1. THE HAMMER RESEARCH GROUP
SPECTROSCOPIC INVESTIGATION OF NEWLY-DEVELOPED NEAR INFRARED EMITTING DYES
Louis McNamara
Nalaka Liyanage, Adithya Peddapuram,
Joseph S. Murphy, Jared H. Delcamp,
Nathan I. Hammer

2. THE HAMMER RESEARCH GROUP
Intro to NIR dyes
Energy-gap law inherently disfavors low energy band gaps
The most common strategy is large π-conjugated systems containing electron-donating (D) and accepting (A) groups
Donor-Acceptor-Donor (D-A-D)
Intramolecular charge transfer (ICT)

3. Why we are interested Night vision technologies Secure communications
THE HAMMER RESEARCH GROUP
Why we are interested
Night vision technologies
Secure communications
Fluorescence imaging
Transparent photovoltaics
Heat-blocking coating
In vivo fluorescence imaging

4. Why we are interested THE HAMMER RESEARCH GROUP
John V. Garcia, Fan Zhang, Peter C. Ford, Phil. Trans. R. Soc. A, 2013,  ; DOI:  /rsta

5. THE HAMMER RESEARCH GROUP
System

6. THE HAMMER RESEARCH GROUP
System

7. THE HAMMER RESEARCH GROUP
System

8. THE HAMMER RESEARCH GROUP
Computations
HOMO
LUMO

9. Computations Dye vert. trans. (nm, eV) oscillator strength angle 1 (o)
THE HAMMER RESEARCH GROUP
Computations
Dye
vert. trans. (nm, eV)
oscillator strength
angle 1 (o)
angle 2 (o)
TPz-Et
640, 1.94
0.59 19 -
TPz-CO2Et
781, 1.59
0.43
13, 18
29, 50
TPz-Ph
706, 1.76
0.41 20 41
TPz-Ph-OMe
683, 1.82
0.42 39
TPz-Ph-CO2Me
755, 1.64
0.33 21

10. THE HAMMER RESEARCH GROUP
Absorption

11. THE HAMMER RESEARCH GROUP
Φ = 2.16% τ = 1.12 ns
Φ = 0.86% τ1 = 0.60 ns
τ2 = 3.34 ns

12. THE HAMMER RESEARCH GROUP
Φ = 3.51% τ1 = ns
τ2 = ns
Φ = 0.21% τ1 = 0.51 ns

13. Dye Solvent QY(φ) (%) τ1 (ns) τ2 TPz-Et DMFa 1.63 0.85 N/A DMFb 2.05
THE HAMMER RESEARCH GROUP
Dye
Solvent
QY(φ)
(%) τ1
(ns) τ2
TPz-Et
DMFa
1.63
0.85
N/A
DMFb
2.05
0.92
CHCl3 a
2.16
1.12
CHCl3 b
2.25
1.09
MeOH/CHCl3 a
0.36
0.41
MeOH/CHCl3 b
0.45
0.52

14. Dye Solvent QY(φ) (%) τ1 (ns) τ2 TPz-Ph DMFa 2.13 0.44 14.58 DMFb 3.29
THE HAMMER RESEARCH GROUP
Dye
Solvent
QY(φ)
(%) τ1
(ns) τ2
TPz-Ph
DMFa
2.13
0.44
14.58
DMFb
3.29
0.65
13.68
CHCl3 a
3.51
1.22
11.42
CHCl3 b
4.29
1.23
13.04
MeOH/CHCl3 a
2.62
0.85
4.46
MeOH/CHCl3 b
3.74
1.02
7.11

15. Dye Solvent QY(φ) (%) τ1 (ns) τ2 TPz-PhOMe DMFa 0.56 0.50 N/A DMFb
THE HAMMER RESEARCH GROUP
Dye
Solvent
QY(φ)
(%) τ1
(ns) τ2
TPz-PhOMe
DMFa
0.56
0.50
N/A
DMFb
2.87
0.57
CHCl3 a
0.86
0.68
3.34
CHCl3 b
1.40
0.75
4.06
MeOH/CHCl3 a
0.34
0.55
MeOH/CHCl3 b
0.41

16. Dye Solvent QY(φ) (%) τ1 (ns) τ2 TPz-PhCO2Me DMFa 0.15 0.54 N/A DMFb
THE HAMMER RESEARCH GROUP
Dye
Solvent
QY(φ)
(%) τ1
(ns) τ2
TPz-PhCO2Me
DMFa
0.15
0.54
N/A
DMFb
0.21
0.61
CHCl3 a
0.51
CHCl3 b
0.26
0.58
MeOH/CHCl3 a
0.08
0.60
MeOH/CHCl3 b
0.12
0.63

17. THE HAMMER RESEARCH GROUP
Single Molecule

18. THE HAMMER RESEARCH GROUP
Φ = 3.51% τ1 = ns
τ2 = ns

19. Conclusions Stokes shifts near 200 nm achieved
THE HAMMER RESEARCH GROUP
Conclusions
Stokes shifts near 200 nm achieved
Good quantum yields at >4% in the NIR region (775 nm peak emission) observed
Emission of materials was stable in a solid film during irradiation
Molecules are part of design with potential applications in a range of devices

20. Acknowledgements FUNDING! CHE-0955550 CHE-1156713 EPS-0903787
THE HAMMER RESEARCH GROUP
Acknowledgements
FUNDING!
CHE
CHE
EPS

21. THE HAMMER RESEARCH GROUP
Questions?