Jou nal o Non-C ys alline Solids 601 (2023) 122050
A ailable online 28 No embe 2022
0022-3093/© 2022 The Au ho (s). Published by Else ie B.V. This is an open access a icle unde he CC BY license (h p://c ea i ecommons.o g/licenses/by/4.0/).
Op ically ac i e nano-glass-ce amic coa ings o Nd
3+
doped-80SiO
2
-20LaF
3
p epa ed by he p e-c ys allized nanopa icles sol-gel ou e
Ma ía Eugenia C uz
a
,
*
, Joaquín Fe n´
andez
b
, Alicia Du ´
an
a
, Rolindes Balda
c
,
d
, Yolanda Cas o
a
a
Ins i u o de Ce ´
amica y Vid io, CSIC, Mad id, Spain
b
Donos ia In e na ional Physics Cen e (DIPC) 20018 San Sebas ian, Spain
c
Dep . Física Aplicada, Escuela Supe io de Ingenie ía, Uni e sidad del País Vasco (UPV-EHU), 48013 Bilbao, Spain
d
Cen o de Física de Ma e iales, (CSIC-UPV/EHU), 20018 San Sebas ian, Spain
ARTICLE INFO
Keywo ds:
Glass-ce amics
Pho onics
Sol-gel
Neodymium
Ac i e coa ings
ABSTRACT
T anspa en oxy luo ide glass-ce amic (OxGCs) coa ings wi h composi ion 1.2Nd
3+
80SiO
2
- 20LaF
3
we e p e-
pa ed ollowing a sol-gel ou e labelled “p e-c ys allized nanopa icles ou e”. OxGCs a e anspa en ma e ials
composed by one o mo e luo ide nanoc ys als in a glass ma ix. OxGCs ha e been p epa ed by sol-gel wi h
encou aging esul s in powde s and bulk glass-ce amics bu no in coa ings. In he p esen wo k, aqueous sus-
pensions o LaF
3
nanopa icles doped wi h Nd
3+
we e p epa ed by chemical ou e and hen inco po a ed in o a
silica sol o ob ain 1.2Nd
3+
doped-80SiO
2
-20LaF
3
pa icula e sols. Nd
3+
-LaF
3
suspensions a e cha ac e ized by
XRD, HRTEM, and XRF e ealing he p esence o LaF
3
as he unique c ys alline phase. Then, 1.2Nd
3+
-80SiO
2
-
20LaF
3
coa ings we e p epa ed by dip-coa ing and cha ac e ized by XRD, FTIR, and Ellipsome y. Pho o-
luminescence measu emen s we e pe o med o LaF
3
nanopa icles and OxGCs coa ings, con i ming he p es-
ence o Nd
3+
in he nanoc ys als and showing well-s uc u ed c ys alline-like emission spec a wi h li e imes o
520 and 440 µs espec i ely.
1. In oduc ion
T anspa en glass-ce amics (GC) [1–3] doped wi h a e ea h (RE)
ions ha e ecei ed ex ensi e a en ion du ing he las decades due o
hei a ied applica ions as solid-s a e lase s, ibe ampli ie s and
unable lase s among hem [4–6]. GCs p esen p ope ies simila o glass
as he excellen mechanical, he mal and elec ochemical s abili y [2,7,
8]. These p ope ies a e combined wi h hose o single c ys al as an
e ec i e op ical media o ligh p opaga ion and luminescence
enhancemen [1,9–11]. Mo eo e , GCs a e anspa en om he isible
o he nea -in a ed egion as well as compa ible wi h op ical echnol-
ogy. In pa icula , oxy luo ide glass-ce amics (OxGCs), whe e he c ys-
alline phase consis s o one o mo e luo ide c ys al phases, show
in e es ing op ical p ope ies. Fluo ide c ys als p esen low maximum
phonon ene gy (300-450 cm
−1
) and low e ac i e index compa ed o
oxides ha can be bene icially used. Fu he mo e, when RE a e used as
dopan s, he c ys al s uc u e o luo ides educes he p obabili ies o
mul ipho on elaxa ion, esul ing in high luminescence e iciencies [12].
The adi ional and mos used me hod o p epa e OxGCs is he mel -
quenching (MQ). By MQ, c ys als g ow du ing con olled hea - ea men
o he pa en glass a empe a u es close o hei ansi ion ange [10]. In
he pionee ing wo k o Wang and Ohwaki [13], he p epa a ion o
E
3+
-Yb
3+
codoped- OxGCs by mel ing-quenching was epo ed wi h
highly anspa en ma e ial wi h good op ical p ope ies. These OxGCs
showed a ound 100 imes mo e e icien luminescence han he pa en
glass. Howe e , RE ions a e loca ed no only in he c ys al phase, bu
hey a e also usually ound in he amo phous phases, only low ac ions
o luo ide being able o be inco po a ed. In addi ion, mos s udies o
OxGCs p epa ed by MQ a e ocused in he p epa a ion o bulk ma e ials
con aining many di e en luo ide c ys al phases wi h p omising op ical
p ope ies [14–17]. RE doped OxGCs op ical ibe s showed excellen
esul s, se ing as ac i e ibe s o op ical elecommunica ion. The
esea ch and applica ion o op ical ibe s ha e become mo e and mo e
a ac i e [18,19].
Al hough OxGCs can be used o imp o e he luminescence esponse
o op ical de ices, he e a e impo an applica ions, as an imic obial
su aces o en i onmen al moni o ing sys ems based in coa ings [4,20,
21]. The possibili y o p epa e OxGCs as ilms would allow he c ea ion
o new ma e ials o u he applica ion in no el ields. Howe e , coa -
ings canno be ob ained by he adi ional mel -quenching me hod, and
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (M.E. C uz).
Con en s lis s a ailable a ScienceDi ec
Jou nal o Non-C ys alline Solids
jou nal homepage: www.else ie .com/loca e/jnonc ysol
h ps://doi.o g/10.1016/j.jnonc ysol.2022.122050
Recei ed 18 July 2022; Recei ed in e ised o m 17 No embe 2022; Accep ed 20 No embe 2022
Jou nal o Non-C ys alline Solids 601 (2023) 122050
2
al e na i e ou es mus be conside ed.
Sol-Gel (SG) is a we -chemical p ocess wi h bo om-up app oaches o
p oduce high homogeneous ma e ials by using empe a u es much
lowe (<500◦C) han hose used in mel -quenching. This p ocess con-
sis s on he hyd olysis and polycondensa ion o me al alkoxide p e-
cu so s such as e ae hyl o hosilica e (TEOS) in a sol en , ypically
alcohol, by adding wa e [22]. A e he polycondensa ion, he o ma-
ion o an open con inuous ne wo k, called gela ion, akes place, ol-
lowed by a u he densi ica ion. SG is a e sa ile p ocess o p epa e
bulk, powde , and coa ings. In he las h ee decades, SG was used o
p oduce OxGCs wi h encou aging esul s [23–25]. Du ing he las yea s,
OxGCs ha e been p epa ed by sol-gel ollowing he Fujiha a´s ou e
based on he mixing o he me al alkoxide sol wi h a solu ion o a e
ea h p ecu so s. Fujiha a e al. [26] p epa ed o he i s ime LaF
3
glass-ce amics coa ings by sol-gel. The au ho s desc ibed he LaF
3
c ys alliza ion du ing he hea - ea men , and he p epa a ion o ho-
mogenous LaF
3
coa ings. Fujiha a’s g oup also epo ed he p epa a ion
o SiO
2
-LaF
3
bulk samples and coa ings using e ae hyl o hosilica e
(TEOS) as silica p ecu so and i luo oace ic acid (TFA) as luo ide
sou ce (TFA ou e), al hough no op ical esul s a e p o ided. The syn-
hesis p ocess in ol es he decomposi ion o TFA a ound 300◦C, ol-
lowed by he o ma ion o luo ide nanoc ys als (NCs). Many OxGCs
we e p epa ed ollowing he TFA ou e, leading o di e en luo ide
phases [24,27,28]. Howe e , up o 2018, mos a icles epo ed he
p epa a ion o OxGCs wi h small nominal c ys al ac ions (up o 10%).
