Grattan,A.W.Palmer,Temperature dependences offluo-
rescence lifetimes in Cr3+-doped insulating crystals,Phys.Rev.B48(1993) 7772–7778.
[15]Y.Kitaoka,K.Nakamura,T.Akiyama,T.Ito,M.Weinert,A.J.Freeman,Excited Cr
impurity states in Al2O3from constraint density functional theory,Phys.Rev.
B87(2013)205113.
[16]K.Izumi,S.Miyazaki,S.Yoshida,T.Mizokawa,E.Hanamura,Optical properties
of3d transition-metal-doped MgAl2O4spinels,Phys.Rev.B76(2007)075111.
[17]S.S.Pitale,V.Kumar,I.M.Nagpure,O.M.Ntwaeaborwa,E.Coete,H.C.Swart,
Cathodoluminescent properties and surface characterization of bluish-white LiAl5O8:Tb phosphor,J.Appl.Phys.109(2011)013105.
[18]C.N.Avram,M.G.Brik,A.S.Gruia,Theoretical calculations of energy levels
scheme of Cr3+-doped LiAl5O8spinel,Optoelectron.Adv.Mater.–Rapid Com-mun.4(2010)1127–1130.
[19]T.Abritta,N.T.Melamed,J.Marianeto,F.Desouzabarros,The optical properties
of Cr3+in LiAl5O8and LiGa5O8,J.Lumin.18–19(1979)179–182.
[20]F.Liu,W.Z.Yan,Y.J.Chuang,Z.P.Zhen,J.Xie,Z.W.Pan,Photostimulated near-
infrared persistent luminescence as a new optical read-out from Cr3+-doped LiGa5O8,Sci.Rep.3(2013)1554.
[21]B.D.Maccraith,T.J.Glynn,G.F.Imbusch,J.P.Remeika,D.L.Wood,Exchange
interactions in nearest-neighbor Cr3+ion pairs in LiGa5O8:Cr3+,Phys.Rev.B 25(1982)3572–3575.
[22]G.Dominiak-Dzik,W.Ryba-Romanowski,M.Grinberg,E.Beregi,L.Kovacs,
Excited-state relaxation dynamics of Cr3+in YAl3(BO3)4,J.Phys.:Condens.Mat-ter.14(2002)5229–5237.
[23]Y.Zhydachevskii,D.Galanciak,S.Kobyakov,M.Berkowski,A.Kami´nska,A.
Suchocki,Y.Zakharko,A.Durygin,Photoluminescence studies of Mn4+ions in YAlO3crystals at ambient and high pressure,J.Phys.:Condens.Matter.18 (2006)11385–11396.
[24]W.C.Zheng,B.X.Li,G.Y.Feng,H.G.Liu,Rearch on the thermal shifts and
electron-phonon coupling parameters of R-line for Cr3+and Mn4+ions in YAlO3 crystals,J.Lumin.138(2013)214–217.
[25]J.Linnros,N.Lalic,A.Galeckas,V.Grivickas,Analysis of the stretched exponen-
tial photoluminescence decay from nanometer-sized silicon crystals in SiO2,J.
Appl.Phys.86(1999)6128–6134.
[26]H.L.Wen,P.A.Tanner,Energy transfer and luminescence studies of Pr3+,Yb3+
co-doped lead borate glass,Opt.Mater.33(2011)1602–1606.
[27]H.Uchiyama,H.Aizawa,T.Katsumata,S.Komuro,T.Morikawa,E.Toba,Fiber-
optic thermometer using Cr-doped YAlO3nsor head,Rev.Sci.Instrum.74 (2003)3883–3885.
[28]H.S.Peng,M.I.J.Stich,J.B.Yu,L.N.Sun,L.H.Fischer,O.S.Wolfbeis,Lumines-
cent europium(III)nanoparticles for nsing and imaging of temperature in the physiological range,Adv.Mater.22(2010)716–719.
[29]Y.L.Hu,Z.Y.Zhang,K.T.V.Grattan,A.W.Palmer,B.T.Meggitt,Ruby-bad
decay-time thermometry:effect of probe size on extended measurement range (77–800K),Sens.Actuators A63(1997)85–90.
[30]K.P.O’donnell,A.Marshall,M.Yamaga,B.Henderson,B.Cockayne,Vibronic
structure in the photoluminescence spectrum of Cr3+ions in garnets,J.Lumin.
42(1989)365–373.
Biographies
Xinyue Li was born in Hebei,China in1990.She is currently pursuing her Ph.D. under the supervision of Prof.Yin and Prof.Duan,and her rearch is focud on the luminescent materials and their luminescent properties for the application on temperature nsor.
Guicheng Jiang was born in Jilin,China in1984.He received the Ph.D.in University of Science and Technology of China in2012.Now he is a post doctor in USTC,and his rearch is on the nano-sized upconversion luminescent materials.
Shaoshuai Zhou was born in Shandong,China in1988.He is currently pursuing his Ph.D.under the su
pervision of Prof.Yin and Prof.Duan,and his rearch is mainly on the upconversion luminescent materials.
Xiantao Wei was born in Shanxi,China in1982.He received the Ph.D.in University of Science and Technology of China in2010.His rearch is mainly on the mechanism of luminescence dynamics.
Yonghu Chen was born in Gansu,China in1974.He received the Ph.D.in University of Science and Technology of China in2002.He is an associate professor in USTC, and his current rearch is mainly on the long-persistent luminescent materials.
Chang-kui Duan was born in Anhui,China in1973.He received the Ph.D.in Univer-sity of Science and Technology of China in1998.He is a professor in USTC,and his current rearch is mainly on theoretical rearch of solid light-emitting materials and solid physics-bad quantum computing system.
Min Yin was born in Anhui,China in1960.He received the Ph.D.in University of Science and Technology of China in1995.He is a professor in USTC,and his current rearch is mainly on luminescent materials doped with rare earth ions.
