Journal of Materials Science: Materials in Electronics

Supporting Information for:

Effects of Donor Position on Dibenzofulvene-Based Organic Dyes for

Photovoltaics

Giuseppina Anna Corrente,a,b, Eduardo Fabiano,b,d Luisa De Marco,b Gianluca Accorsi,a Roberto

Giannuzzi,b Antonio Cardone,e Giuseppe Gigli,a,f Giuseppe Ciccarella,a,g Agostina-Lina

Capodilupo.a*

Giuseppina Anna Corrente a,b,c a CNR NANOTEC - Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via

Monteroni - 73100 Lecce Italy. b Center for Biomolecular Nanotechnologies (CBN) Fondazione Istituto Italiano di Tecnologia

(IIT), Via Barsanti 1, Arnesano, 73010, Italy. c Dipartimento di Ingegneria dell'Innovazione, Università del Salento, via Monteroni, 73100, Lecce,

Italy.

Eduardo Fabiano b,d b Center for Biomolecular Nanotechnologies (CBN) Fondazione Istituto Italiano di Tecnologia

(IIT), Via Barsanti 1, Arnesano, 73010, Italy. d Institute for Microelectronics and Microsystems (CNR-IMM), Via Monteroni, Campus

Unisalento, 73100 Lecce,

Luisa De Marco b b Center for Biomolecular Nanotechnologies (CBN) Fondazione Istituto Italiano di Tecnologia

(IIT), Via Barsanti 1, Arnesano, 73010, Italy.

1 Gianluca Accorsi a a CNR NANOTEC - Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via

Monteroni - 73100 Lecce Italy.

Roberto Giannuzzi b b Center for Biomolecular Nanotechnologies (CBN) Fondazione Istituto Italiano di Tecnologia

(IIT), Via Barsanti 1, Arnesano, 73010, Italy.

Antonio Cardone e

Istituto di Chimica dei Composti OrganoMetallici (ICCOM) – Consiglio Nazionale delle Ricerche

CNR, via Orabona, 4 – 720125 Bari, Italy.

Giuseppe Gigli a,f a CNR NANOTEC - Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via

Monteroni - 73100 Lecce Italy. f Dipartimento di Matematica e Fisica ”Ennio De Giorgi”, Università del Salento, via Monteroni,

73100, Lecce, Italy.

Giuseppe Ciccarella a,g a CNR NANOTEC - Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via

Monteroni - 73100 Lecce Italy. g Dipartimento di Scienze e Tecnologie Biologiche e Ambientali Universita' del Salento c/o Edificio

"La Stecca" via Monteroni, 73100 Lecce, Italy.

Agostina Lina Capodilupo a*

2 a CNR NANOTEC - Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via

Monteroni - 73100 Lecce Italy. E-mail: [email protected]

Corresponding author: E-mail: [email protected].

3 Contents of Supporting Information:

Figure S1. Electronic absorption spectra of dyes in DMSO solution at room temperature. Figure S2. Electronic absorption spectra of dyes in chlorobenzene solution at room temperature.

Figure S3. Emission spectra (λexc = 430 nm) of dyes. in three different polarity solvent (left: CB, middle: DCM, right: DMSO) at room temperature. Table S1. Photophysical data at room (298 K) temperature in three different polarity solvents. Figure S4. Excitation spectra of dyes. Figure S5. Cyclic voltammograms of dyes TG1-TG4. Table S2. Excitation energies calculated with the M06-2X exchange-correlation functional.

1 13 Figure S6. H NMR and C NMR spectra of 1a in CDCl3.

1 13 Figure S7. H NMR and C NMR spectra of 1b in CDCl3 Figure S8. 1H NMR and 13C NMR spectra of TG1 in DMSO. Figure S9. 1H NMR and 13C NMR spectra of TG2 in DMSO

1 13 Figure S10. H NMR and C NMR spectra of 2a in CDCl3

1 13 Figure S11. H NMR and C NMR spectra of 2b in CDCl3

1 13 Figure S13. H NMR and C NMR spectra of 3b in CDCl3 Figure S14. 1H NMR and 13C NMR spectra of TG3 in DMSO Figure S15. 1H NMR and 13C NMR spectra of TG4 in DMSO

4 Figure S1. Electronic absorption spectra of dyes in DMSO solution at room temperature.

Figure S2. Electronic absorption spectra of dyes in chlorobenzene solution at room temperature.

Figure S3 displays the luminescence spectra of all the samples in three different solvents. The corresponding photoluminescence quantum yields (PLQY) and lifetimes have been also obtained and reported in Table 3. For all the samples, the emission origin can be ascribed to the ICT states.

As for the absorption, the solvent polarity induces, in TK2 and TK3, the formation of different conformers emitting at different energies. In particular, by increasing the solvent polarity

(CBDCMDMSO) the emission profiles move to the red spectral window. On the contrary, TG1 and TG2 are mainly unaffected. Finally, the emission intensities (Table 3) indicate that TG3 and

TG4 are basically not emitting in all the conditions, while the reference samples (TG1 and TG2) and TK2-TK3 show the strongest emission in CB and DCM and in polar solvent (DMSO), respectively. The lifetime decays are also affected by the environment polarity as clearly showed in

Table 3. While in CB and DCM the values are comparable, in the most polar solvent (DMSO) the decays are ca. one order of magnitude shorter.

5 Figure S3 Emission spectra (λexc = 430 nm) of dyes. in three different polarity solvent (left: CB, middle: DCM, right: DMSO) at room temperature.

Table S1. Photophysical data at room (298 K) temperature in three different polarity solvents.

Dyes CB CB CB DCM DCM DCM b DMSO DMSO DMSO

λem/nm Φem/% τS/ps λem/nm Φem/% τS/ps λem/nm Φem/% τS/ps TG1 545 0.03 <30 536 0.01 <30 a a a TG2 580 3.6 350 589 3.9 310 542 0.09 < 30 TK2 556 1.1 6150 583 1.0 7800 624 1.5 700 TK3 560 1.0 6600 582 0.5 7.200 625 2.4 515 TG3 b b b b b b b b b TG4 b b b b b b b b b

a = Too weak signal; b = Not emitting

The excitation spectra have been also recorded in dichloromethane solution (Fig.S, TG3 and TG4 are not emitting) showing overlap with the corresponding absorption profiles. This indicates that both the ligand centred (LC) and ICT excited states contribute to the emission output

Figure S4. Excitation spectra of dyes.

6 Figure S5. Cyclic voltammograms of dyes TG1-TG4.

7 Table S2 Excitation energies, oscillator strenghts (o.s.), obtained from M06-2X TD-DFT calculations. Dye Energy (nm) o.s. TG1 434 0.43 250 0.40 TG2 478 0.67 350 0.06 243 0.52 TG3 406 0.21 387 0.55 347 0.67 TG4 463 0.51 388 0.48 345 0.54 286 0.18 TK2 545 0.31 503 0.14 365 0.18 318 0.34 TK3 572 0.40 469 0.13 387 0.28 325 0.42

10 TG1

11 Figure S8. 1H NMR and 13C NMR spectra of TG1 in DMSO.

12 TG2

Figure S9. 1H NMR and 13C NMR spectra of TG2 in DMSO

17 TG3

18 TG4