In he same pe iod, Go ni e al. [29] desc ibed he c ys alliza ion p ocess
o OxGCs by sol-gel and concluded ha a hea - ea men o 1min is
enough o ob ain a sui able c ys alliza ion in he silica ma ix. GlaSS
g oup ha e also epo ed he p epa a ion, o he i s ime, o OxGCs
wi h an ac i e phase amoun o 18% mola o LaF
3
calcula ed by Rie -
eld [30]. La e , his g oup p epa ed OxGCs con aining GdF
3
, NaLaF
4
o
KLaF
4
NCs wi h 20% con en o ac i e phase [24,31,32]. E en hough
he luminescen esul s o his doped-OxGCs a e e y a ac i e, we e
limi ed o bulk o powde s. OxGCs we e also p epa ed as coa ings
ollowing his ou e bu du ing he densi ica ion o he coa ing by
hea - ea men , he c ys al g ow h is inhibi ed esul ing in c ys als
smalle han 3 nm, hus a oiding he ull inco po a ion o RE in o hem,
and educing he e iciency o he op ical esponse [22,33].
Only a ew pape s desc ibed al e na i e sol-gel ou es o achie e
OxGCs coa ings wi h sui able op ical p ope ies. Fo example, Rod igues
e al. [34] epo ed he p epa a ion o LaF
3
-SiO
2
coa ings by dispe sing
Eu
3+
-doped LaF
3
/LaOF NPs in o a silica sol by spin coa ing. Howe e ,
he p esence o LaF
3
was no con i med and luminescence measu e-
men s did no show he emission o Eu
3+
, likely due o he low quan i y
o NPs inco po a ed in he silica ma ix.
GlaSS´s g oup epo ed an al e na i e ou e, labelled as “P e-c ys-
allized nanopa icles ou e” [35] based on he p e ious syn hesis o
c ys alline luo ide NP aqueous suspensions ha a e subsequen ly
inco po a ed o a silica sol [36]. By his way, silica ac s as hos ma ix o
NCs o known mo phology and size, he densi ica ion o he ma ix no
a ec ing he NC g ow h. The syn hesis o s able LaF
3
aqueous NPs sus-
pensions was s udied in de ail using di e en su ac an s and dispe san s
[37–39]. In a p e ious wo k, C uz e al. [36] epo ed he p epa a ion o
Nd
3+
doped-80SiO
2
-20LaF
3
oxy luo ide glass-ce amic powde s wi h
encou aging pho onic esul s. The au ho s s udied he s abili y o he
LaF
3
NPs in o he silica ma ix be o e and a e he hea - ea men a
450◦C. The esul s e ealed a p omising me hod o p oduce s able
luo ide NP suspensions and hei inco po a ion in o a silica sol. Thus,
he aim o his wo k is he p epa a ion o Nd
3+
doped 80SiO
2
-20LaF
3
coa ings wi h e icien luminescence ollowing he “p e-c ys allized
nanopa icles ou e” p ese ing he p ope ies o Nd
3+
in LaF
3
c ys al.
This syn hesis ou e p o ed o be e y e icien o ob aining highly
c ys alline Nd
3+
-LaF
3
NPs wi h highe luminescence emission han hose
epo ed up o now.
2. Ma e ials and Me hods
2.1. Syn hesis o Nd
3+
-LaF
3
aqueous suspensions
NP suspensions wi h composi ion xNd
3+
-LaF
3
(whe e x=0, 0.9, 1.2
and 1.5 mol%Nd
3+
) we e p epa ed by mixing lan hanum chlo ide
(LaCl
3
, Alpha Aesa ), ammonium luo ide (NH
4
F, Me ck) and neodym-
ium ace a e (NdAc
3
, Me ck) in s oichiome ic concen a ions wi h
deionized wa e o each a La
3+
concen a ion o 0.04M. The suspen-
sions we e main ained a 75◦C o 1.5, 2, 4, 8 and 24 h, espec i ely. The
suspensions we e labelled as -XNd
3+
-LaF
3
whe e X is he mol% o Nd
and he s i ing ime. Then, poly inyl py olidone (PVP, Me ck) was
inco po a ed o 0.04M NPs suspensions a 10 w .% in ela ion o LaF
3
.
The suspensions we e concen a ed using a o a y e apo a o (R-210
wi h acuum pump V-700, Buchi) up o a concen a ion o 0.25M.
2.2. Cha ac e iza ion o Nd
3+
-LaF
3
aqueous suspensions
The 0.04M and 0.25M -XNd
3+
-LaF
3
suspensions we e cen i uged a
6000 pm o 5 min, and he esul ed powde s insed wi h deionized
wa e ; he p ocess was epea ed h ee imes. The powde s we e u he
d ied a 75◦C o 12h and hea ea ed a 450◦C o 6h in o de o emo e
he PVP [36].
Powde s wi h composi ion 1.5h-1.2Nd
3+
-LaF
3
, 2h-1.2Nd
3+
-LaF
3
, 4h-
1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
and, 24h-1.2Nd
3+
-LaF
3
we e cha ac-
e ized by X-Ray di ac ion using an X- ay powde di ac ome e (D8
ad ance, B uke ) wo king wi h CuK
α
adia ion (λ=1.5406 A). The
di ac ion pa e ns we e acqui ed in he ange 10◦<2Ɵ<70◦wi h a s ep
o 0.03◦. The c ys alli e size was calcula ed by using he Sche e ´s
equa ion, Eq. (1).
Dhkl =Kλ
β2−b2−cosθ
√(Equa ion 1)
whe e Dhkl is he calcula ed c ys alli e size, K=0.94 o sphe ical c ys-
als, θ is he B agg angle and β is he ull wid h o he di ac ion peak a
hal maximum in ensi y (FWHM). The ins umen al b oadening was
included as b [30,40]. The i s we e pe o med using he o igin so wa e
and he pseudo-Voig unc ion.
The Williamson-Hall (W-H) plo was also used o es ima e he size
and s ain b oadening by conside ing he peak wid h as a unc ion o 2θ.
The W-H plo was pe o med calcula ing he s ain (E) o each peak o
he XRD pa e n using he Eq. (2). The Williamson–Hall plo (β cosθ) s.
(4sinθ) was pe o med using he D
hkl
da a and E alues ollowed Eq. (3).
A linea eg ession o each plo was gene a ed; he s ain componen was
ob ained om he slope and he pa icle size om he y-in e cep [41].
E=β
4cosθ(Equa ion 2)
βcosθ =Kλ 1
Dhkl +4Esinθ (Equa ion 3)
High Resolu ion T ansmission Elec on Mic oscopy (HRTEM) was
used o cha ac e ize 2h-1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
and 24h-
1.2Nd
3+
-LaF
3
NPs suspensions d ied a 75◦C o 12 h and hea - ea ed a
450◦C o 6h. The powde s we e e-dispe sed in e hanol ollowed by
d opping on a ca bon-coa ed coppe g id (Lacey Ca bon, LC-200-Cu 25/
pk). HRTEM images we e aken om HRTEM-JEO 2100 mic oscope and
p ocessed using he open-sou ce ImageJ ® so wa e. All he la ice pa-
ame e s o LaF
3
we e de e mined h ough he elec on di ac ion
pa e n.
