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Quantum mechanical study and modelling of structural electronic optical and transport properties of organic semiconductors and their interfaces with silicon, silicon dioxide, graphene and polymers

Keywords: semiconductors, interfaces, OPV, OFET
Fig. 1. Primitive cell of crystalline PCBM with diclorobenzene molecules from QM calculations (Author: Renato Colle).
Fig. 2. Interface of an organic field-effect transistor. Current flowing along the x direction (Author: Renato Colle).

The aim of this research is the quantummechanical study, interpretation and prediction of structural, electronic, optical and transport properties of crystalline organic semiconductors, used for photovoltaic cells (OPV) and organic electronic devices (OFET), and of their interfaces with silicon, silicon dioxide and polymers. This research aims also to use knowledges acquired on these materials to work out models useful to simulate and interpret the internal mechanisms of electronic devices such as OPV and OFET. The materials considered are those of major interest for organic electronics and solar cells: (1) crystalline organic semiconductors, such as Perylendiimides (PDI-FCN2), PCE10, Rubrene that are prototypes of nchannel and p-channel materials for OFET; (2) pairs of e-donor/-acceptor crystalline organic materials for “Bulk HeteroJunction” (BHJ) solar cells, such as P3HT(polymer) / PCBM (fullerene derivative); (3) ionic liquid crystalline materials, such as “dicationic thienoviologen salts” of different alkyl-chain lengths, that selfassemble into either calamitic or columnar mesophases, and are used in the new interdigitated BHJ OPV; (4) Pristine graphene strongly interacting with inorganic substrates which enhance its chemical reactivity. In the study of these materials, large attention is devoted to the structure and properties at interfaces, such as edonor/ e-acceptor, organic semiconductor / metallic electrode or insulating substrate.

These research projects are carried out in collaboration with research groups of the Department of Physics, University of Pisa (activities 1, 2, 4) and the Department of Chemistry, University of Calabria (activity 3).

Main publications

R. Colle, G. Menichetti, and G. Grosso: “Graphene on clean (0001) alpha-quartz: Numerical determination of a minimum energy path from metal to semiconductor” Physica Status Solidi B, 1-9 (2016) / DOI 10.1002/pssb.201600111.

G. Menichetti, R. Colle, C. Gatti, and G. Grosso: “Heterointerface Electronic States and Charge Transport of Crystalline N,N-1H,1H-Perfluoro butil Dicyanoperylene Diimide in Field-Effect TransistorConfiguration” The Journal of Physical Chemistry C (2016) DOI 10.1021/acs.jpcc6b03454.

R. Colle, G. Grosso A. Cassinese, and R. Centore: “Structural, electronic and vibrational properties of N,N-1H,1H-perfluorobutyl dicyanoperylene carboxy diimide (PDI-FCN2) crystal” The Journal of Chemical Physics 139, 114507 (2013).

R. Colle, G. Grosso, A. Ronzani, M. Gazzano, V. Palermo: "Anisotropic molecular packing of soluble C60 fullerenes in hexagonal nanocrystals obtained by solvent vapor annealing". Carbon 50, 1332-1337 (2012).

R. Colle, G. Grosso, A. Ronzani, C.M. Zicovich- Wilson: "Structure and X-ray spectrum of crystalline poly(3-hexylthiophene) from DFT-Van der Waals calculations". Phys. Status Solidi B 248, No.6, 1360-1368 (2011).

G. Cinacchi, R. Colle, P. Parruccini, A. Tani: "Structural, electronic and optical properties of a prototype columnar discotic liquid crystal". J.Chem.Phys. 129, 174708-1,8 (2008).

C. Cavazzoni, R. Colle, R. Farchioni, and G. Grosso: "Acidification of three-dimensional Emeraldine polymers: search for minimum energy paths from base to salt". J.Chem.Phys. 128, 234903-1,5 (2008).

E. Gnani, S. Reggiani, A. Gnudi, R. Colle, G. Baccarani: "OH dangling-bond saturation and dielectric function effects in ultra-scaled SNWFETs". Proc. of the Device Research Conference. Device Research Conference (DRC-2008). Santa Barbara, CA 23-25 June, 2008 (pp. 95-96). SANTA BARBARA, CA:IEEE Press.

R. Colle, P. Parruccini, A. Benassi, and C. Cavazzoni: "Optical properties of emeraldine salt polymers from ab initio calculations: comparison with recent experimental data". J.Phys.Chem.B 111, 2800-2805 (2007).

C. Cavazzoni, R. Colle, R. Farchioni, and G. Grosso: "HCl doped conducting Emeraldine polymer by ab-initio Car-Parrinello molecular dynamics". Phys.Rev.B 74, 033103-1,4 (2006).

C. Cavazzoni, R. Colle, R. Farchioni, and G. Grosso: "Base and salt 3D forms of emeraldine II polymers by Car-Parrinello molecular dynamics". Comput.Phys.Comm. 169, 135-138 (2005).

G. Cinacchi, R. Colle, and A. Tani: "Atomistic Molecular dynamics simulation of hexapentyloxy- triphenylene: structure and translational dynamics of its columnar state". J.Phys.Chem.B 108, 7969-7977 (2004).

C. Cavazzoni, R. Colle, R. Farchioni, and G. Grosso: "Ab-Initio Molecular Dynamics Study of the Structure of Emeraldine Base Polymers". Phys. Rev. B 69, 115213-1,6 (2004).

C. Cavazzoni, R. Colle, R.F archioni, and G. Grosso: "Car-Parrinello Molecular Dynamics study of electronic and structural properties of neutral polyanilines”. Phys. Rev. B 66, 165110- 1,10 (2002).

Research projects

CINECA ISCRA 2016 Project: HP10CAI9P