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SPECTROSCOPIE OF LASER DYE OXAZINE-170 AS A FUNCTION OF ENVIRONMENT AND pH
M. Eyal, R. Gvishi, R. Reisfeld
To cite this version:
M. Eyal, R. Gvishi, R. Reisfeld. SPECTROSCOPIE OF LASER DYE OXAZINE-170 AS A FUNC-
TION OF ENVIRONMENT AND pH. Journal de Physique Colloques, 1987, 48 (C7), pp.C7-471-C7-
473. �10.1051/jphyscol:19877112�. �jpa-00226929�
JOURNAL D E PHYSIQUE
C o l l o q u e C7, s u p p l k m e n t au n012, Tome 48, dgcembre 1 9 8 7
SPECTROSCOPIE OF LASER DYE OXAZINE-170 AS A FUNCTION OF ENVIRONMENT AND pH
M. EYAL, R. GVISHI and R. REISFELD(')
D e p a r t m e n t of I n o r g a n i c and A n a l y t i c a l C h e m i s t r y , Hebrew U n i v e r s i t y ,
IL-91904J e r u s a l e m , I s r a e l
A b s t r a c t : A b s o r p t i o t l and e m i s s i o n s p e c t r a o f Oxnr.i.r~e
-
1.70, whi.cli is one of i m p o r t a n t l a s e r d y e s i n t h e r e g i o n o f 600-700 nm were s t u d i e d a s a f u n c t i o n of e n v i r o n m e n t i n w a t e r . e t h a n o l , methnnol, t e t r a h y d r o f u r a n , c h l o r o f o r m , i n t h i n f i l m s o f p o l y m e t h y l m e t h a c r y l a t e (PMMA) and s o l - g e l t h i n f i l m s , nnd i n b u l k s o l - g e l g l a s s . The a b s o r p t i o n s p e c t r a a r e pll s e n s i t i v e and t h e pII dependence r e v e ~ l s e x i s t e n c e o f two d i s t i n c t s p e c i e s o f o x n z i t l e , a c a t i o n i c forln nnd R m o l e c u l a r fo!-m, e x t i n c t i o n c o e f f i c i e n t o f t h e l a t t e r b e i n g a b o u t h a l f o f t h e former. The quantum y i e l d o f t h e c a t i o n i c form i s h i g h w h i l e t h e quantunl y i e l d o f t h e m o l e c u l a r form i s a n o r d e r o f magnitude l o w e r . Formation o f d i m e r s a t h i g h c o n c e n t r a t i o n s o f o x a z i n e p o s e s a s e r i o u s problem i n t h i n f i l m s , which may b e remedied by d e c r e a s i n g t h e c o n c e n t r a t i o n o f t h e d y e arid by m u l t i p l e t h i n f i l m c o n t i r l g n . I'lle b u l k g l a s s e s show quantum e f f i c i e n c y d e p e n d e n t on c o r i d t i o n s o f preparatS.on.
T h e s e r e s u l t s form a f r a m e of g u i d e l i n e s f o r a c h o i c e o f o p t i m a l e n v i r o n m e n t o f a l a s e r d y e , whether i n s o l . u t i o n s o r i n a s o l i d m a t r l x .E x p e r i m e n t a l
The p r o c e d u r e s f o r p r e p a r a t i o n o f s o l u t i o n s , t h i n f i l m s o f p o l y m o t h y l m e t i ~ a c r y l a t e (PMMA), t h i n f i l m s o f s o l - g e l g l a s s e s and t h e b u l k s o l - g e l g l a s s e s c a n b e found i n r e f s [ 1 , 2 ] . The a b s o r p t i o n s p e c t r a o f the s a m p l e s were' measured o n a Lambda
5
Perkin-Elmer s p e c t r o p h o t o m e t e r and t h e e m i s s i o n s p e c t r a were alensured o n a SLM s p e c t r o f l u o r i m e t e r and c o r r e c t e d f o r s p e c t r a l r e s p o n s e o f t h e i n s t r u m e n t . Tile quantum y i e l d s o f t h i n f i l m s ' d o p e d by o x a z i n e were measured by n c a l i b r a t e d p h o t o v o l t a i c c e l l and conlpared w i t h t h e known[3]
quantum y i e l d o f Rhodatsine 6G (Rh 6G) i n t h i n ,PMMA f i l m . The quantum y i e l d s o f b u l k s a m p l e s were d e t e r m i n e d b y comparison o f t h e e m i s s i o n s p e c t r a w i t h t h e e m i s s i o n s p e c t r u m o f Rh6G i n PMMA m a t r i x h a v i n g known quantum y i e l dC3.41.