X-Ray Fluo escence spec oscopy was used o iden i y he eal
amoun o Nd
3+
p esen in he 1.5h- 1.2Nd
3+
-LaF
3
, 2h-1.2Nd
3+
-LaF
3
,
4h-1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
and, 24h-1.2Nd
3+
-LaF
3
powde s
d ied a 75◦C o 12h and hea ea ed a 450◦C o 6h. The analysis was
done using a PANanaly ical spec ome e employing Li
2
B
4
O
7
as
e e ence.
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
3
1.5h-1.2Nd
3+
-LaF
3
, 4h-1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
, and 24h-
1.2Nd
3+
-LaF
3
and 2h- XNd
3+
-LaF
3
(X=0.9, 1.2 and 1.5 mol%) powde s
ob ained om NP suspensions d ied and hea - ea ed o 6h a 450◦C
we e compac ed by uniaxial p essing o 3 min a 1000 MP o lumi-
nescence analysis. Then, he samples we e exci ed wi h a unable Ti:
sapphi e ing lase (0.4 cm
−1
linewid h) in he 765– 920 nm spec al
ange.
The luo escence was collec ed and dispe sed by a 0.25 m mono-
ch oma o , and he signal was de ec ed by an ex ended IR Hamama su
H10330A-75 pho omul iplie and p ocessed by a lock-in ampli ie . The
decay imes we e pe o med by exci ing he samples wi h a Ti:sapphi e
lase pumped by a pulsed, equency-double Nd:YAG lase (9 ns pulse
wid h), and de ec ing he emission as desc ibed abo e. The pho o-
mul iplie ou pu was eco ded wi h a Tek onix oscilloscope. Mea-
su emen s we e pe o med a oom empe a u e.
2.3. Syn hesis o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
sols
Sols o composi ion 1.2Nd
3+
doped-80SiO
2
-20LaF
3
we e p epa ed
using e ae hyl o hosilica e (TEOS, Sigma Ald ich) and me hyl-
ie hoxysilane (MTES, ABCR) as silica p ecu so s in a mola a io o
50TEOS/50MTES. The as-p epa ed and concen a ed 2h-1.2Nd
3+
-LaF
3
aqueous suspension was mixed wi h he TEOS and MTES p ecu so s
unde con inuous s i ing a oom empe a u e. Hyd ochlo ic acid was
added unde igo ous s i ing and a e 5 min; he sol was imme sed in
an ice ba h o 15 minu es and hen, e hanol absolu e (E OH) was added.
2.4. Deposi ion and cha ac e iza ion o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings
Glass-ce amic coa ings we e p epa ed by dip-coa ing on glass-slides
subs a es (SLIU-010-050, Labox), a 25cm.min
−1
and using he 1.2Nd
3+
doped-80SiO
2
-20LaF
3
sol and he aqueous NPs suspension syn hesized
o 2h. In his pa , he app op ia e hea ea men p ocedu e was
selec ed, simila o he p ocess desc ibed in a p e ious pape [36].
Coa ings we e d ied a 180◦C o 3h and hen sin e ed a 450◦C o 1h.
Mul ilaye coa ings we e p epa ed by epea ing he dip-coa ing p ocess
o 2 and 3 imes.
The coa ings we e cha ac e ized by spec oscopic ellipsome y in he
ange o wa eleng h (λ) 350-950nm using a M- 2000UTM ellipsome e
(J.A. Woollam Co., Lincoln, NE, USA). The incidence angle a ied be-
ween 50◦ o 60◦and he acquisi ion ime was 10s. Da a modeling we e
pe o med using he Comple e EASE so wa e ( e sion 5.20, J.A. Woo-
lam Co.) and he Cauchy’s equa ion model, shown in Eq. (4).
N(λ) = A+B
λ2+C
λ4+D
λ6…(Equa ion 4)
Whe e A, B, C, D, e c. a e Cauchy’s coe icien s, and N he e ac i e
index. The 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings hea ea ed a
180◦C om 0 o 180 min we e sc aped and analyzed by Fou ie T ans-
o m In a ed Spec oscopy (FTIR). The esul s we e eco ded wi h a
Pe kin- Elme Spec um 100 FT-IR ins umen in he ange 4000-450
cm
−1
, wi h a esolu ion o 4 cm
−1
.
1.2Nd
3+
-80SiO
2
-20LaF
3
coa ings hea ea ed a 180◦C o 3 h and
sin e ed a 450◦C o 1h we e analyzed by G azing Incidence X-Ray
di ac ion (GI-XRD). GI-XRD spec a we e ob ained using a X-pe PRO
The a/2The a di ac ome e (Panaly ical). The 2θ scanning angle a -
ied om 20 o 60◦, and he s ep used was 0.04◦wi h a g azing angle o
0.5◦.
High Resolu ion T ansmission Elec on Mic oscopy (HRTEM) was
used o cha ac e ize he sc aped 1.2Nd
3+
-80SiO
2
-20LaF
3
hea ea ed a
180◦C o 3h and sin e ed a 450◦C o 1h. The sample p epa a ion and
image p ocessing ollowed he expe imen al se up desc ibed in Sec ion
2.2.
The s eady-s a e emission and exci a ion spec a and luminescence
decay cu es o he 1.2Nd
3+
doped- 80SiO
2
-20LaF
3
coa ings we e
pe o med by using he expe imen al se up desc ibed in Sec ion 2.2. The
coa ings we e exci ed wi h a unable Ti-sapphi e ing lase , and he
inciden beam o med a 25◦angle wi h he sample no mal. The emi ed
ligh was collec ed along he di ec ion pe pendicula o he coa ings.
3. Resul s and discussion
3.1. Cha ac e iza ion o -XNd
3+
-LaF
3
NPs
S able -1.2 Nd
3+
-LaF
3
NPs suspensions we e p epa ed a di e en
eac ion imes om 1.5 o 24h. A small amoun o each suspension was
d ied a 75 ◦C and hen hea ea ed a 450◦C o 6h o s udy he e o-
lu ion o he NPs wi h he eac ion ime. Fig. 1a shows he X- ay
di ac ion (XRD) pa e ns o -1.2Nd
3+
-LaF
3
-NPs powde s, aken in he
ange 20◦<2Ɵ<70◦. As obse ed, he XRD pa e ns show clea and
in ense peaks associa ed wi h he c ys alliza ion o LaF
3
as hexagonal
phase as unique phase, co esponding o he pa e n JCPDS 00-032-
0483. In he XRD, i is obse ed ha he in ensi y o he peaks in-
c eases wi h he eac ion ime. The c ys al size calcula ed using he
Sche e ´s equa ion and W-H equa ion a e shown in Table 1. Fo a e-
ac ion ime o 1.5h he c ys alli e size, calcula ed by Sche e equa ion is
a ound 10nm, inc easing sligh ly o 11, 12 and 14 nm o longe eac ion
imes 2h, 4h and 8h, espec i ely; he maximum c ys al size, 28nm, is
eached o 24h. Mo eo e , Fig. 1a shows he ampli ica ion o he double
peak co esponding o 23◦<2Ɵ<26◦. This double becomes mo e
de ined wi h he eac ion ime, eaching a good esolu ion a 24 h,
con i ming he ad ance o c ys allini y o longe eac ion imes [42].
