Effect of molar mass and regioregularity on the photovoltaic properties of a reduced bandgap phenyl-substituted polythiophene

F. Ouhib , G. Dupuis , R. de Bettignies (1) , S. Bailly (2) , Abdel Khoukh (3) , Hervé Martinez (3) , Jacques Desbrieres (3) , Roger C. Hiorns (3) , Christine Lartigau-Dagron (3)

1 POMA - Propriétés Optiques des Matériaux et Applications
2 LAPTH - Laboratoire d'Annecy-le-Vieux de Physique Théorique
3 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Among the numerous reduced bandgap polymers currently being developed, poly[3-(4-octylphenyl)thiophene)]s (POPT) may present attractive properties for organic solar cells due to its facile preparation and improved absorption with respect to poly(3-hexylthiophene). This article appraises methods of preparation, including the use of diphenyl ether as a reaction medium, and discusses the effects of variations in molar masses, from about 3200 to 65,000 g mol -1 and regioregularity on its optoelectronic properties. The photovoltaic properties of POPT with [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) in bulk heterojunction devices are also discussed in the light of morphological variations, as indicated by atomic force microscopy characterizations. With an initial screening of conditions, namely POPT:PCBM ratios and deposition solvent, a power conversion efficiency of 1.58% was obtained using a relatively high molar mass POPT sample.

Mots clés: [6; 6]-phenyl C 61 butyric acid methyl ester (PCBM); Atomic force microscopy; Butyric acid; Chain-growth polymerization; chain growth polymerization polythiophenes; conjugated polymers; Conversion efficiency; Diagnosis; Energy gap; Esterification; Esters; Grignard metathesis; Grignard metathesis chain growth polymerizations; Heterojunctions; Methyl esters; Molar mass; Organic polymers; Photovoltaic devices; Photovoltaic effects; poly[3-(4-octylphenyl)thiophene]; Polymerization; Screening; Thiophene

Domaines: Chimie

F. Ouhib, G. Dupuis, R. de Bettignies, S. Bailly, Abdel Khoukh, et al.. Effect of molar mass and regioregularity on the photovoltaic properties of a reduced bandgap phenyl-substituted polythiophene. Journal of Polymer Science Part A: Polymer Chemistry, 2012, 50 (10), pp.1953--1966. ⟨10.1002/pola.25970⟩. ⟨hal-01499188⟩