Op ical Fibe Technology 72 (2022) 102980
A ailable online 18 July 2022
1068-5200/© 2022 The Au ho s. Published by Else ie Inc. This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons.o g/licenses/by-
nc-nd/4.0/).
Tempe a u e e ec s on he emission o polyme op ical ibe s doped wi h
Lumogen dyes
Jon G andes
a
,
*
, Ma ía Asunci´
on Illa amendi
a
, Eneko A ospide
b
, I˜
naki Bikandi
c
,
Ibon A ambu u
a
, Nekane Gua o xena
d
, Olga Ga cía
d
, Joseba Zubia
c
a
Depa men o Applied Physics, Uni e si y o he Basque Coun y (UPV/EHU), Enginee ing School o Bilbao (EIB), Plaza Ingenie o To es Que edo 1, E-48013 Bilbao,
Spain
b
Depa men o Applied Ma hema ics, Uni e si y o he Basque Coun y (UPV/EHU), Enginee ing School o Bilbao (EIB), Spain
c
Depa men o Communica ions Enginee ing, Uni e si y o he Basque Coun y (UPV/EHU), School o Bilbao (EIB), Spain
d
Ins i u o de Ciencia y Tecnología de Políme os, Consejo Supe io de In es igaciones Cien í icas (ICTP-CSIC), Juan de la Cie a 3, E-28006 Mad id, Spain
ARTICLE INFO
Keywo ds:
Polyme op ical ibe
Tempe a u e e ec s
The mal damage
Luminescen ma e ials
Luminescen sola concen a o s
G een ene gy
ABSTRACT
In his pape , we epo he empe a u e e ec s on he luminescence o polyme op ical ibe s doped wi h
Lumogen dyes ( ed and o ange). Speci ically, we ha e analyzed he in ensi y and he a e age wa eleng h o he
spec a emi ed by bo h ibe s when hey a e hea ed om 30 ◦C o 90 ◦C. An almos ull sel – eco e y o he
signal in he ibe doped wi h Lumogen ed has been obse ed when he ibe is subjec ed o he mal cycles wi h
oscilla ing empe a u e a ia ions be ween 30 ◦C and 90 ◦C. The emi ed spec a a e ed/blue shi ed when he
ibe sample is hea ed/cooled wi h a inal empe a u e sensi i i y a ound 0.07 nm/◦C when a s a iona y si ua ion
is eached.
1. In oduc ion
Polyme op ical ibe s (POFs) ha e his o ically occupied a niche in
he op ical ibe wo ld hanks o hei obus ness, la ge co e diame e s,
high nume ical ape u es, and low cos [1]. Pa icula ly, in he las yea s
hey ha e been widely used bo h o sho -haul communica ions links,
whe e dis ances o co e a e gene ally less han 1 km and o a whole
ange o di e en sensing applica ions. When he POFs a e doped wi h
unc ional ma e ials, such as o ganic dyes, ions o a e ea hs, quan um
do s o noble me al nanopa icles, hey can o e a wide ange o ap-
plica ions in he ields o lase s, op ical ampli ie s, illumina o s,
swi ches, senso s o sola concen a o s [2].
Doped polyme op ical ibe s can be ope a ed as luminescen sola
concen a o s (LSCs). The abso bed sunligh h ough hei la e al su -
ace is e-emi ed as luo escence ligh a g ea e wa eleng hs and his is
p opaga ed by o al in e nal e lec ion o he ibe ends, whe e he
pho o ol aic (PV) cells a e placed. The concep o LSCs was in oduced
in he 1970s wi h he objec i e o educing he cos o sola cells [3]. Due
o he impo an de elopmen o new ma e ials and o he u mos u -
gency o sus ainable global de elopmen , esea ch on LSCs has ecen ly
egained momen um. In his p ocess o esea ch, one o he
cha ac e is ics s udied is he geome ic o m o he concen a o , such as
cylind ical LSCs. The s udies abou LSCs o cylind ical shape ha e been
ca ied ou wi h op ical ibe s in mos cases (e.g., doped POFs o
di e en geome ies, mel -spun POFs, o elec ospun nano ibe s) [4–9].
Unlike adi ional plana ec angula LSCs, doped POFs ha e a be e
coupling be ween hei ends and he PV cells and, hey can easily be
connec ed o o he nondoped POFs, o allow spa ial sepa a ion be ween
he ligh collec ion and de ec ion sys ems, i necessa y. All hese p op-
e ies, combined wi h commonly a ailable ma e ials and ease o p o-
cessing, make luo escen ibe sola concen a o s an a ac i e op ion
in he a ea o LSCs [10–12]. Fo example, hey can be employed in ap-
plica ions as building in eg a ed pho o ol aics (BIPVs) in ci ies, o as
powe ul and highly adap i e pho onic pla o ms, such as displays,
chemical eac o s, da k- ield imaging o se e al sensing applica ions
[12].