The a e age pa icle size and mic o-s ain ha e also been calcula ed
using W–H equa ion. Fig. 1b shows he plo ing o W-H equa ion o -1.2
Nd
3+
-LaF
3
NPs wi h om 1.5 o 24h. The slope o he lines p o ides he
alue o he in insic s ain, and he in e cep gi es he a e age pa icle
size (Table 1). The au ho s epo ha he c ys alli e size and la ice
s ain inc ease wi h he peak wid h [43]. This di e ence is a ibu ed o
he ac ha Sche e ´s equa ion only conside s ha all he peak wid h o
de e mining he pa icle size, whe eas by W-H model he peak wid h has
wo con ibu ions (s ain +c ys alli e size) [44]. On he o he hand, he
s ain alues, shown in Table 1, sligh ly change om 1.5h-1.2Nd
3+
-LaF
3
NPs o 2h-1.2Nd
3+
-LaF
3
NPs ( om 0.0997 o 0.0927) indica ing a
simila a omic a angemen and mo phology. The s ain is dec eased
un il 0.0034 o NPs syn hesized du ing 4h, associa ed wi h he
comple ed o ma ion o elonga ed NPs. Mo eo e o 8h-1.2Nd
3+
-LaF
3
NPs, whe e ounded NPs s a ed o appea (shown in he HR TEM images
in Fig. 2) he s ain inc eased un il 0.0305, ela ed o he la ice s ain
co esponding o he mo phology change in he NPs. Finally, he la ice
s ain up o 0.0165 dec eases wi h he comple e o ma ion o ounded
NPs and he inc ease o c ys alliza ion.
Fig. 2 shows he HRTEM images o -1.2Nd
3+
-LaF
3
powde s and he
espec i e NPs size dis ibu ion g aphs o eac ion imes o =2, 8 and
24h and hea - ea ed a 450◦C. Fig. 2a and b show he 2h-1.2Nd
3+
-LaF
3
NPs wi h elonga ed o m, mainly nano- ods, along wi h some sphe ical
ones, ob ained by agglome a ion o nano- ods p ima y pa icles. The
a e age size o he sphe ical pa icles is 11 nm and, 13 nm o elonga ed
ones (Fig. 2c and d, espec i ely). These alues a e disco dan wi h hose
calcula ed by W-H plo (Fig. 1), p obably associa ed wi h he o ma ion
o polyc ys alline agg ega es, esul ing in NP sizes highe han he
c ys alli e sizes [43]. In he case o 8h-Nd
3+
-LaF
3
powde (Fig. 2e and ),
agg ega ed NPs g ow quickly eaching a mo e sphe ical shape compa ed
o 2h-1.2Nd
3+
-LaF
3
NPs, al hough elonga ed NPs and emain in mo e
amoun . The dimensionless shape ac o be ween ounded (R) and
elonga ed (E) NPs was calcula ed as R/E, Table 1. Fu he mo e, o e-
ac ion imes om 2h o 8 h, an inc emen in he pa icles size is no iced
o bo h shapes o NPs, om 14 nm o 25 nm o he elonga ed NPs and
om 11 o 16 nm o sphe ical ones. Fo eac ion ime o 24h, a comple e
ans o ma ion om elonga ed o ounded shapes is obse ed (Fig. 2i
and j). In his case, he medium size o he sphe ical NPs is a ound 25
nm. The ampli ica ion images and il e ing using he as Fou ie
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
4
ans o m (FFT) o 2h-1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
and
24h-1.2Nd
3+
- LaF
3
NPs a e shown in Fig. 2b, and j, e ealing he la ice
planes wi h a cons an spacing o 2.0Å, associa ed wi h (113) a omic
plane o LaF
3
hexagonal phase. Simila beha io was epo ed by Liu and
Chen [45], whe e LaF
3
NPs we e p epa ed by sal o- he mal eac ion,
obse ing he ans o ma ion om elonga ed o sphe ical shape wi h he
inc emen o syn hesis empe a u e. O he au ho s such as Vane se
e al. [42] epo ed he p epa a ion o LaF
3
by di e en ou es; in
pa icula , by co-p ecipi a ion ou e less c ys alline ma e ials wi h
mainly elonga ed shape we e ob ained while mo e c ys alline NPs wi h
ounded/ hexagonal shapes we e ob ained by hyd o he mal mic o-wa e
ea men . In gene al, he kine ic pa ame e s such as empe a u e o
eac ion ime a ec he mo phology and c ys al size o he LaF
3
NPs.
1.2Nd
3+
-LaF
3
powde s we e analyzed by X- ay luo escence spec-
oscopy o quan i y he eal amoun o Nd
3+
inco po a ed in o he LaF
3
NPs (FF). XRF measu emen s we e pe o med o 1.5h- 1.2Nd
3+
-LaF
3
,
2h-1.2Nd
3+
-LaF
3
, 4h-1.2Nd
3+
-LaF
3
, 8h-1.2Nd
3+
-LaF
3
and 24h-1.2Nd
3+
-
LaF
3
samples (Table 1). The analysis e eals ha he concen a ion o
Nd
3+
inco po a ed in he NPs depends on he eac ion ime. Fo a e-
ac ion ime o 2h, only 1.02 mol% o Nd
3+
has been inco po a ed in he
NPs ins ead o 1.2 mol%. Thus, he inco po a ion o Nd
3+
inc eases wi h
he eac ion ime, eaching a 100% (1.2 mol%) o 24h-1.2Nd
3+
- LaF
3
.
3.2. Luminescence p ope ies o Nd
3+
-LaF
3
NPs
To analyze he in luence o he eac ion ime on he luminescence,
he emission o 1.2 mol% Nd
3+
- doped LaF
3
NPs was ob ained o =1.5,
2, 4, 8, and 24 h. The
4
F
3/2
→
4
I
11/2
s eady-s a e luo escence spec a
we e pe o med a oom empe a u e by exci ing wi h a Ti:sapphi e
lase a 786 nm in esonance wi h he
4
I
9/2
→
4
F
5/2
,
2
H
9/2
abso p ion
band. As obse ed in Fig. 3a, he emission inc eases om 1.5 o 2 h and
hen signi ican ly dec eases as eac ion ime inc eases. The e o e, he
mos e icien emission co esponds o a eac ion ime o 2 h. As i is
e ealed in he sec ion be o e, in Table 1, he con en o Nd
3+
in he NPs
is inc eased om 0.95% o 1.2% when eac ion ime inc eases om 1.5h
o 24h. Pa icula ly, he sample co esponding o a eac ion ime o 24h
shows a eal con en equal o he nominal one (1.2%).
The obse ed luminescence beha io o eac ion imes longe han
2h can be a ibu ed o concen a ion quenching due o he high con en
o Nd
3+
in he NPs a long eac ion imes, as well as changes o Nd
3+
dis ibu ion wi h NPs mo phology. Thus, Nd
3+
-LaF
3
NPs suspension
p epa ed a a eac ion ime o 2h was iden i ied as he mos e icien and
selec ed o he es o s udies [46–48].
