1. Chapter - 9 Energy Transfer Processes
1. Intermolecular (or atomic) energy transfer
1. Forster energy transfer
2. Dexter energy transfer
2. Intramolecular (or atomic) energy transfer
Advantages of Doped Emitter (H-G System):
Improved EL Efficiency
Color tuning
Improved EL Stability

2. Applications Aluminate Blue Phosphors for Fluorescent Lamps
Europium Activated Barium Magnesium Aluminate
(BaEu)MgAl10O17
2) Aluminate Green Phosphors for Fluorescent Lamps
Cerium and Terbium Activated Magnesium Aluminate
(Ce,Tb)MgAl11O19
3) Red Phosphors for Fluorescent Lamps
Europium Activated Yttrium Oxide
Y2O3:Eu
Red : Guest, Black : Host

3. bound electron-hole pairs
An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force.

4. Dexter, D.L J. Chem. Phys. 21:836
Förster, Th., Ann. Phys. 2:55

6. EE Electron Exchange

8. CI Coulombic Interaction

10. Derivation (Not for Examination)
The energy transfer from Donor to Acceptor molecules can be denoted as
D* + A  D + A*
Initial state (Before Energy Transfer)
ψi = 1/ √2 [ψD*(1) ψA(2) - ψD*(2) ψA(1)].
Final State ( After Energy Transfer )
ψf = 1/ √2 [ψD(1) ψA*(2) - ψD(2) ψA*(1)].

13. Rate of Energy Transfer (Not for Examination)

14. Forster Energy Transfer Rate (Not for Examination)

15. Förster distance (R0, nm)
Förster distances of different donor-acceptor pairs.
Donor
Acceptor
Förster distance (R0, nm)
Naphthalene
Dansyl
2.2 LY
TNP-ATP
3.5
ODR
4.3 EM
5.3
FITC
6.0
BPE
CY5
7.2
Abbreviations: BPE, B-phycoerythrin; CY5, carboxymethylindocyanine; Dansyl, just dansyl group; EM, eosin maleimide; FITC, fluorscein-5-isothiocyanate; LY, Lucifer yellow;ODR, octadecylrhodamine; TNP-ATP, trinitrophenyl-ATP.

16. Donor Acceptor Ro(Ǻ) Fluorescein Tetramethlrhodamine 55 IAEDANS 46
Typical values of R0
Donor
Acceptor
Ro(Ǻ)
Fluorescein
Tetramethlrhodamine 55
IAEDANS 46
EDANS
Dabcyl 33
Fluoresscein 44
BODIPY FL 57
Qsy7&Qsy9 dyes 61

17. Dexter Energy Transfer Rate (Not for Examination)

19. Doped Emitters