As LSCs become mo e iable o eal applica ions, i is necessa y o
ge o know p ecisely hei pe o mance unde ealis ic ex e nal condi-
ions. Fo example, he mal damage is p oduced in LSCs due o he high
empe a u es eached unde sola adia ion, in sunny days on he Ea h
o in he Space [13]. I is well known ha he hea de e io a es sub-
s an ially he pe o mance o he sola cells. Speci ically, he e iciency
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (J. G andes).
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Op ical Fibe Technology 72 (2022) 102980
2
o a c ys alline silicon sola cell dec eases 0.5 % o e e y 1 ◦C abo e
25 ◦C [14]. The sola cell empe a u e can each alues well abo e 50 ◦C,
which implies signi ican pe o mance loss o he sola cell. The ope -
a ing empe a u es o he PV cells when hey a e a ached o LSCs a e
coole (up o 10 ◦C) compa ing o he empe a u es o cells acing di ec
sola exposu e [15]. This e ec is due o bo h he a oidance o in a ed
sunligh impinging on he a ached cells and he good spec al ma ching
be ween he emission o LSCs and he esponse o PV cells. Taking in o
accoun all hese conside a ions and ha LSCs a e exposed o di ec
adia ion om he sun, s udies abou he he mal pe o mance o LSCs
can be e y use ul in his applica ion a ea.
The pho oinduced he mal deg ada ion in dye-doped polyme
ma ices mainly b ings abou a chemical p ocess in which he unc ional
bonds o dye molecules a e changed and b oken. As a esul , he dye
molecules may cease o p oduce luo escence o p oduce di e en
luo escence. The pho oinduced deg ada ion o ma e ials om which
LSCs a e made, has been s udied by exposing samples o lase s o UV
adia ion [16–18]. Howe e li le has been in es iga ed abou he mal
e ec s on he p ope ies o LSC de ices [19,20]. The s udy o he em-
pe a u e e ec s on he e iciency o LSCs can help o imp o e he s a-
bili y o hese de ices, o example, i hey a e used in space sola powe
sys ems [13]. An e icien hea dissipa ion can minimize he he mal
deg ada ion o he pe o mance o LSCs and i can become an essen ial
ma e when LSCs a e in high empe a u e en i onmen s. Taking in o
accoun ha he cylind ical geome y o ibe s con ibu es o dissipa e
he hea gene a ed, an in es iga ion o he he mal e ec s in LSCs based
in doped polyme op ical ibe s can p o ide aluable in o ma ion in
o de o de elop s a egic geome ies and disposi ions o LCSs.
In his wo k, we epo he empe a u e dependence o he emission
spec a in he ange 30–90 ◦C o wo di e en luo escen ibe sola
concen a o s. Al hough i is di icul o LSCs o each his empe a u e
on he Ea h su ace, hey can be exposed o highe empe a u es han
90 ◦C i hey a e used in space sa elli es [13]. The luminescen ibe s a e
POFs doped wi h wo di e en ac i e dye de i a i es om pe ylene,
namely Lumogen ed (LR) and Lumogen o ange (LO). Al hough PMMA
has no a good hea esis ance, i is an excellen candida e o be used as
polyme ic ma ix due o i s good chemical s abili y and biocompa i-
bili y, high anspa ency o e a wide spec al ange, high e ac ion
index and easy p ocessabili y. On he o he hand, Lumogen dyes ha e
been ex ensi ely and success ully employed in LSCs, and hey a e s ill
being s udied nowadays [21–23]. We analyze he in luence o empe -
a u e on he emi ed luo escence cha ac e is ics, such as he in ensi y
and he a e age wa eleng h, by subjec ing doped POFs o se e al em-
pe a u e dependen measu emen s, including he mal cycles.
2. Expe imen al
Fig. 1 shows he expe imen al se -up used o s udy he empe a u e
e ec s on he luo escence spec a emi ed om doped ibe s. The ibe s
we e hea ed up by means o a clima e chambe CTS C–70/200 model,
(CTS GmbH, Ge many). The u nace had wo openings ha allowed he
in oduc ion o a ligh sou ce o illumina e he ibe s and all he
necessa y wi ing o de ec ion. In addi ion o he ibe sample o be
analyzed, a he mocouple ( ype-K he mocouple wi h 0.5 ◦C esolu ion)
was in oduced in o he u nace nex o he ibe so ha he empe a u e
o he sample could be accu a ely measu ed. The analyzed sample was
connec ed o a silica mul imode op ical ibe o ansmi he emi ed
ligh up o a ibe -op ic spec ome e (A an es model A aSpec-Mini,
wi h an op ical esolu ion o 1.4 nm o ull wid h a hal maximum)
o he measu emen o he emission spec a. The he mocouple was
connec ed o an USB de ice, which allowed he collec ing o he em-
pe a u e da a. The ligh sou ce used o illumina e he ibe s was a 60 W
incandescen bulb designed o wi hs and empe a u es up o 300 ◦C. The
end o he ibe sample ha is no connec ed o he de ec o was ixed o
a me allic g id placed inside he u nace and i was co e ed so ha he
ligh sou ce illumina es he ibe sample along i s la e al su ace only.