R e s u l t s and d i s c u s s i o n ocn
F i g . 1 p r e s e n t s t h e dependence o f t h e e m i s s i o n Oo,
s p e c t r u m , o f o x a z i n e o n t h e c o n c e n t r a t i o n o f a c i d o r b a s e . From t o p t o bottom: i n m e t h a n o l , e t h a n o l , t e t r a h y d r o f u r a n and c h l o r o f o r m . The plI numbers a r e g i v e n a s p s e u d o v a l u e s s i n c e o u r s o l u t i o n s a r e n o t c o m p l e t e l y a q u e o u s . F o r a l l t h e s o l v e n t s w e o b s e r v e t h g c h a r a c t e r i s t i c r e d s h i f t which o c c u r s a t a b o u t OJn ( n o m i n a l ) pH '10 h a v i n g maxinlum a b s o r p t i o n a t 620-625 nm and maximum e m i , s s i o n a t 650-660 nm. Above plI-10 t h e d n t t ~ i n a n t form o f o x a z i n e a b s o r b s a t a b o u t 500 nnl and
elnjl:s a t a b o u t 590 nm. T h e s e o b s e r v a t i o n s may b e WfiVECCNGTII (nm)
e x p l a i n e d b y t h e e q u i l i b r i u m :
F i g . l : A h a o r p t i o n s p e c t r a o f 10 -6 rlc,o M/L o x a s i n e : a - m e t h a n o l , b - e t h a -
n o l , c- '1'IIF. d - c h l o r o f o r m . The numbers r e f e r t o c o n c e n t r a t i o n s h ~ b r 2 500 R~
o f lIC1 c o r r e s p o n d i n g t o pH=:l-1, 2-7,3-10,
4- 13.
(''~nrique Berman. Professor of Solar Energy
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19877112
C7-472 JOURNAL DE PHYSIQUE
Wovelengttl [ nrn ]
where a t t h e i n t e r m e d i a t e c o n c e n t r a t i o n s o f [II'] b o t h for,rns a p p e a r . ?.Inere e x i s t s a t h i r d form o f o x a z i n e which a b s o r b s a t 1170-1190 nm ond e m i t s a t hbout 580 nm nnd i s s t a b l e o n l y i n v e r y a c i d i c e n v i r o n m e n t , pH < = 0 ; howevcr t h i s form shows an energy t r f l n s f e r t o a t r i p l e t s t a t e and t h u s is n o t nppl-Lr.,al~le n s R l n s e r dye. F i g . % p r e s e n t s t h e a b s o r p t i o n ( u p p e r ) end t h e e m i s s i o n ( l o w o r ) s p e c t r a o f Oxnzin i n t h i n FMMA f i l m . Absorptj.on and e m i s s i o n s p e c t r a o f R h 6 ~ ontl n BAST: dye
U339
a r e g i v e n f o r c o m p a r i s o n . Both a b s o r p t i o r i and e m i s s i o n s p e c t r a o f tlie d y e s a r e s l i g h t l y red- s h i f t e d , t h e phenomena common i n PMMA m a t r i x . The quantum y i e l d o f t h e o x a z i n e i s100.
4 500 600 ' 700 Wavelength [nrn J
0.10
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Fig.2: A b s o r p t i o n ( u p p e r , c u r v e 1 ) and Fig.3: a - A b s o r p t i o n s p e c t r a o f e m i s s i o n ( l o w e r , c u r v e 1 ) s p e c t r a o f o x a z i n e i n b u l k g l a s s a t c o n s t a n t o x a z i n e i n t h i n fi1.m o f PMMA. A b s o r p t i o n p f ~ = 0 . 4 and a s n f u n c t i o n o f conc- nnd e m i s s i o n s p e c t r a o f nh6G ( c u r v e 2 , e n t r a t i o n and t i m e e l a p g e d a f t e r t h e
~ n d a BASF dye # 339 ( c u r v e 3 ) a r e g i v e r 1 p r e p a r a t i o n ; 1-4.4'10 M/L a f t e r
f o r comparison. f o u r ? y s , 2 - a f t e r f i v e d a y s 3-
4 .1lff10- MIL a f t e r f i v e d a y s . b-Comparison o f a b s o r p t i o n s p e c t r a 2 7 i 5 3 , which i s l o w e r t h a n i n c h l o r o f o r n l o f o x a z i n e j.n t11i.n f i l m s and b u l k ( 6 0 % ) from which t h e t h i n f i l m w a s g l a s s ; 1.2.3: T h i n f i l m s p r e p g r e d p r e p a r e d . T h i s i s p r o b a b l y d u e t o from f@e c o n r e t r a t - i o n s 5*10
,
d i m e r i z a t i o n , s i n c e t h e c o n c e n t r a t i o n of 8.8*10 and 1'; MM/L r e s p e c t i v e l y . o x a z i n e i n t h e t h i n f i l m i s a b o u t
4-
bulk-gprepared from t h e s o l u t i o n times h i g h e r t h a n i n t h e P r e c u r s o r o f 2'10 M/I,. C- Etnl.ssion s p e c t r u m s o l u t i o n , due t o s h r i n k a g e o f t h e f i l m o f l o w - a c i d b u l k g l e s s doped w i t h i n r e s p e c t t o t h e p r e c u r s o r s o l u t i o n . o x a z i n e . E x c i t e d a t 625 nm.F i g . 3 , m i d d l e p i c t u r e , i n which t h e E x c i t e d a t 625 nm.
