The local field dependent effect of the critical distance of energy transfer between nanoparticles

Optics Communications 353 (2015) 49-55

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The local field dependent effect of the critical distance of energy iujcrossivfa

transfer between nanoparticles

:hu Viet H aa'b, Do Thi N gaa, Nguyen Ai V iet3, Tran Hong N hung3’*

Institute of Physics, Vietnam Academy o f Science and Technology (VAST), 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi, Viet Nam

Thai Nguyen University of Education, Thai Nguyen, Viet Nam

\RTICLE INFO S T R A c T

article history:

leceived 4 February 2015

:eceived in revised form

April 2015

.ccepted 7 May 2015

available online 8 May 2015

eywords:

orster resonance energy transfer

'ye molecules

luorescent nanoparticles

old nanoparticles

realized plasmon coupled surface energy

ansfer

ritical transfer distance

T he fluorescence re so n an ce en erg y tra n sfe r b e tw e e n v arious ty p e s o f flu o ro p h o re pairs w as in v estig ate

Dye m olecules, q u a n tu m dots, flu o rescen t n an o p artic les (dye m o lecu les e n c a p su la ted in p o ly m e r m

trices) w e re u sed as d o n o r D. Dye m olecules a n d gold n a n o p artic les w e re u sed as a cc e p to r A. W e four

th a t th e ex p erim e n tal Forster critical tra n sfe r d ista n ce R0 is 1 -1 0 n m w h e n b o th D an d A a re dye mi

Iecules, a n d beco m es la rg e r th a n 10 n m w h e n th e d o n o r is flu o resc en t n a n o p articles. W h en th e accepto

A a re gold nan o p articles, th e case is c o n sid ered as localized p lasm o n coupled n an o su rface e n erj

tra n s fe r (NSET), th e ex p erim e n tal critical d istan ce d 0 increases u p to few te n n a n o m e te rs w h e n D a re dj

m olecules o r q u a n tu m dots. For th e first tim e, u n -e x p e c te d g ia n t re so n an c e en erg y tra n s fe r (G-RE￾p h e n o m e n o n is observed in o u r e x p erim e n ts w ith v e ry large critical tra n sfe r d istan ce d 0, w h ic h increasi

from few te n n a n o m e ters to m ic ro m e te rs w h e n th e d o n o rs a re flu o resc en t a n d th e a ccep to rs are goi

n an o p articles. A m odel “n anow ave e m itte r statio n a n d a n te n n a " is given to e xplain th e local field d<

p e n d en c e of th e critical distance of en erg y tra n s fe r b e tw e e n th o se n a n o p articles. M oreover, a sim p

th e o re tic al m odel w ith s iz e -n u m b e r c o n trib u tio n (for flu o resc en t n a n o p artic les) a n d surface plasm o

coupled e n h a n c e m e n t effect (for gold n an o p artic les) is p ro p o se d to explain th e se o b ta in e d e x p e rim e n t

results.

© 2015 Elsevier B.V. All rig h ts reservei

. Introduction

Fluorescence or Forster resonance energy tran sfer (FRET) has

een w idely used in biology and chem istry for m easuring the

¡stance r betw een tw o fluorophores to d etect m olecular inter￾ctions in a n u m b er of system s, th an k s to th eir d istance-depen￾en t d ipole-dipole interaction m echanism . FRET can be used as

Dectroscopic ru ler in various areas such as th e interaction of

iological m olecules in vitro and in vivo assays in cellular research,

ucleic acid analysis, signal transduction, light harvesting and

letallic nanom aterial etc. Based on th e m echanism of FRET a

iriety of novel chem ical sensors and biosensors have been de-

;loped [1-5]. Conventional FRET exhibits th e R~6 dependence

w of energy transfer rate and characterized by th e Forster dis￾ince or critical distance R0, w hich defined as th e distance at

'hich th e energy transfer efficiency is 50%. The R0 is given by

3 = 0.211 p n - V a / W ) ] 1'6 (1)

w here <f)D is the fluorescence q u an tu m yield of th e donor (D) in th

absence of th e acceptor (A), k2 is the dipole orientation factor, n i

th e refractive index o f th e m edium , and J{,t) is th e spectral overla

integral, /c2 = 2/3 for isotropically oriented dipoles [6]. The FRE

suffers from a lim ited length scale of approxim ately 10 nm . On th

o th er hand, th ere are m any w orks d em o n strated th e non-Forste

distance depen d en ce o f energy transfer. Bagchi et al. show ed th

R~2 depen d en ce rule for electronic excitation tran sfer (EET) from

seg m en t of polyfluorene to tetraphenylporphyrin. The Forste

expression seem s to be in ap p ro p riate for th e condensed-phas

system s w h ere donors and acceptors can be closely packed [7

The Forster energy tran sfer is also breaking dow n w h en th e energ;

transfer occurs from a dye m olecule to a n anom etal surface, whicl

w as attrib u ted to th e surface energy tran sfer (SET) and follows R~

distance dependence. This p h en o m en o n w as explained by thi

surface plasm on coupled nonradiative energy tran sfer [8,9]. En

ergy transfer betw een dye m olecules or q u an tu m dots (QDs) -

donors and m etallic nanoparticles (MNPs) - acceptors dem on

strates a longer range energy tran sfer p h en om enon due to th<

* Corresponding author.

E-mail address: [email protected] (T. Hong Nhung).

tp://dx.doi.oi‘g/10.l0l6/j.optcom.2015.05.015

)30-40181© 2015 Elsevier B.V. All rights reserved.