The small ac ion o isible adia ion emi ed om he bulb was enough
o gene a e he luo escence in he ibe s. All he measu emen s we e
no malized by de ec ing he luc ua ions o he ligh sou ce inside he
u nace wi h o he silica mul imode op ical ibe connec ed o o he
ibe -op ic spec ome e .
Be o e pe o ming he measu emen s, we made a calib a ion o he
empe a u e inside he u nace by using he he mocouple. Fig. 2 shows
he empe a u e a ia ion in he u nace when, s a ing om 30 ◦C, an
inc ease o 10 ◦C is applied each 20 min up o 90 ◦C. The ed poin s a e
he empe a u e gi en by he he mocouple placed inside he u nace. I
can be seen ha he hea a e o he u nace is no cons an in all he
empe a u e in e als. I dec eases om an app oxima e a e o 1.2 ◦C/
min a he 30–40 ◦C in e al o 0.8 ◦C/min a he inal s ep, in he
80–90 ◦C one. In all s eps, a e a ansien s a e he empe a u e eaches
a quasi-s able s a e, whe e he empe a u e can be conside ed cons an .
The du a ion o he ime in e als wi h quasi-cons an empe a u e
a ies om a ound 10 min a 40 ◦C o 7 min a 90 ◦C. Sho leng hs o
ibe s (a ound 5 cm) we e used o ensu e he he maliza ion o he
samples a a gi en empe a u e, he uni o mi y o he hea ing and he
non-inclusion o o he luo escence e ec s, such he eabso p ion p o-
cesses and p opaga ion losses. Di e en ypes o empe a u e dependen
measu emen s ha e been pe o med: sho - e m measu emen s whe e
he empe a u e ollows he s ep p o ile shown in Fig. 2 du ing 120 min
Fig. 1. Expe imen al se -up o he measu emen o he empe a u e e ec s on he ibe sample.
J. G andes e al.
Op ical Fibe Technology 72 (2022) 102980
3
and he mal cycles o 420 min be ween 30 ◦C and 90 ◦C. We ha e also
pe o med long- e m measu emen s, keeping he empe a u e cons an
du ing 2 days (a 30 ◦C and 90 ◦C).
The ibe s analyzed in his s udy a e POFs doped wi h he comme -
cially a ailable pe ylene de i a i e dyes, LR and LO. The ibe s we e
ab ica ed by he au ho s using he cas ing me hod o he p e o m
manu ac u ing [24]. The Lumogen se ies o dyes de eloped by BASF
combine high quan um e iciency oge he wi h low pho odeg ada ion
and hey we e speci ically designed o LSCs. The hos polyme is Poly
(me hyl-me hac yla e) (PMMA) in all cases. The highes empe a u e
used (90 ◦C) is jus below he glass ansi ion empe a u e o PMMA. No
de o ma ion o he analyzed ibe samples was de ec ed a e hea ing/
cooling hem. The cha ac e iza ion o he ibe s as sola concen a o s
has been also ca ied ou in [24].
Table 1 summa izes he main cha ac e is ics o he wo ibe s
analyzed. Pho og aphs o bo h doped ibe s, exci ed by he sunligh , a e
shown in Fig. 3. The ibe sample analyzed in each expe imen had no
been p e iously used.
3. Resul s and discussion
In he i s measu emen s we ha e analyzed he luo escence spec a
emi ed by he doped ibe s as he empe a u e is inc eased om 30 ◦C
up o 90 ◦C in s eps o 10 ◦C wi h a o al ime o illumina ion o 2 h (see
Fig. 2). The luo escence spec a o he wo ibe samples ob ained a
h ee empe a u es a e shown in Fig. 4. The inal spec um a a gi en
empe a u e has been calcula ed by a e aging he ob ained spec a o e
he quasi-s able s a e, ha is, o e he in e al whe e he empe a u e is
almos cons an (see Fig. 2). The luo escence spec a co espond o he
adia i e ansi ion S
1
→ S
0
o he dyes embedded in he POFs. F om
Fig. 4, we obse e ha he b oad emission bands o hese Lumogen dyes
a e shi ed o longe wa eleng hs as he empe a u e inc eases and ha
he in ensi y o he bands a 90 ◦C has dec eased in compa ison wi h ha
a 30 ◦C. This e ec can be seen in Fig. 5 whe e he no malized
luo escence in ensi y o each ibe sample as a unc ion o empe a u e
has been displayed. I can be obse ed ha he ou pu in ensi y o bo h
ibe s dec eases almos linea ly along he measu emen ange, wi h a
o al educ ion o a ound 20–25 %. The mos likely mechanisms ha
con ibu e o he dec ease in luo escence in ensi ies as empe a u e
inc eases in bo h dyes a e he non adia i e p ocesses associa ed o
ib a ional elaxa ions o he molecules and o he su ounding ma ix
(PMMA). Al hough LR molecule has a highe olume and molecula
weigh [25], he ob ained esul s indica e ha he ib a ional e-
laxa ions a e no s ongly in luenced by he molecula s uc u al pa e n
o he o ganic dyes. Ano he mechanism esponsible o he dec easing o
he in ensi y wi h empe a u e could be he guide mode leakage a ising
om he dec ease o he e ac i e index o he ibe co e (PMMA) as he
empe a u e is inc eased ( he he mo-op ic coe icien o PMMA is
a ound −1.0×10
−4
/K) [26]. The eason o ha lies in he ac ha he
ou pu in ensi y om he end o he ibe is p opo ional o he numbe
o guided modes p opaga ing h ough he ibe and hese a e p opo -
ional o he squa e o he e ac i e index o he ibe co e [27].