On he o he hand, he luminescence p ope ies o LaF
3
NPs p epa ed
wi h a eac ion ime o 2 h and di e en amoun o dopan (0.9, 1.2, and
1.5 mol% Nd
3+
) hea - ea ed a 450◦C-6h we e measu ed o de e mine
he op imum concen a ion o Nd
3+
. As obse ed in Fig. 3b he spec a
a e simila o he h ee samples. The peaks posi ion and linewid h do
no change when inc easing Nd
3+
concen a ion; howe e , he emission
in ensi y is educed o he sample doped wi h 1.5% indica ing he
p esence o non- adia i e p ocesses. These p ocesses p esen o con-
cen a ions highe han 1.2 mol% Nd
3+
a e also e lec ed in he li e ime
alues o he
4
F
3/2
s a e, educed om 520 µs o he sample doped wi h
1.2 mol% Nd
3+
o 439 µs o 1.5 mol%. The spec al ea u es o he
emission spec a oge he wi h he li e ime alue o 520 µs co espond o
Nd
3+
ions in LaF
3
c ys al con i ming he inco po a ion o he a e-ea h
ion in LaF
3
NCs.
Fig. 1. (a) XRD pa e ns and (b) W-H plo om he XRD o -1.2Nd
3+
-LaF
3
powde s p epa ed a di e en eac ion imes; =1.5, 2, 4, 8 and 24h, and hea - ea ed a
450◦C o 6h.
Table 1
C ys alli e size calcula ed by Sche e ´s equa ion and by W-H plo , s ain calcula ed om W-H plo , elonga ed and ounded pa icle size measu ed om HR-TEM images
and, ounded/elonga ed shape a io (R/E) wi h he inc emen o eac ion ime e ec i e inco po a ion o Nd
3+
in he LaF
3
NPs (FF).
C is alli e Size (nm) Nanopa icle size (nm)
Reac ion
ime (h)
Sche e Equa ion
(þ/- 0.1nm)
W-H Plo
(þ/- 0.1nm)
S ain Elonga ed Pa icle size
ob ained om HR-TEM (þ/-
0.5nm)
Rounded Pa icle size
ob ained om HR-TEM (þ/-
0.5nm)
Roundedl/
Elonga ed NPs
molNd
3þ
:
molLaF3
(R/E) (FF)
1.5 10 2.9 0.0997 – – 20 0.95
2 11 3 0.0927 16 11 — 1.02
4 12 3.12 0.0034 – – 55 1.035
8 14 4 0.0305 25 16 — 1.05
24 28 8 0.0165 – 25 100 1.2
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
5
3.3. Cha ac e iza ion o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings
Homogeneous and anspa en 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa -
ings, we e p epa ed a e he inco po a ion o he Nd
3+
-LaF
3
NPs sus-
pension syn hesized o 2h (2h-1.2Nd
3+
-LaF
3
). The coa ings we e
p epa ed by dip-coa ing in ai a mosphe e and oom empe a u e and
subjec ed o a he mal ea men a 180◦C ollowed by hea ing 450◦C/
1h. I is c ucial o selec he bes sin e ing condi ions o densi y he
coa ings and o comple ely emo e he PVP. The combus ion and
decomposi ion o he o ganic ma e mus occu be o e he densi ica ion
o he coa ings, o he wise he po ous en ap he PVP du ing he densi-
ica ion o he ne wo k a oiding he elimina ion o su ac an and
a ec ing he op ical p ope ies. In his pa , he app op ia e hea ea -
men p ocedu e was selec ed, simila o he p ocess desc ibed in a p e-
ious pape [36].
Fig. 4 shows he FTIR analysis o he sc aped 1.2Nd
3+
doped-80SiO
2
-
Fig. 2. (a) and (b) HR-TEM images o 2h-1.2Nd
3+
-LaF
3
NPs, (c) and (d) pa icle size dis ibu ion o ounded and elonga ed 2h-1.2Nd
3+
-LaF
3
NPs, espec i ely, (e)
and ( ) HR-TEM images o 8h-1.2Nd
3+
-LaF
3
2h NPs, (g) and (h) pa icle size dis ibu ion o ounded and elonga ed 8h-1.2Nd
3+
-LaF
3
NPs, espec i ely, (i) and (j) HR-
TEM images o 24h-1.2Nd
3+
-LaF
3
8h NPs and (k) pa icle size dis ibu ion o ounded 24h-1.2Nd
3+
-LaF
3
NPs. Selec ed a eas o elec on di ac ion (SAED) pa e ns
and c ys alline s uc u es wi h in e plana dis ances associa ed o hexagonal phase a e shown in each pai o pic u es.
Fig. 3. Room empe a u e emission spec a o he
4
F
3/2
→
4
I
11/2
ansi ion o (a) LaF
3
NPs doped wi h 1.2% Nd
3+
ob ained o =1.5, 2, 4, 8, and 24 h and (b) LaF
3
NPs doped wi h h ee di e en Nd
3+
mola concen a ions o =2h.
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
6
20LaF
3
coa ings hea ea ed a 180◦C a di e en sin e ing ime om
0 o 3 h. In he spec um o he sc aped coa ing d ied a oom empe -
a u e (Fig. 4; =0 h), a b oad peak a ound 3000-3500cm
−1
appea s
associa ed o –OH (3000-3500cm
-1
) o molecula wa e oge he wi h
small peaks assigned o CH
2
g oups (2978cm
−1
) om he emainde s o
PVP. This b oad band is also obse ed o coa ings ea ed a 180◦C
du ing 1 and 2h [49]. Howe e , a e 3h o hea ea men , he peaks
disappea indica ing he o al elimina ion o PVP. In conclusion, he hea
ea men condi ions selec ed was 180◦/3h ollowed by 450◦C/1h.
The e ec o s acking coa ings on he op ical p ope ies was also
in es iga ed. Homogeneous and c ack- ee mul ilaye coa ings we e
p epa ed by s acking a maximum o 3 laye s o 1.2Nd
3+
doped- 80SiO
2
-
20LaF
3
(Fig. 5a) by dipping. The mul ilaye sys em was cha ac e ized by
ellipsome y o ob ain he op ical cons an and he hickness o each
s acking coa ing. Fig. 5b shows he ellipsome e measu es oge he wi h
he i ed cu es using he Cauchy model. The measu e o he ellipso-
me ic angles Ψ and Δ is in good ag eemen wi h he calcula ed alues,
con i ming he quali y o he coa ings. Fig. 5c shows he linea inc e-
men o coa ing hickness wi h he numbe o coa ings, om 1.2 µm o
one laye o 2.9 µm o h ee coa ings. The e ac i e index was
measu ed using he Cauchy model and conside ing one, wo o h ee
s ack laye s depending on he numbe o laye s deposi ed. A alue o
1.44 a λ=700 nm we e ob ained in all he case.
Fig. 6a and b shows HR TEM images o he sc apped coa ing wi h
composi ion 1.2Nd
3+
doped-80SiO
2
-20LaF
3
. Fig. 6a and b shows elon-
ga ed and ounded NPs, espec i ely, bo h wi h simila mo phology and
size (13nm and 14nm, ounded and elonga ed NPs espec i ely) o hose
NPs shown in HR TEM images o he 2h-1.2Nd
3+
-LaF
3
NPs. The HRTEM
in e plana dis ance shown in Fig. 6a was de e mined 0.32nm, co e-
sponding o he la ice plane (111) o he hexagonal LaF
3
(JPCD 00-32-
0483). These esul s con i m he p esence o he 2h-1.2Nd
3+
-LaF
3
NPs
in o he silica ma ix o he 1.2Nd
3+
doped-80SiO
2
-20LaF
3
OxGCs
coa ing as well as he s abili y o he NPs h ough he whole p ocess.
