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

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)

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

Why we are interested THE HAMMER RESEARCH GROUP John V. Garcia, Fan Zhang, Peter C. Ford, Phil. Trans. R. Soc. A, 2013, 371 20120129; DOI: 10.1098/rsta.2012.0129

THE HAMMER RESEARCH GROUP System

THE HAMMER RESEARCH GROUP System

THE HAMMER RESEARCH GROUP System

THE HAMMER RESEARCH GROUP Computations HOMO LUMO

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

THE HAMMER RESEARCH GROUP Absorption

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

THE HAMMER RESEARCH GROUP Φ = 3.51% τ1 = 1.22 ns τ2 = 11.42 ns Φ = 0.21% τ1 = 0.51 ns

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

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

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

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

THE HAMMER RESEARCH GROUP Single Molecule

THE HAMMER RESEARCH GROUP Φ = 3.51% τ1 = 1.22 ns τ2 = 11.42 ns

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

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

THE HAMMER RESEARCH GROUP Questions?