We ha e analyzed he dependence o he cha ac e is ics o he
emi ed spec a on empe a u e by calcula ing hei a e age wa e-
leng hs and oo -mean-squa e ( ms) spec al bandwid hs. Fig. 6 shows
he dependence o he a e age wa eleng hs o he emission spec a on
empe a u e. As can be seen, he e is a ed shi o he a e age wa e-
leng hs as he empe a u e is inc eased, which can be conside ed o be
linea a i s sigh . This empe a u e- ela ed shi may ha e a ange o
o igins, all o hem associa ed o changes ha occu bo h, in he dyes and
in he hos ma ix (PMMA polyme ). These include, among o he s,
he mally ac i a ed changes in he dye o ien a ion in he hos ma ix as
he empe a u e is inc eased o he a ia ion o he PMMA e ac i e
index wi h empe a u e causing shi s in he luo escence peak. By
i ing a linea unc ion o he expe imen al poin s plo ed in Fig. 6, we
ha e es ima ed he e ec o changing he empe a u e on he emission
wa eleng h o ou ibe samples. The slopes o he wo cu es ob ained
om he i ings, which p o ide he empe a u e sensi i i ies, a e dis-
played in Table 2. Rega ding he ms spec al bandwid hs, hey ha dly
a y wi h empe a u e. The ob ained alues ha e been included in
Table 2. Emission wa eleng hs agains empe a u e ha e also been
desc ibed by linea i ings in quan um do s embedded in PMMA [28].
The o igins o hese shi s we e ela ed o he empe a u e dependence o
he bandgap o he quan um do s and o he he mo-op ic e ec o he
PMMA [29].
In o de o analyze he beha io o LSCs unde mo e eal ope a ing
condi ions, we ha e applied he mal cycles o he ibe ha shows be e
pe o mance as LSC, namely he LR-doped ibe [24]. The simula ed
he mal cycles a e shown in Fig. 7. The sample was hea ed up o 90 ◦C
and i was main ained a ha empe a u e du ing 20 min. A e wa ds, i
was cooled down o 30 ◦C and i was main ained a ha empe a u e
du ing o he 20 min. This hea ing and cooling cycle was epea ed suc-
cessi ely ou imes. Fig. 7(a) shows he ime a ia ion o he in ensi y
du ing he hea ing and cooling cycles. I can be obse ed ha when he
sample is hea ed up o 90 ◦C in he i s cycle he in ensi y dec eases
a ound 25 %, in ag eemen wi h he esul s ob ained in he p e ious
expe imen (see Fig. 5). When he empe a u e is lowe ed again o 30 ◦C
he o iginal in ensi y is no o ally eco e ed, a 10 % is los . Howe e ,
he a ia ion o he in ensi y du ing he nex hea ing and cooling cycles
emains qui e s able and a he end only a small dec ease (3–4 %) o he
in ensi y a 30 ◦C and a 90 ◦C is obse ed. This end sugges s ha , a e
Fig. 2. Time e olu ion o he measu ed empe a u e in he u nace in he
30–90
◦C ange. Quasi-s able s a es o empe a u e in he i s s ep ( om 30 ◦C
o 40 ◦C) and in he las one ( om 80 ◦C o 90 ◦C).
Table 1
P ope ies o he analyzed ibe samples. The index o e ac ion o he ibe s is uni o m.
Fibe code Type Dopan Conc. w % Diame e (mm) Exci ed ibe leng h (cm) Non-exci ed ibe leng h (cm) Speci ic hea (PMMA) (J/kg⋅K)
LR-c3 Uncladded Lumogen
F Red 305
0.03 0.98 ±0.05 5.5 ±0.1 3.4 ±0.05 1466
LO-c3 Uncladded Lumogen
F O ange 240
0.03 0.93 ±0.01 5.5 ±0.1 3.4 ±0.05 1466
J. G andes e al.
Op ical Fibe Technology 72 (2022) 102980
4
he i s cycle, when he sample is kep -up o 30 ◦C du ing 20 min, an
almos ull eco e y o he he mal deg ada ion occu s. In simila ex-
pe imen s ca ied ou wi h samples composed o PMMA doped wi h
Rhodamine B and Rhodamine 6G dyes a pa ial eco e y o he he mal
deg ada ion was de ec ed when he samples we e hea ed up o 74 ◦C and
slowly cooled o oom empe a u e. Tha eco e y dec eased du ing he
successi e cycles [19].
The he mal cycles lead also o shi s o he emission spec a (see
Fig. 7(b)). When he sample is hea ed up o 90 ◦C in he i s cycle, he
a e age wa eleng h shows a ed-shi simila o ha ob ained in Fig. 6.
