Hybrid Material Solves the Solar-Cell Dichotomy

摘要

Solar cells can either be made from inorganic compounds, which perform well but are costly to fabricate, or polymeric organic compounds, which are cheap but have poor energy efficiencies. Conventional inorganic solar cells can routinely convert 10% of the light falling on them into electrical energy, and some can even reach as high as 30%, but they require complex processing methods like those used to manufacture computer chips. On the other hand, organic polymers are not limited in this way, but they struggle to reach efficiencies of 2%. Inorganic materials perform better because they can transport charges to the electrodes more quickly, thereby reducing the losses that accrue from a recombination of negative electrons and positive holes. In contrast, electrons move relatively slowly down a conjugated polymer, and along the way they are prone to meet up with destructive entities such as oxygen. One answer is to blend into the polymer small molecules with conjugated systems; these allow electrons to find quicker routes to the desired destination. Even so, they may still guide the electron to a dead end.