Ultrafast coherent energy transfer Gregory D. Scholes Department of - PowerPoint PPT Presentation

Ultrafast coherent energy transfer Gregory D. Scholes Department of Chemistry, University of Toronto 1

e group now: Alumni: Collaborators: Yasser Hassan Karyn Ang National Renewable Energy Laboratory Vanessa Huxter Dr. Vitalij Kovalevskij Garry Rumbles Yaser Khan Dr. Peggy Hines Anna Lee Dr. Alexander Doust Università di Pisa Shun Lo Dr. Xiujuan Yang Benedetta Mennucci Michelle Nagy Dr. Karolina Fritz Megan Oh Dr. Sree Nair University of New South Wales Cathy Wong Dr. Sandeep Kumar Paul Curmi Dr. Mayrose Salvador Krystyna Wilk Dr. John Casey Dr. Tieneke Dykstra Dr. Carles Curutchet Dr. Elisabetta Collini University of Mons David Beljonne Dr. Jun He Dr. Tihana Mirkovic Dr. Marcus Jones University of Houston Dr. Jeongho Kim Eric Bittner Dr. Haizheng Zhong 2

1923–29 J. Perrin, F. Perrin, • Observed concentration S.I. Vavilov quenching of dye fluorescence H. Kallmann & F. • Proposed a quantum 1929 London; Ya. Frenkel mechanical coupling between donor and acceptor • Energy migration depolarizes Vavilov & Galanin 1940s fluorescence • Spectral overlap condition Emerson & Arnold • FRET in biological systems 1932 • Quantum mechanical coupling 1948 Th. Förster + spectral overlap FRET 3

J. Phys. Chem. B 113, 6583–6599 (2009). 4

Natural PV: photosynthesis employs specialized energy funnels 5

Birstonas, Lithuania September 1996 ESF Workshop (Valkunas and van Grondelle) “... The discovery of these structures has strongly stimulated the analysis of the physical processes responsible for the rapid migration of energy in photosynthesis” “Major questions concern...time over which the excitation must be considered as coherent...” 6

Nature, 431, 256–257 (2004). 7

Natural nanoscale systems Elisabetta Collini, Carles, Curutchet, et al. Proceedings from the Paris Research Center Workshop on Energy Flow Dynamics in Biomaterial Systems (2008). 8

Light-harvesting in nature Elisabetta Collini (2008) 9

Cryptophyte marine algae Rhodomonas CS24 periplast ejectosome flagella gullet Tihana Mirkovic, et al. Photosynthesis Res. (2009). 10

Rhodomonas CS 24 (a cryptophyte) Alexander Doust, et al. J. Mol. Biol. (2004) 11

Structural model of PC645 ( Chroomonas ) 12

Assign the spectrum to structure 13

Assign the spectrum to structure DBV PCB MBV 14

Coherence in cross-peak beats 1 A ∗ B − AB ∗ � � Ψ − = √ 2 1 A ∗ B + AB ∗ � � Ψ + = √ 2 15

Electronic beats 1 � A ∗ B − AB ∗ � = √ 2 A ∗ , B ∗ 1 � A ∗ B + AB ∗ � = √ 2 Ψ α =1 = c a φ a + c b φ b + ρ α =1 = c a c ∗ ab b 16

Need information at the amplitude level population/polarization grating 17

Two-dimensional photon echo (2DPE) τ T 18

Interpreting 2DPE data 19

Rephasing vs. non-rephasing signals Yuan-Chung Cheng & Graham Fleming 20

Coherence pathways in the signals Yuan-Chung Cheng & Graham Fleming 21

2DPE signals (real part) decomposed 22

2D-2PE (real part) PC645 antenna 293K from the left top to the right bottom T= 0, 6, 10, 20, 30, 40,50, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 500, 600, 700, 800, 900 fs, 1ps, 2ps, 5ps. 23

Electronic beats: rephasing spectra 24

Electronic beats 25

Electronic beats: rephasing spectra 26

Coherence beats (PC645): non-rephasing 2.185 eV ~600 cm –1 2.11 eV 2.11 eV 2.06 eV 2.06 eV 2.185 eV 27

Coherence beats (PC645): non-rephasing 2.185 eV ~600 cm –1 2.11 eV 2.11 eV 2.06 eV 2.06 eV 2.185 eV ~380 cm –1 2.11 eV 2.06 eV 2.185 eV 28

Coherently ‘wired’ energy migration 29

Quantum probability amplitudes Classical: P = P (d-a) + P (d1-d2-a) + ... Quantum: P = | G (d-a) + G (d1-d2-a) + ... | 2 R. P. Feynman, Rev. Mod. Phys. (1948). Time (ps) 30

Weak and strong coupling regimes 31

Limits of the dynamics strong electronic weak electronic coupling coupling Förster theory Redfield theory, etc 32

PC645 trajectories: weak coupling to MBV 18.0 E α =3 17.5 Energy E α =2 3 x10 17.0 E α =1 16.5 16.0 0 2000 4000 6000 8000 10000 Time (fs) 0.0 -0.1 ρ α =1 -0.2 ab -0.3 -0.4 0 2000 4000 6000 8000 10000 Ψ α =1 = c a φ a + c b φ b + c c φ c ρ α =1 = c a c ∗ ab b 33

PC645 trajectories 18.0 17.5 Energy 3 17.0 x10 16.5 16.0 0 2000 4000 6000 8000 10000 Time (fs) 0.0 ρ α =1 -0.1 -0.2 ab -0.3 -0.4 0 2000 4000 6000 8000 10000 34

What limits the exciton diffusion length? ultrafast energy relaxation/transfer 35

Energy migration along a PPV chain 36

Energy transfer in PPV chains Jay Singh, Eric Bittner, David Beljonne, GDS (2009). 37

Ultrafast anisotropy decay 38

Photon echo spectroscopy population/polarization grating 39

Coherence-mediated energy transfer 293 K Elisabetta Collini & GDS, Science 323, 369–373 (2009). J Phys Chem A 113, 4223–4241 (2009). 40