When he sample is cooled down o 30 ◦C, he emission spec a is blue-
shi ed. The ed/blue shi s a e epea ed du ing he subsequen hea ing/
cooling cycles, espec i ely. I he e olu ion o he a e age emission
wa eleng h is analyzed in mo e de ail, we obse e ha when he sample
is cooled down a e he i s hea ing and hea ed again, he a e age
wa eleng hs o he emission a 30 ◦C and 90 ◦C do no e u n o hei
ini ial posi ions; hey a e sligh ly blue-shi ed. The blue-shi is s onge
du ing he i s cycle (app oxima ely 1.3 nm a 30 ◦C and 0.4 nm a
90 ◦C) and smalle du ing he nex cycles o cooling and hea ing (see
Fig. 7(b)).
Wi h he aim o de e mine he o igin o he in ensi y loss and he blue
shi s o he emission du ing he hea ing/cooling cycles, we ha e
analyzed he ime e olu ion o e wo days o he emi ed luo escence
spec a o he same doped ibe a he minimum and a he maximum
Fig. 3. Ou doo pho og aphs o he emission o wo doped ibe s being exci ed by sunligh .
Fig. 4. Fluo escence spec a emi ed om 5.5 cm long ibe samples a h ee di e en empe a u es.
Fig. 5. Ou pu in ensi y o he ibe samples as a unc ion o empe a u e. The illumina ed ibe leng h is 5.5 cm in bo h cases. The solid lines a e he linea i ings o
he da a poin s. The ela i e e o s o da a a e a ound 2 %.
J. G andes e al.
Op ical Fibe Technology 72 (2022) 102980
5
empe a u e o he cycles (i.e., a 30 ◦C and a 90 ◦C, espec i ely). The
ime dependence o he in ensi y and o he a e age wa eleng h o he
emission spec a o a LR sample a bo h empe a u es is shown in Fig. 8.
We ha e plo ed in Fig. 8(a) he ime e olu ion o he in ensi ies a
cons an empe a u e no malized wi h he ini ial alue o he in ensi y
a 30 ◦C. We can no ice ha he ini ial in ensi y alue a 90 ◦C is a ound
20 % lowe han ha ob ained a 30 ◦C, in ag eemen wi h he p e ious
esul s shown in Figs. 5 and 7(a). As we ha e shown, one pa o his
Fig. 6. A e age wa eleng h o he emission bands as a unc ion o empe a u e. The illumina ed ibe leng h is 5.5 cm in bo h cases. The solid lines a e he linea
i ings wi h slopes being 0.051 nm/
◦C and 0.08 nm/◦C o LR and LO, espec i ely.
Table 2
Tempe a u e sensi i i y ob ained om he linea i ings o he expe imen al
poin s o Fig. 6. R
2
is he coe icien o de e mina ion o he linea i ing.
Sample dλ
a
/dT (nm/◦C) R
2
ms spec al bandwid h (nm)
LR-c3 0.051 ±0.001 0.99 32 ±1
LO-c3 0.080 ±0.003 0.99 39 ±3
Fig. 7. (a) Time e olu ion o empe a u e and emission in ensi y in a LR ibe sample unde he ac ion o cyclic hea ing and cooling. (b) Time e olu ion o em-
pe a u e and a e age emission wa eleng h o he LR sample unde he ac ion o cyclic hea ing and cooling. The illumina ed ibe leng h is 5.5 cm.
Fig. 8. Time e olu ion o emission in ensi y (a) and o a e age wa eleng h (b) a wo empe a u es o he LR ibe . The illumina ed ibe leng h is 5.5 cm in bo h
empe a u es.
J. G andes e al.
Op ical Fibe Technology 72 (2022) 102980
6
p e ious empe a u e dependen damage is i e e sible (app ox. a 10
%). In addi ion, om Fig. 8(a) i can be deduced ha a he mally non-
ac i a ed damage is also aking place since he in ensi y a bo h con-
s an empe a u es slowly dec eases app oxima ely a he same a e.
These i e e sible losses could be due o a dec ease o he ac ion o
luo escen dyes, which is ela ed o he blue shi o he emission
wa eleng hs. I is a well-known ac ha he op ical bands shi o lowe
wa eleng hs as he dye dopan concen a ion dec eases. Indeed, we
ha e de ec ed his e ec in POFs doped wi h di e en LR concen a ions
[24]. Fig. 8(b) shows he ime e olu ion o he emission a e age
wa eleng hs a 30 ◦C and 90 ◦C. As can be seen, he blue-shi s a bo h
empe a u es a e simila o hose obse ed in he cycles o Fig. 7(b).
Con a y o he e ec s associa ed o e e sible he mally ac i a ed
p ocesses, he e ec s ela ed o he dec ease o he ac ion o luo escen
dyes, i.e. an in ensi y loss oge he wi h a blue shi o he emission
spec a, show no signs o being e e sible.