Fig. 6c shows he XRD pa e n o he ee-laye s 1.2Nd
3+
doped-
80SiO
2
-20LaF
3
coa ing hea ea ed as desc ibed below. The lack o
de ini ion o he peaks is ela ed o he ac ha coa ings ha e been
p epa ed on soda-lime glasses and, o he hickness o he coa ing ha is
much lowe han ha o he subs a e. In he XRD pa e n he peaks
Fig. 4. FTIR analysis by sc aping he 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings
hea - ea ed a 180◦C a di e en ea men imes: 0h (black line), 1h ( ed line),
2h (blue line) and 3h (g een line).
Fig. 5. (a) Ellipsome y cha ac e iza ion o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings wi h 1, 2 and 3 laye -by-laye assembly. Fi ing pe o med wi h Cauchy laye
model (dashed lines) o he ellipsome ic angle Ψ in he ange o 450nm<λ<900nm. (b) Va ia ion o he coa ing hickness as a unc ion o he numbe o laye s
deposi ed. (c) T anspa en iple-laye 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ing a e hea ea men a 180◦C o 3h and 450◦C o 1h.
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
7
associa ed o he hexagonal phase o LaF3 JCPDS 00-032-0483 a e
shown. The XRD pa e ns e eals he p esence o LaF
3
NPs inco po a ed
in o he OxGCs coa ing and i is possible o obse e ha he mos in ense
peak, co esponding o 2θ=27.45◦is associa ed o he plane (111), he
same obse ed in HR TEM images.
3.4. Luminescence p ope ies o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings
Once he op imum Nd
3+
concen a ion and eac ion ime we e
selec ed, he luminescence p ope ies o anspa en coa ings o 1.2Nd
3+
doped-80SiO
2
-20LaF
3
hea - ea ed 3h a 180◦C and 1h a 450◦C we e
measu ed. Fig. 7a shows, as an example, he emission and exci a ion
spec a o a anspa en coa ing p epa ed wi h wo laye s. The emission
spec um, like ha ob ained o he NPs, shows wo main peaks a
a ound 1047 and 1063 nm. This spec um con i ms ha Nd
3+
ions a e in
he LaF
3
NCs in he coa ings [46,50]. The emission (Fig. 7a) was ob-
ained by exci ing a 786 nm, he mos in ense peak in he exci a ion
spec um (Fig. 7b). The exci a ion spec um pe o med in he 775-890
nm ange by collec ing he luminescence a he maximum o he emis-
sion shows sha p peaks cha ac e is ics o he exci a ion spec um o
Nd
3+
in LaF
3
NCs [46]. Simila esul s a e ob ained o he h ee laye s
coa ings (no shown).
Fu he e idence o he p esence o Nd
3+
ions in he NCs in he
coa ings is p o ided by he luo escence decay cu es o he
4
F
3/2
le el.
Fig. 8 shows he expe imen al decay o he 1.2Nd
3+
doped-80SiO
2
-
20LaF
3
coa ing ob ained unde exci a ion a 786 nm and collec ing he
luminescence a 1063 nm. The decay can be desc ibed o a good
app oxima ion by a single exponen ial unc ion wi h a li e ime o 440
μ
s,
sho e han ha ob ained o he NPs. The expe imen al decay co e-
sponding o Nd
3+
in LaF
3
NPs is also ep esen ed in Fig. 8 ( ed line). This
educ ion o he li e ime canno be a ibu ed o he p esence o PVP,
ully elimina ed a e 3h a 180◦C (Fig. 4), a possible o igin could be
ela ed o small agg ega ions o LaF
3
NPs.
These esul s con i m ha 1.2Nd
3+
doped-80SiO
2
-20LaF
3
coa ings
Fig. 6. (a) and (b) HR TEM images o he sc aped 1.2Nd
3+
doped- 80SiO
2
-20LaF
3
hea ea ed a 180◦C o 3 h and 450◦C o 1h and (c) XRD pa e n o he 1.2Nd
3+
doped- 80SiO
2
-20LaF
3
coa ing hea ea ed a 180◦C o 3 h and 450◦C o 1h.
Fig. 7. (a) Room empe a u e emission spec um o he
4
F
3/2
→
4
I
11/2
ansi ion o 1.2Nd
3+
doped- 80SiO
2
-20LaF
3
coa ing ob ained by exci ing a 786 nm. (b) Room
empe a u e exci a ion spec um ob ained by collec ing he luminescence a 1063 nm.
Fig. 8. Semi-loga i hmic plo o he expe imen al decay o he 1.2Nd
3+
doped-
80SiO
2
-20LaF
3
coa ing hea ea ed 3h a 180◦C and 1h a 450◦C ob ained
unde 786 nm exci a ion by collec ing he luminescence a 1063 nm (black line)
and 1.2Nd
3+
doped LaF
3
NPs ( ed line).
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
8
p ese e he luminescence p ope ies o Nd
3+
in LaF
3
NCs being a
p omising ou e o p epa e glass-ce amic coa ings wi h ele an pho-
onic applica ions.
4. Conclusions
The syn hesis o he LaF
3
NPs aqueous suspensions was op imized,
selec ing a eac ion ime o 2h as he mos app op ia ed o achie e he
bes p ope ies o size, shape, and c ys allized ac ion. An exhaus i e
physicochemical cha ac e iza ion allows us o conclude ha he c ys al
size and he shape o he NPs, as well as he amoun o dopan , a e key
pa ame e s o ake in o accoun o achie ing good mechanical and
spec oscopic pe o mances. Fu he mo e, i was ound ha 1.2 mol.%
Nd
3+
is he highes possible amoun o Nd
3+
dopan in LaF
3
NPs be o e
concen a ion quenching occu s.
T anspa en OxGCs coa ings wi h composi ion 1.2Nd
3+
doped-
80SiO
2
-20LaF
3
we e ob ained o he i s ime by he “P e-c ys allized
NPs ou e” om he inco po a ion o he NPs suspension in o silica sol
p ecu so s. Nd
3+
-LaF
3
NPs a e s able in he silica sol as well as in he
coa ings, main aining hei composi ion, mo phology, and op ical
p ope ies. The luminescence emission o he 1.2 Nd
3+
-80SiO
2
-20LaF
3
coa ings con i ms he e iciency o he inco po a ion o he Nd
3+
in o he
c ys als and he s abili y o he LaF
3
along he p esen sol-gel ou e. The
exci ed-s a e li e ime alue was ound o be 440 µs.
Al hough, he e is enough oom o u he imp o e he syn hesis
p ocess by adjus ing he a e ea h concen a ion, he p esen esul s
con i m ha his p ocessing ou e appea s as p omising and sui able o
p epa ing Ln: Oxy luo ide sol-gel coa ings wi h high luminescence
e iciency.
Disclosu es
All au ho s decla e ha hey ha e no con lic s o in e es .
Con i ma ion o au ho ship
We, he unde signed, con i m ha we a e he join au ho s o he
abo e pape . We con i m ha all he au ho s ha e had ma e ial inpu
in o he submission.
We con i m ha , o ou knowledge, all he claims, s a emen s and
conclusions a e ue and a e ou join ly held opinions.
We con i m ha we all accep he e ms o publica ion o he
publishe .
Decla a ion o Compe ing In e es
The au ho s decla e he ollowing inancial in e es s/pe sonal e-
la ionships which may be conside ed as po en ial compe ing in e es s:
Ma ia Eugenia C uz epo s inancial suppo was om MICINN unde
p ojec s PID2020-115419GB-C21- C22/AEI / 10.13039/
501100011033.
Da a a ailabili y
No da a was used o he esea ch desc ibed in he a icle.