a b s o r p t i o n s p e c t r a o f o x a z i n e i n t h i n s o l - g e l g l ~ s s f i l m s n t v a r i o u s s t a r t i n g c o n c e n t r a t i o n s ( c u r v e s 1 . 2 . 3 ) a r e
compared w i t h t h e a b s o r p t i o n s p e c t r u m o f o x a z i n e i n b u l k s o l - g e l sample ( c u r v e 4 ) d e m o n s t r a t e s c l e a r l y t h i s t h e s i s . I t is o b s e r v e d t l i a t t h e amount o f d i m e r s a b s o r b i n g a t 5 8 0 nm i s much h i g h e r i n t h i n s o l - g e l f i l m t h a n i n t h e b u l k g l a s s ,
~ ~ i i i l e t h e quantum y i e l d o f o x a z i n e i n s o l - g e l fi.1.m i.9 -5% RS compared w i t h 45i5% i n ttle b u l k g l a s s . The volunle o f s o l . - g e l t h i n f i l m may be n s low ns 1-'2% o f t h e volr~me o f t h e p r e c u r s o r s o l u t i o n , h e n c e t h e c o t ~ c e n t r n t i o n o f oxnzi.ne may i n c r e a s e up t o
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Summary
'I'he o x a z i n e doped s o l - g e l g l a s s shows good p r o s p e c t s f o r b e i n g a s u i t a b l e m a t e r i a l f o r a s o l i d - s t a t e t u n a b l e dye l a s e r . The c o n d i t i o n s o f p r e p a r a t i o n o f s u c h a m a t e r i a l a r e c r u c i a l i n r e s p e c t t o t h e quantum y i e l d and tlie s t a b i l i t y o f t h e d o p a n t . The t h i n f i l m o f o x a z i n e seems l e s s f e a s i b l e due t o f o r m a t i o n o f d i m e r s and low quantunl y i e l d , however t h i s may b e remedied by uui11g u v e r y low c o n c e n t r a t i o n o f o x a z i n e i n t h e p r e c u r s o r s o l u t i o n and s u c c e s s i v e t h i n f i l m c o a t i n g s from t h i s s o l u t i o n .
two o r d e r s o f nlagni t u d e i n r e s p e c t t o t h e s t a r t i n g c o n c e n t r a t i o n . The c o n t r a c t i o n o f b u l k s o l - g e l g l n s s i s a b o u t t e n t i m e s s m a l l e r t h a n t h a t o f t h e t h i n f i l m .
The l o w e r p i c t l r r e o f F i g . 3 d e m o r ~ s t r a t e s t h e e f f e c t o f c o n c e n t r n t i o n o f a c i d on t h e a b s o r p t i o n s p e c t r a o f oxazi.ne. A t t h e h i g h c o n c e n t r a t i a n s o f t h e a c i d t h e b l u e s h i f t o f t h e a b s o r p t i o n s p e c t r a (which i s a b s e n t i n t h e p r e c u r s o r s o l u t i o n ) a p p e a r s a f t e r
3- 4
d a y s o f t h e g e l a t i o n , which i s a l s o a c c e l e r a t e d by t h e higli c o n c e n t r a t i o n o f o x a z i n e . A t low c o n c e n t r a t i o n o f t h e a c i d t h i s p r o c e s s d o e s n o t t a k e p l a c e and t h e a b s o r p t i o n s p e c t ; r a o f o x a z i n e loolts l i k e t h e crll've [I i r ~ t l ~ c m i d d l e p i c t u r e . A t f i r s t o b s e r v a t i o n t h i s b e h a v i o u r is j u s t t h e o p p o s i t e o f t h a t o f o x a z i n e i n s o l u t i o n s , however, a c l o s e r l o o k r e v e a l s t h a t t h e form o b s e r v e d a t h i g h c o n c e n t r a t i o n s o f a c i d i n t h e b u l k g l a s s a b s o r b s a t 470-490 nm and n o t a t 500 nlll ( t h e a b s o r p t i o n peak o f t h e " d e p r o t o n a t e d " form o f o x a z i n e ) and t h e e m i s s i o n s p e c t r u m (INL shown) o f t h i s form p e a k s a t 550-580 nm. T h e s e a r e i n a good 'greement w i t h the 'pectrum r.bl. rr nn.hold ror empin. ~r ~...so; dopd .01-1.i siu..
