Discipline: Technology and Engineering
Subcategory: Chemistry (not Biochemistry)
Niloufar Jafari - Houston Community College
Co-Author(s): Shams Albayati, Texas A&M University, College Station, TX
During the recent years, researchers have been trying to find new ways to improve the power conversion efficiencies (PCEs) of the organic photovoltaics (OPVs). The OPVs have demonstrated PCEs above 12% in the recent studies. Current research have demonstrated that conjugated polymers additives can be used to enhance light absorption and facilitate charge separation in polymer/fullerene solar cells. However, there is a lack of understanding in how polymer additives impacts on photoactive layer morphology. The ideal active layer morphology of OPVs plays an important role on the photovoltaic properties of an organic solar cell. The achievement of thermally-stable equilibrium of a donor (PTB7)/ acceptor (Phenyl-C61-Butyric acid Methyl ester (PCBM)) morphology with continuous inter-penetrable networks, high interfacial areas and nanoscale sized domain can advance the OPVs performance. The structure of PTB7 have a branched side chains in ester and benzodithiophene. PTB7 provided the polymer good solubility in organic solvents. In this study, we investigate the effect of poly[N-90-heptadecanyl-2,7-carbazole- alt-5,5-(40 ,70 -di-2-thienyl-20 ,10 ,30 -benzothiadiazole)] (PCDTBT) in PTB7/PCBM solar cells. Here, we designed blends that contain different ratios of the PTB7, PCDTBT and PCBM. The inclusion of PCDTBT improves the charge separation, the electronic properties and the photovoltaic performance of PTB7/PCBM solar cells. PCDTBT is used as surface compatibilizer modulating the morphology PTB7 and PCBM solar cells to increase the current (Jsc) and fill factor (FF) of solar cells. In current work, we are investigating the effect of different ratios of the blends between the PTB7, PCDTBT, and PCBM to produce a more efficient solar cell. Our results so far had shown that adding more PCDTBT to the blends of PTB7 and PCBM is decreasing the current and increasing the voltage. We believe this happened because the ratios are not optimized. Therefore, to improve the solar cell performance we are investigating different ratios of PTB7, PCDTBT and PCBM. In conclusion, controlling the active layer morphology and developing ternary blend can enhance the electronic properties of OPVs solar cells. Therefore, we are developing different compositions of PCDTBT, PTB7, and PCBM to increase the PCEs.
Funder Acknowledgement(s): This work was supported by the National Science Foundation (NSF) as part of the Research Experiences and Exploration in Materials Science (REEMS) for Houston Community College Science and Engineering Students NSF DMR-1460564. This work was also supported by the NSF DMR-1352099, CBET-1264703, and the Welch Foundation for Chemical Research C-1888.
Faculty Advisor: Rafael Verduzco, firstname.lastname@example.org
Role: I have made various sets of solar cells containing different solutions of PCDBT, PCBM, and PTB7. Also, I have tested the organic photovoltaics (OPVs) to measure the power conversion efficiencies (PCEs) of each cell.