Acknowledgemen s
The au ho s acknowledge inancial suppo om MICINN unde
p ojec s PID2020-115419GB-C21- C22/AEI / 10.13039/501100011033
and om he Basque Coun y Uni e si y unde p ojec GIU21/006. This
a icle is a pa o dissemina ion ac i i ies o he p ojec FunGlass, which
has ecei ed unding om he Eu opean Union´s Ho izon 2020 esea ch
and inno a ion p og am unde g an ag eemen No 739566.
Re e ences
[1] R.K. Sha ma, P. Ghosh, Lan hanide-doped luminescen nanophospho s ia ionic
liquids, F on . Chem. 9 (2021) 1–26.
[2] H. Guo, F. Li, J. Li, H. Zhang, Luminescen p ope ies o Eu-doped anspa en
glass-ce amics con aining YPO
4
nanoc ys als, J. Am. Ce am. Soc. 94 (6) (2011)
1651–1653.
[3] Y. Chen, G.H. Chen, X.Y. Liu, T. Yang, Enhanced up-con e sion luminescence and
op ical he mome y cha ac e is ics o E
3+
/Yb
3+
co-doped anspa en phospha e
glass-ce amics, J. Lumin. 195 (2018) 314–320.
[4] S. Be neschi, S. So ia, G.C. Righini, G. Alombe -Goge , A. Chiappini, A Chiase a, e
al., Ra e-ea h-ac i a ed glass-ce amic wa eguides, Op . Ma e 32 (12) (2010)
1644–1647.
[5] Y. Teng, K. Sha a udeen, S. Zhou, J. Qiu, Glass-ce amics o pho onic de ices,
J. Ce am. Soc. Japan 120 (1407) (2012) 458–466.
[6] M. Fe a i, G.C. Righini, Glass-ce amic ma e ials o guided-wa e op ics, In . J.
Appl. Glas. Sci. 6 (3) (2015) 240–248.
[7] A. Acha ya, K. Bha acha ya, C. Kuma Ghosh, A. Na ayan Biswas, S. Bha acha ya,
Cha ge ca ie anspo and elec ochemical s abili y o Li
2
O doped glassy
ce amics, Ma e . Sci. Eng. B 260 (2020) 1–7.
[8] A. Sengup a, P. Halde , M.S. Ali, C.K. Ghosh, S. Bha acha ya, Li
2
O-ZnO-MoO
3
-
SeO
2
glass-nanocomposi es and hei c ys alline coun e pa s: Mic os uc u e,
elec ical anspo mechanism and i s p inciple DFT analysis, Phys. Sc . 97 (8)
(2022) 1–13.
[9] G. Go ni, J.J. Vel´
azquez, J. Mosa, R. Balda, J. Fe n´
andez, A. Du ´
an, e al.,
T anspa en glass-ce amics p oduced by Sol-Gel: A sui able al e na i e o pho onic
ma e ials, Ma e ials 11 (2) (2018) 1–30.
[10] P.P. Fedo o , A.A. Luginina, A.I. Popo , T anspa en oxy luo ide glass ce amics,
J. Fluo . Chem. 172 (2015) 22–50.
[11] G. Alombe -Goge , C. A mellini, S. Be neschi, A. Chiappini, A. Chiase a, M Fe a i,
e al., Tb
3+
/Yb
3+
co-ac i a ed Silica-Ha nia glass ce amic wa eguides, Op . Ma e .
33 (2) (2010) 227–230.
[12] K. Biswas, A.D. Son akke, J. Ghosh, K. Annapu na, Enhanced blue emission om
anspa en oxy luo ide glass-ce amics con aining P
3+
:BaF
2
nanoc ys als, J. Am.
Ce am. Soc. 93 (4) (2010) 1010–1017.
[13] Y. Wang, J. Ohwaki, New anspa en i oce amics codoped wi h E
3+
and Yb
3+
o e icien equency upcon e sion, Appl. Phys. Le . 63 (1993) 3268–3270.
[14] Y. Wei, J. Li, J. Yang, X. Chi, H. Guo, Enhanced g een upcon e sion in Tb
3+
–Yb
3+
co-doped oxy luo ide glass ce amics con aining LaF
3
nanoc ys als, J. Lumin. 137
(2013) 70–72.
[15] A. Sa ako skis, G. K ieke, Upcon e sion luminescence in e bium doped anspa en
oxy luo ide glass ce amics con aining hexagonal NaYF
4
nanoc ys als, J. Eu .
Ce am. Soc. 35 (13) (2015) 3665–3671.
[16] A. He mann, M. Tylkowski, C. Bocke , C. Rüssel, Cubic and hexagonal NaGdF
4
c ys als p ecipi a ed om an aluminosilica e glass: P epa a ion and luminescence
p ope ies, Chem. Ma e . 25 (14) (2013) 2878–2884.
[17] J. Cao, W. Chen, D. Xu, F. Hu, L.P. Chen, H. Guo, Wide- ange he mome y based
on g een up-con e sion o Yb
3+
/E
3+
co-doped KLu
2
F
7
anspa en bulk
oxy luo ide glass ce amics, J. Lumin. 194 (2018) 219–224.
[18] C. Koepke, K. Wisniewski, M. ˙
Zelechowe , E. Cze ska, The ole o phonons in he
luminescence cha ac e is ics o SICLOF oxy luo ide glass and glass-ce amic ibe s
doped wi h E
3+
/Yb
3+
, J. Lumin. 204 (2018) 278–283.
[19] R. Lisiecki, E. Augus yn, W. Ryba-Romanowski, M. Zelechowe , E -doped and E ,
Yb co-doped oxy luo ide glasses and glass-ce amics, s uc u al and op ical
p ope ies, Op . Ma e . 33 (11) (2011) 1630–1637.
[20] E.L. Ca es, M. Cho, J.H Kim, Con e ing isible ligh in o UVC: Mic obial
inac i a ion by P
3+
-ac i a ed upcon e sion ma e ials, En i on. Sci. Technol. 45
(8) (2011) 3680–3686.
[21] R.A. Youness, M.A Taha, M Ib ahim, A. El-Kheshen, FTIR Spec al cha ac e iza ion,
mechanical p ope ies and an imic obial p ope ies o La-doped phospha e-based
bioac i e glasses, Silicon 10 (3) (2018) 1151–1159.
[22] M.E. C uz, Y. Cas o, A. Du ´
an, Glasses and glass-ce amics p epa ed by sol–gel,
Re . Modul. Ma e . Sci. Ma e . Eng. 2 (2020) 1–14.
[23] D. Chen, Y. Wang, Y. Yu, E. Ma, L. Zhou, Mic os uc u e and luminescence o
anspa en glass ce amic con aining E
3+
:BaF
2
nano-c ys als, J. Solid S a e Chem.
179 (2) (2006) 532–537.
[24] J.J. Vel´
azquez, J. Mosa, G. Go ni, R. Balda, J. Fe n´
andez, L. Pascual, e al.,
T anspa en SiO
2
-GdF
3
sol–gel nano-glass ce amics o op ical applica ions, J. Sol-
Gel Sci. Technol. 89 (1) (2019) 322–332.
[25] M. Jalilpou , M. Rez ani, M.T. Hamedani, K. Fa hadi, In es iga ion o he
s uc u al p ope ies and bioac i i y o P
2
O
5
–CaO–Na
2
O–TiO
2
glass and glass-
ce amics syn hesized ia a no el sol–gel me hod by ace one and DMF sol en s,
J. Sol-Gel Sci. Technol. 97 (1) (2021) 213–227.
[26] S Fujiha a, C Mochizuki, T. Kimu a, Fo ma ion o LaF
3
mic oc ys als in sol-gel
silica, J. Non C ys . Solids. 244 (2) (1999) 267–274.