Finally, we ha e plo ed in Fig. 9 he emission spec al shi s o he
cycles shown in Fig. 7(b) as a unc ion o empe a u e. The igu e ex-
hibi s mo e clea ly, how he empe a u e e olu ion o he emission
wa eleng hs con e ges o a s able si ua ion a e he i s cycle. The
empe a u e sensi i i y o he ibe sample inc eases sligh ly om 0.059
±0.001 nm/◦C in he i s hea ing o 0.071 ±0.002 nm/◦C in he s able
si ua ion. These alues o he LR ibe sample a e sligh ly di e en om
hose displayed in Table 2 indica ing ha he empe a u e sensi i i y, in
addi ion o i s dependence on dye and on polyme ma ix, i also de-
pends on he hea ing/cooling a e. Simila e ec s o hose obse ed in
ou LR doped ibe ha e been de ec ed in sys ems based on quan um
do s embedded in PMMA [28,29]. In pa icula , a dec ease o he in-
ensi y, oge he wi h a ed–shi o luo escence bands when empe a-
u e inc eases and an inc ease o he in ensi y oge he wi h a blue-shi
o he luo escence spec a when empe a u e dec eases was obse ed
[28]. In [29], upon h ee cycles o hea ing and cooling, a s a iona y
si ua ion wi h a cons an ela ion be ween emission wa eleng h and
empe a u e was eached, as happens o ou LR-doped ibe a e he
i s cycle. The empe a u e sensi i i y alues ob ained in hese sys ems
[29] a e simila o hose ob ained in ou s udy.
4. Conclusions
In his wo k, we ha e p esen ed an expe imen al s udy on he
hea ing up o 90 ◦C o wo polyme op ical ibe s doped wi h dye de-
i a i es om pe ylene, wi h he same concen a ion: Lumogen ed and
Lumogen o ange. We ha e shown ha when he ibe s a e hea ed, o e
2 h, om 30 ◦C o 90 ◦C, he emission bands o he wo ibe s a e linea ly
ed-shi ed and ha he emi ed in ensi y by bo h ibe s dec eases almos
linea ly wi h empe a u e. The o al in ensi y loss in bo h samples is
a ound 20–25 %. By subjec ing he Lumogen ed ibe o hea ing/
cooling cycles, wi h empe a u e oscilla ions om 30 ◦C o 90 ◦C, abou
hal o he in ensi y los in he i s cycle is eco e ed when he sample is
cooled down o 30 ◦C in he ollowing cycles. This dec ease/inc ease o
he luo escence in ensi y du ing cycling could be explained by e e s-
ible he mal ac i a ion/deac i a ion p ocesses associa ed o ib a ions
o he dye molecules and polyme ma ix, and o leakage/inc ease o he
guided modes in he ibe . In addi ion o he in ensi y eco e y, we ha e
obse ed linea ed and blue shi s in he emission spec a as he em-
pe a u e changes. These could be due o he mally ac i a ed changes in
he dye o ien a ion in he hos ma ix o o he a ia ions o he polyme
ma ix’s e ac i e index wi h empe a u e. Along wi h hese e e sible
e ec s, an in ensi y loss oge he wi h a blue shi o he emission spec a
ha e also been obse ed. By measu ing he emission spec a o a sample
o he same doped ibe o e wo days a 30 ◦C and a 90 ◦C, we ha e
shown ha he o igin o hose e ec s could be ela ed o a small dec ease
o he ac ion o luo escen molecule dyes.
The inding o an almos ull sel - eco e y in ou doped polyme
op ical ibe , when i is subjec ed o empe a u e cycles up o 90 ◦C,
ensu es he applicabili y o hese ibe -based luminescen sola
concen a o s in e y high empe a u e en i onmen s on he Ea h
su ace, o e en expand hei applicabili y o Space Sola Powe Sys-
ems. Mo eo e , he empe a u e sensi i i ies p o ided by ou doped
polyme op ical ibe s (a ound 0.07 nm/◦C) could e en add some new
unc ions o hem, such as he sensi i i y o hei su ounding empe -
a u e. In o he wo ds, hese ibe -based luminescen sola concen a o s
could also se e as indica o o isualize and moni o dynamic p ocesses
due o ex e nal s imuli, as empe a u e changes. All hese esul s open
new doo s o he applica ion o hese luminescen ma e ials unde
di e en and ealis ic ex e nal condi ions o sola adia ion.
CRediT au ho ship con ibu ion s a emen
Jon G andes: Resou ces, In es iga ion, Me hodology, Valida ion,
Visualiza ion. Ma ía Asunci´
on Illa amendi: Concep ualiza ion,
Me hodology, Valida ion, W i ing – o iginal d a , Funding acquisi ion.
Eneko A ospide: Resou ces, In es iga ion, Valida ion, Visualiza ion.
I˜
naki Bikandi: Valida ion, Visualiza ion. Ibon A ambu u: Valida ion,
Fo mal analysis, W i ing – o iginal d a . Nekane Gua o xena: Re-
sou ces, W i ing – o iginal d a . Olga Ga cía: Resou ces. Joseba
Zubia: Funding acquisi ion.
Decla a ion o Compe ing In e es
The au ho s decla e ha hey ha e no known compe ing inancial
in e es s o pe sonal ela ionships ha could ha e appea ed o in luence
he wo k epo ed in his pape .
