Scientists Researching a New Method for Harvesting the Sun's Energy

26th Feb 2013

Scientists from the Departments of Chemistry, Chemical Engineering, and Materials at the University of California Santa Barbara (UCSB) are researching a completely new method for harvesting the sun’s energy.

Martin Moskovits, a professor of Chemistry at UCSB, stated that, “it is the first radically new and potentially workable alternative to semiconductor-based solar conversion devices to be developed in the past 70 years or so.”

Traditional photoprocesses use a technology that was developed over many decades. Sunlight hits a semiconductor material and the photon excites the electrons causing them to jump out of their atoms and leave positively charges ‘holes’. This creates a current as other electrons move to fill in the gaps in the atoms.

The new technology does not use a semiconductor material, but rather nanostructured metals (gold nanorods). Moskovits explained that, “when nanostructures, such as nanorods, of certain metals are exposed to visible light, the conduction electrons of the metal can be caused to oscillate collectively, absorbing a great deal of the light. This excitation is called a surface plasmon.”

As the electrons are heated by the photons, some of them travel up the nanorod through a filter layer of crystalline titanium dioxide, and are then captured by platinum particles which coat the exterior of the rod. The energy can be used to split water into to hydrogen, which can be used as a fuel source, and oxygen.

This method of harvesting the suns energy is currently less efficient and more expensive than conventional methods, but given a few decades of innovation and research, the cost is expected to fall dramatically as the efficiency increases.

By. Joao Peixe