runcttwo f o x a z i n e i n a c o n c e n t r a t e d s o l u t i o n Or Conc.nlr.Li~n .nd r.v.l.nllts.
R e f e r e n c e s
1. R . R e i s f e l d , M. Eyal and R . G v i s h i , S p e c t r o s c o p i c b e h a v i o u r o f f l u o r e s c e i n and i t s d i ( m e r c u r y a c e t a t e ) a d d u c t i n g l a s s e s , Chem. Phys. L e t t . i n p u b l i c a t i o n . 2 . D . A v n i r , D. I.evy and R . I l e i s f ' e l d , J . Pliys. Chem.
88
(198'1)5956
3.
M.L. L e s i e c k y and J.M. Drolce, Appl. OpLics21
( 1 9 8 2 ) 5574 .
R . R e i s f e l d , C r i t e r i a and p r o s p e c t s o f new l a s e r s b a s e d on f l u o r e s e n t d y e s i n g l a s s e s , t o b e p u b l i s h e d i n t h i s v o l u ~ ~ l e o f J . d e P h y s i q u e .[*I -
T h i s phenolaenor~ h a s been o b s e r v e d r e c e n t l y i n o u r I r r b o r a t o r y a l s o f o r r h o d a s l i t ~ e 60 i n a c i d i c s o l u t i o n , a c i d i c b u l k g l a s s and i n b o r i c a c i d ~ l t a t r i x , e x h i b i t i n g lol>g - l i v i n g l u m i n e s c e n c e i n t h e g r e e n . The g r e e n and y e l l o w e m i t t i n g s p e c i e s become" o r d i n a r y " rfiodamine and o x a z i n e u n d e r a s l i g h t d i l u t i o l i o f t h e a c i d i c s o l ~ l t i o n .
mn.hold p a r l h ~ l r m ~ ]
-
lop0 115
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710 7 0 lw IWO 1150 454 110 llw%
- 1340
154
of sulphuric acid ' As
mentioned e a r l i e r , t h i s form i s v e r y i n t e r e s t i n g b e c a u s e o f i t s enhanced s i n g l e t - t r i p l e t e n e r g y t r a n s f e r r a t e , however, i t i s n o t s u i t a b l e a s a l a s e r d y e
[*I.
The u p p e r p i c t u r e sllows tlie e m i s s i o n s p e c t r a o f a s t a b l e , c a t i o n i c form o f o x a z i n e i n low- a c i d b u l k s o l - g e l g l a s s .T a b l e I p r e s e n t s t h e t h r e s h 0 1 d powers needed t o s u s t a i n l a s e r s a c t l o n i n t h e o x a z i n e doped s o l - g e l g l a s s .
The f o r m u l a e u s e d may b e found i n r e f [ 4 ] . F o r t h e s a k e o f s i m p l i c i t y t h e s e powers a r e c a l c u l a t e d for pumping a t the'maximum a b s o r p t i o n o f t h e l a s i n g form o f o x a z i n e which i s a t 625 nm. The e m i s s i o n s p e c t r u m o f f i g 3 ( t o p ) was u s e d f o r t h e c a l c u l a t i o n s . I n o r d e r t o e s t i m a t e t h e pulilping power a t t h e wavelength o f 337 na ( n i t r o g e n l a s e r ) , t h e numbers must2 b e m u l t i p l i e d by a s u i t a b l e f a c t o r . F o r a moderate pumping power ( u p t o MW/cm ) we s e e t h a t t h e l a s e r a c t i o n i n t h e s o l - g e l g l a s s
isl
possib- i n t h e r a n g e o f 630- 690 nm and i n t h e r a n g e o f c o n c e n t r a t i o n s from 10 t o 1 0 9 M / L . ~ h i s ~ o m r p o n d r 4 0 tinervecilge power d t ~ e
ordtr fo-'W/cm'.r~onc~ncrat,m [W,1 so-2
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