Acknowledgmen s
Minis e io de Ciencia, Inno aci´
on y Uni e sidades (MAT2014-
57429-R, PGC2018-095364-B-I00, PID2021-122505OB-C31, TED2021-
129959B-C21); Gobie no Vasco/Eusko Jau la i za (IT1452-22);
ELKARTEK (KK‑2021/00082, KK‑2021/00092)
Re e ences
[1] Y. Koike, Fundamen als o Plas ic Op ical Fibe s, 1s ed., Wiley-VCH Ve lag GmbH
& Co. KGaA, Weinheim, Ge many, 2015.
Fig. 9. A e age wa eleng hs o he emission spec a o a LR sample as a
unc ion o empe a u e unde he ac ion o cyclic hea ing and cooling. Black
line ep esen s he linea i in he i s hea ing. G een line ep esen s he s able
si ua ion eached a e he i s cycle. The illumina ed ibe leng h is 5.5 cm.
(Fo in e p e a ion o he e e ences o colou in his igu e legend, he eade is
e e ed o he web e sion o his a icle.)
J. G andes e al.
Op ical Fibe Technology 72 (2022) 102980
7
[2] J. A ue, F. Jim´
enez, I. Ayes a, M.A. Illa amendi, J. Zubia, Polyme -Op ical-Fibe
Lase s and Ampli ie s Doped wi h O ganic Dyes, Polym. (Basel) 3 (2011)
1162–1180, h ps://doi.o g/10.3390/polym3031162.
[3] W.H. Webe , J. Lambe, Luminescen g eenhouse collec o o sola adia ion, Appl.
Op . 15 (1976) 2299, h ps://doi.o g/10.1364/AO.15.002299.
[4] K.R. McIn osh, N. Yamada, B.S. Richa ds, Theo e ical compa ison o cylind ical
and squa e-plana luminescen sola concen a o s, Appl. Phys. B Lase s Op . 88
(2007) 285–290, h ps://doi.o g/10.1007/s00340-007-2705-8.
[5] T. Wang, B. Yu, B. Chen, Z. Hu, Y. Luo, G. Zou, Q. Zhang, A heo e ical model o a
cylind ical luminescen sola concen a o wi h a dye-doping coa ing, J. Op . 15
(2013), h ps://doi.o g/10.1088/2040-8978/15/5/055709.
[6] S.F.H. Co eia, P.P. Lima, P.S. And ´
e, M.R.S. Fe ei a, L.A.D. Ca los, High-
e iciency luminescen sola concen a o s o lexible wa eguiding pho o ol aics,
Sol. Ene gy Ma e . Sol. Cells. 138 (2015) 51–57, h ps://doi.o g/10.1016/J.
SOLMAT.2015.02.032.
[7] R.H. Inman, G.V. Shche ba yuk, D. Med edko, A. Gopina han, S. Ghosh,
Cylind ical luminescen sola concen a o s wi h nea -in a ed quan um do s, Op .
Exp ess 19 (2011) 24308, h ps://doi.o g/10.1364/OE.19.024308.
[8] I. Pa ola, D. Za emba, R. E e , J. Kielho n, F. Jakobs, M.A. Illa amendi, J. Zubia,
W. Kowalsky, H.-H. Johannes, High pe o mance luo escen ibe sola
concen a o s employing double-doped polyme op ical ibe s, Sol. Ene gy Ma e .
Sol. Cells 178 (2018) 20–28, h ps://doi.o g/10.1016/J.SOLMAT.2018.01.013.
[9] K. Jakubowski, C.-S. Huang, A. Gooneie, L.F. Boesel, M. Heube ge , R. Hu enus,
Luminescen sola concen a o s based on mel -spun polyme op ical ibe s, Ma e .
Des. 189 (2020) 108518, h ps://doi.o g/10.1016/j.ma des.2020.108518.
[10] Y. Li, X. Zhang, Y. Zhang, R. Dong, C.K. Luscombe, Re iew on he Role o Polyme s
in Luminescen Sola Concen a o s, J. Polym. Sci. Pa A Polym. Chem. 57 (2019)
201–215, h ps://doi.o g/10.1002/pola.29192.
[11] J. Roncali, Luminescen Sola Collec o s: Quo Vadis? Ad . Ene gy Ma e . 10 (2020)
h ps://doi.o g/10.1002/aenm.202001907.
[12] I. Papakons an inou, M. Po noi, M.G. Debije, The Hidden Po en ial o Luminescen
Sola Concen a o s, Ad . Ene gy Ma e . 11 (2020) 2002883, h ps://doi.o g/
10.1002/aenm.202002883.
[13] M.H. Sande s, R.J. Sedwick, The mal Design and Pe o mance o a Luminescen
Sola Concen a o o Space Powe Gene a ion, J. Spacec . Rocke s 56 (2019)
1831–1837, h ps://doi.o g/10.2514/1.A34361.
[14] D. Du, J. Da kwa, G. Kokogiannakis, The mal managemen sys ems o
Pho o ol aics (PV) ins alla ions: A c i ical e iew, Sol. Ene gy 97 (2013) 238–254,
h ps://doi.o g/10.1016/j.solene .2013.08.018.
