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