Conjugated Polymer Photovoltaic Materials

The Institute of Organic Solids of the Chemistry Institute CAS
recently achieved major advances in the research of new
conjugated polymer photovoltaic materials for polymer solar
energy cells.
   The research team has designed and synthesized branch-chain
conjugated polythiophene containing a conjugated branch chain
(styrene or thiophene ethylene). Polythiophene derivatives with
broad or strong absorption coefficient in the visible zone can
be obtained by adjusting the length of the conjugated branch
chain or the ratio of thiophene elements on the branch chain.
Polythiophene containing a di-thiophene ethylene branch chain
displays a 380-650nm wide and strong absorption bar. Polymer
solar energy cells prepared through the blending of this polymer
with C60 derivative PCBM (weight ratio 1:1) has a maximum energy
conversion rate of 3.18% in simulated sunlight, being 38% higher
than that of poly(3-hexylthiophene) in popular use today.
   Besides, the research team has also made achievements in
conjugated polymer materials with high migration rate. It has
designed and synthesized a cross-linking polythiophene
derivative containing a conjugated bridging group. The cavity
mobility rate of polymers containing 5% conjugated bridge is 2
orders of magnitude higher than polymers with no conjugated
bridge. Their photovoltaic property is also greatly improved.