The combination of mass-production compatible coating techniques and environmentally friendly solvents to process bulk heterojunction solar cells represents a key issue to scale up this technology. In this work we demonstrate that using a benchmark polymer HBG-1 blended with PC61BM, the replacement of a common chlorinated processing solvent (orthodichlorobenzene) with a non-chlorinated analogous (o-xylene) not only allows the fabrication of blade-coated bulk heterojunction devices with identical photovoltaic performance, but also determines a great enhancement of the resulting thermal stability. Thermal degradation tests were carried out in inert atmosphere, by keeping the solar cells onto a hot plate at 85 °C and monitoring their OPV performance. In parallel, the morphological changes of the active layers induced by thermal stress are investigated by combining two complementary light-based imaging techniques, laser scanning confocal and photocurrent microscopy, which offer the great advantage to simultaneously study on complete devices the blend morphology and the electrical properties, point-by-point, of the active layer even in regions unlikely accessible (e.g. the active area under the top electrode) using other techniques. As a result, we found that solar cells processed from a non-chlorinated based solvent, in comparison to an analogous reference system, exhibit a different evolution of the resulting BHJ morphology during thermal ageing, in perfect agreement with the corresponding photovoltaic responses.
Impact of environmentally friendly processing on polymer solar cells: Performance, thermal stability and morphological study by imaging techniques / Bolognesi, Margherita; Prosa, Mario; Tessarolo, Marta; Donati, Giovanni; Toffanin, Stefano; Muccini, Michele; Seri, Mirko. - In: SOLAR ENERGY MATERIALS AND SOLAR CELLS. - ISSN 0927-0248. - ELETTRONICO. - 155:(2016), pp. 436-445. [10.1016/j.solmat.2016.06.044]
Impact of environmentally friendly processing on polymer solar cells: Performance, thermal stability and morphological study by imaging techniques
TESSAROLO, MARTA;
2016
Abstract
The combination of mass-production compatible coating techniques and environmentally friendly solvents to process bulk heterojunction solar cells represents a key issue to scale up this technology. In this work we demonstrate that using a benchmark polymer HBG-1 blended with PC61BM, the replacement of a common chlorinated processing solvent (orthodichlorobenzene) with a non-chlorinated analogous (o-xylene) not only allows the fabrication of blade-coated bulk heterojunction devices with identical photovoltaic performance, but also determines a great enhancement of the resulting thermal stability. Thermal degradation tests were carried out in inert atmosphere, by keeping the solar cells onto a hot plate at 85 °C and monitoring their OPV performance. In parallel, the morphological changes of the active layers induced by thermal stress are investigated by combining two complementary light-based imaging techniques, laser scanning confocal and photocurrent microscopy, which offer the great advantage to simultaneously study on complete devices the blend morphology and the electrical properties, point-by-point, of the active layer even in regions unlikely accessible (e.g. the active area under the top electrode) using other techniques. As a result, we found that solar cells processed from a non-chlorinated based solvent, in comparison to an analogous reference system, exhibit a different evolution of the resulting BHJ morphology during thermal ageing, in perfect agreement with the corresponding photovoltaic responses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.