[15] V.A. Rajkuma , C. Weije s, M.G. Debije, Dis ibu ion o abso bed hea in
luminescen sola concen a o ligh guides and e ec on empe a u es o moun ed
pho o ol aic cells, Renew. Ene gy 80 (2015) 308–315, h ps://doi.o g/10.1016/j.
enene.2015.02.003.
[16] G. G i ini, L. B ambilla, M. Le i, M. Del Zoppo, S. Tu i, Pho o-deg ada ion o a
pe ylene-based o ganic luminescen sola concen a o : Molecula aspec s and
de ice implica ions, Sol. Ene gy Ma e . Sol. Cells 111 (2013) 41–48.
[17] G.D. Peng, Z. Xiong, P.L. Chu, Fluo escence Decay and Reco e y in O ganic Dye-
Doped Polyme Op ical Fibe s, J. Ligh . Technol. 16 (1998) 2365. h p://www.
osapublishing.o g/jl /abs ac .c m?URI=jl -16-12-2365.
[18] B.R. Ande son, M.G. Kuzyk, Imaging s udies o pho odeg ada ion and sel -healing
in an h aquinone de i a i e dye-doped PMMA, Phys. Chem. Chem. Phys. 22
(2020) 28154–28164, h ps://doi.o g/10.1039/D0CP05426G.
[19] F.J. Mesegue , F. Cuss´
o, F. Jaque, C. S´
anchez, Tempe a u e e ec s on he e iciency
o Luminescen Sola Concen a o (LSC) o pho o ol aic sys ems, J. Lumin. 24–25
(1981) 865–868, h ps://doi.o g/10.1016/0022-2313(81)90106-X.
[20] B. Liu, S. Ren, G. Han, H. Zhao, X. Huang, B. Sun, Y. Zhang, The mal e ec on he
e iciency and s abili y o luminescen sola concen a o s based on colloidal
quan um do s, J. Ma e . Chem. C 9 (2021) 5723–5731, h ps://doi.o g/10.1039/
D0TC05466F.
[21] I.A. Ca bone, K.R. F awley, M.K. McCann, Flexible, F on -Facing Luminescen
Sola Concen a o s Fab ica ed om Lumogen F Red 305 and
Polydime hylsiloxane, In . J. Pho oene gy 2019 (2019) 8680931, h ps://doi.o g/
10.1155/2019/8680931.
[22] F.J. Os os, G. Iasilli, M. Ca lo i, A. Pucci, High-Pe o mance Luminescen Sola
Concen a o s Based on Poly(Cyclohexylme hac yla e) (PCHMA) Films, Polym.
(Basel) 12 (2020), h ps://doi.o g/10.3390/polym12122898.
[23] D.M. de Cle cq, S.V. Chan, J. Ha dy, M.B. P ice, N.J.L.K. Da is, Reducing
eabso p ion in luminescen sola concen a o s wi h a sel -assembling polyme
ma ix, J. Lumin. 236 (2021) 118095, h ps://doi.o g/10.1016/j.
jlumin.2021.118095.
[24] E. A ospide, M.A. Illa amendi, I. Ayes a, N. Gua o xena, O. Ga cía, J. Zubia,
G. Du ana, E ec s o Fab ica ion Me hods on he Pe o mance o Luminescen
Sola Concen a o s Based on Doped Polyme Op ical Fibe s, Polym. (Basel) 13
(2021), h ps://doi.o g/10.3390/polym13030424.
[25] I. Pa ola, M.A. Illa amendi, F. Jakobs, J. Kielho n, D. Za emba, H.-H. Johannes,
J. Zubia, Cha ac e iza ion o Double-Doped Polyme Op ical Fibe s as Luminescen
Sola Concen a o s, Polym. (Basel) 11 (2019) 1187, h ps://doi.o g/10.3390/
polym11071187.
[26] Z. Zhang, P. Zhao, P. Lin, F. Sun, The mo-op ic coe icien s o polyme s o op ical
wa eguide applica ions, Polym. (Guild ) 47 (2006) 4893–4896, h ps://doi.o g/
10.1016/j.polyme .2006.05.035.
[27] Allan W. Snyde , John D. Lo e, Op ical Wa eguide Theo y, Sp inge , Bos on, MA,
n.d. 10.1007/978-1-4613-2813-1_29.
[28] Y. Chen, W. Luan, S. Zhang, F. Yang, Quan um-do s based ma e ials o
empe a u e sensing: e ec o cyclic hea ing-cooling on luo escence,
J. Nanopa icle Res. 21 (2019) 185, h ps://doi.o g/10.1007/s11051-019-4629-8.
[29] H.C.Y. Yu, S.G. Leon-Sa al, A. A gy os, G.W. Ba on, Tempe a u e e ec s on
emission o quan um do s embedded in polyme hylme hac yla e, Appl. Op . 49
(2010) 2749–2752, h ps://doi.o g/10.1364/AO.49.002749.
J. G andes e al.
