UNIVERSITY of CALIFORNIA, SANTA BARBARA

Due to the increased demand for renewable energy sources, the manufacturing of solar cells and photovoltaic devices has been steadily progressing in recent years. Organic photovoltaic (OPV) devices based on pi-conjugated polymer and fullerene composites, so-called ‘‘bulk heterojunction (BHJ)’’, offer an intrinsically low-cost, scalable approach to photovoltaic technology. Blends of thiophene-based polymers and fullerene composites are important materials used for fabricating BHJ solar cells. Recently, synthetic effort has focused on improving the power conversion efficiencies (PCEs) by means of development of low band-gap polymers and fullerene derivatives. Rod–coil block copolymers containing a rigid conjugated polymer segment as a rod block possess the ability to self-organize and be used to optimize the morphology in OPV devices. Reports on rod–coil block copolymers based on P3HT rods and polyolefin coils by using living radical polymerization techniques have established the existence of nanofibrilar structures in the solid state.  Historically, donor–acceptor rod–coil diblock copolymers containing C60 as the active layer in solar cells have been limited by the difficulty in removing unreacted C60.

Researchers at the University of California, Santa Barbara have developed a novel method for the synthesis of a well-defined donor–acceptor rod–coil diblock copolymer based on P3HT containing C60 through a living polymerization strategy.  Despite the bulky nature of the rigid C60 units in the coil blocks, the observation of nanofibrilar morphology with corresponding enhancement in performance of BHJ material is demonstrated. The novel diblock copolymers play a critical role in tuning the device morphology, leading to stabilization of the device structure against thermal phase integration.

•    Low cost, scalable approach

•    Organic photovoltaic devices

Categorized As

• Energy
  • Other
• Environment
  • Other
• Materials & Chemicals
  • Other

Related cases

2009-294-0

Keywords

Photovoltaic, Copolymer, Solar, Cell