[27] N Pawlik, B Szpikowska-S oka, T Go yczka, WA. Pisa ski, Sol-gel glass-ce amic
ma e ials con aining CaF
2
: Eu
3+
luo ide nanoc ys als o eddish-o ange
pho oluminescence applica ions, Appl. Sci. 9 (24) (2019) 1–11.
[28] M. Secu, C.E. Secu, C. Ghica, Eu
3+
-doped CaF
2
nanoc ys als in sol-gel de i ed glass-
ce amics, Op . Ma e . 33 (4) (2011) 613–617.
[29] G. Go ni, M.J. Pascual, A. Caballe o, J.J. Vel´
azquez, J. Mosa, Y. Cas o, e al.,
C ys alliza ion mechanism in sol-gel oxy luo ide glass-ce amics, J. Non C ys .
Solids. 501 (2018) 145–152.
[30] G. Go ni, J.J. Vel´
azquez, J. Mosa, G.C. Ma he , A. Se ano, M. Vila, e al.,
T anspa en sol-gel oxy luo ide glass-ce amics wi h high c ys alline ac ion and
s udy o e inco po a ion, Nanoma e ials 9 (4) (2019) 1–16.
M.E. C uz e al.
Jou nal o Non-C ys alline Solids 601 (2023) 122050
9
[31] M.E. C uz, J. Li, G. Go ni, A. Du ´
an, G.C. Ma he , R. Balda, e al., Nd
3+
doped SiO
2
-
KLaF
4
oxy luo ide glass-ce amics p epa ed by sol-gel, J. Lumin. 235 (118035)
(2021) 1–7.
[32] M.E. C uz, J. Li, G. Go ni, A. Du ´
an, G.C. Ma he , R. Balda, e al., C ys alliza ion
p ocess and si e-selec i e exci a ion o Nd
3+
, C ys als 11 (464) (2021) 1–11.
[33] J.J. Vel´
azquez, R. Balda, J. Fe n´
andez, G. Go ni, M. Sedano, A. Du ´
an, e al.,
S uc u al and op ical p ope ies in Tm
3+
/Tm
3+
–Yb
3+
doped NaLuF
4
glass-
ce amics, In . J. Appl. Glass. Sci. 12 (4) (2021) 485–496.
[34] E.M. Rod igues, E.R. Souza, J.H. Mon ei o, R.D.L. Gaspa , I.O. Mazali, FA. Sigoli,
Non-s abilized eu opium-doped lan hanum oxy luo ide and luo ide nanopa icles
well dispe sed in hin silica ilms, J. Ma e . Chem. 22 (45) (2012) 24109–24123.
[35] M.E. C uz, Y. Cas o, A. Du ´
an, T anspa en oxy luo ide glass-ce amics ob ained by
di e en sol-gel ou es, J Sol-Gel Sci. Technol. 102 (2022) 523–533.
[36] M.E. C uz, A. Du ´
an, R. Balda, J. Fe n´
andez, G.C. Ma he , Y. Cas o, A new sol–gel
ou e owa ds Nd
3+
-doped SiO
2
–LaF
3
glass-ce amics o pho onic applica ions,
Ma e . Ad . 1 (9) (2020) 3589–3596.
[37] K Gipson, C Kuce a, D S ad he , K S e ens, J Balla o, P. B own, The in luence o
syn hesis pa ame e s on pa icle size and pho oluminescence cha ac e is ics o
ligand capped Tb
3+
:LaF
3
, Polyme s 3 (2011) 2039–2052.
[38] JW S ouwdam, FCJM. Van Veggel, Imp o emen in he luminescence p ope ies
and p ocessabili y o LaF
3
/Ln and LaPO
4
/Ln nanopa icles by su ace modi ica ion,
Langmui 20 (26) (2004) 11763–11771.
[39] A.M. C oss, P.S. May, F.C.J.M. Van Veggel, M.T. Be y, Dipicolina e sensi iza ion o
eu opium luminescence in dispe sible 5%Eu:LaF
3
nanopa icles, J. Phys. Chem. C
114 (35) (2010) 14740–14747.
[40] A Sa ka , A Bhowmik, S. Suwas, Mic os uc u al cha ac e iza ion o ul a ine-g ain
in e s i ial- ee s eel by X- ay di ac ion line p o ile analysis, Appl. Phys. A 94 (4)
(2009) 943–948.
[41] A. Chamuah, S. Ojha, K. Bha acha ya, C.K. Ghosh, S. Bha acha ya, AC
conduc i i y and elec ical elaxa ion o a p omising Ag
2
S-Ge-Te-Se chalcogenide
glassy sys em, J. Phys. Chem. Solids. 166 (2022), 110695.
[42] A Vane se , K Kald ee, L Puus , K Kee end, A Ne edo a, S Fedo enko, e al.,
Rela ion o c ys allini y and luo escen p ope ies o LaF
3
:Nd
3+
nanopa icles
syn hesized wi h di e en wa e -based echniques, Chemis ySelec 2 (17) (2017)
4874–4881.
[43] Y.T. P abhu, K.V. Rao, V.S.S. Kuma , B.S. Kuma i, X- ay analysis by Williamson-
Hall and size-s ain plo me hods o ZnO nanopa icles wi h uel a ia ion, Wo ld J.
Nano Sci. Eng. 04 (01) (2014) 21–28.
[44] Y.Y. Kim, A.S. Schenk, J. Ihli, A.N. Kulak, N.B.J. He he ing on, C.C. Tang, e al.,
A c i ical analysis o calcium ca bona e mesoc ys als, Na . Commun. 5 (2014).
[45] C. Liu, D. Chen, Con olled syn hesis o hexagon shaped lan hanide-doped LaF
3
nanopla es wi h mul icolo upcon e sion luo escence, J. Ma e . Chem. 17 (37)
(2007) 3875–3880.
[46] G. Go ni, J.J. Vel´
azquez, G.C. Ma he , A. Du ´
an, G. Chen, M. Sunda a ajan, e al.,
Selec i e exci a ion in anspa en oxy luo ide glass-ce amics doped wi h Nd
3+
,
J. Eu . Ce am. Soc. 37 (4) (2017) 1695–1706.
[47] J. Azka go a, L. Ma ciniak, I. Ipa agui e, R. Balda, W. S ek, M. Ba edo-
Zu ia ain, e al., In luence o g ain size and Nd
3+
concen a ion on he s imula ed
emission o LiLa
1-x
NdxP
4
O
12
c ys al powde s, Op . Ma e . 63 (2017) 46–50.
[48] R. Balda, J. Fe nandez, A. Mendio oz, J.L. Adam, B. Boula d, Tempe a u e-
dependen concen a ion quenching o Nd
3+
luo escence in luo ide glasses,
J. Phys.: Condens. Ma e 6 (1994) 913–924.
[49] I.A. Sa o, M. We heid, C. Dosche, M. Oezaslan, The ole o poly inylpy olidone
(PVP) as a capping and s uc u e-di ec ing agen in he o ma ion o P nanocubes,
Nanoscale Ad 1 (8) (2019) 3095–3106.
[50] J.Q. Hong, L.H. Zhang, P.X. Zhang, Y.Q. Wang, Y. Hang, G ow h, op ical
cha ac e iza ion and e alua ion o lase p ope ies o Nd:LaF
3
c ys al, J. Alloys
Compd. 646 (2015) 706–709.
M.E. C uz e al.
