Increasing solar efficiencies by reducing different between HOMO & LUMO level

A common way to increase the solar cell efficiencies is to adjust the differences between HOMO and LUMO level of the polymer so that the excitons can be harvested with minimal lost. A fluorine atom is usually added to polymer backbone but it is a multistep process and has a considerable fabrications cost.   

A team of chemists led by Jianhui Hou from the Chinese Academy of Sciences created a polymer known as PBT-OP from two commercially available monomers and one easily synthesized monomer. Wei Ma, a post-doctoral physics researcher from NC State and corresponding author on a paper describing the research, conducted the X-ray analysis of the polymer's structure and the donor:acceptor morphology.

PBT-OP was not only easier to make than other commonly used polymers, but a simple manipulation of its chemical structure gave it a lower HOMO level than had been seen in other polymers with the same molecular backbone. PBT-OP showed an open circuit voltage (the voltage available from a solar cell) value of 0.78 volts, a 36 percent increase over the ~ 0.6 volt average from similar polymers.

Read more at: http://phys.org/news/2014-01-simple-cheap-solar-cell-efficiency.html#jCp

Self-Healing Polymer 'Terminator Polymer'

This is a neat trick. After slicing a tube of gelatinous material in half with a razor, researchers stick the two pieces back together again. After they've sat together for two hours at room temperature, the pieces are impossible to pull apart. The material, a new invention, has healed itself:

Self-healing materials like this would be useful in so many places. They could keep tablets, phones and other everyday objects from sustaining nicks and scratches. Even NASA studies self-healing materials because they could reduce the need for costly and dangerous repairs in tough environments, i.e., space. Many labs around the world are working on different versions of this.

The material shown above, invented by a team of materials scientists from the IK4-CIDETEC Research Center in Spain, is one of the first that is able to heal itself without the help of heat, light, added chemicals or other interventions, according to Chemistry World. (Self-healing materials often need some kind of catalyst to trigger the changes in chemistry required to bond broken pieces back together again.)

Source: http://www.popsci.com/science/article/2013-09/watch-weird-gelatinous-material-heal-itself?src=SOC&dom=fb