Tropes

R_www.rdmag.com 2015 00093.txt.txt

#Shortening Organic solar cell Production One of the building blocks of the solar panel, solar cells are responsible for converting solar energy into electricity. Most commercial solar cells are made from the inorganic crystalline silicon. Now, the U s. Dept of energy (DOE) Oak ridge National Laboratory (ORNL) has developed a method to save steps in the organic solar cell manufacturing process by introducing solvents into solar cell film production. Usually, the thin filmssed by organic bulk heterojunction solar cellsre created by mixing conjugated polymers and fullerenes, which the lab describes as occer ball-like carbon molecules known as buckyballs. After uniformity is achieved by spin casting the mixture on a rotating substrate the material is annealed. The annealing process reduces the material hardness, but increases its toughness. However, the new method allows scientists to bypass the thermal annealing process, allowing for both time and cost savings. Instead of using thermal annealing, the researchers added a solvent, which aided in dissolving fullerenes and made the film structure more uniform. Lack of uniformity in a film mixture causes clusters to form, which absorb electrons meant for conversion. According to researchers, the sample with the solvent additive was consistent throughout and performed better than the annealed sample. he reason is that when we use a solvent instead of annealing, the sample dries very slowly, so there is enough time for the system to become fully optimized, said Valeria Lauter, lead instrument scientist on the lab Magnetism Relectometer, which provided accurate depictions of the structural profiles of the samples. e see that additional annealing is not necessary because, in a sense, the system is already as perfect as it can be. According to the DOE, organic photovoltaic solar cells have low efficiencies due to their small excition diffusion lengths and low carrier mobilities. hese two characteristics result in the use of thin active layers that affect overall drive performance, according to the DOE. urthermore, the operational lifetimeemains significantly lower than for inorganic devices. However, the information obtained from the neutron reflectometry will help scientists boost organic solar cell performance, according to ORNL. ptimization of photovoltaic properties provides information to manufacture solar cells with fully controlled morphology and device performance, said Nuradhika Herath, the lead of the study. hese findings will aid in developing dealphotovoltaics, which gets use on step closer to producing commercialized devices. e

< Back - Next >