Peidong Yang (USA)
Director of the Kavli Energy Nanoscience Institute (ENSI), Professor of University of California, Berkeley.
The Yang group has made significant contribution in the photovoltaic area by introducing for the first time the idea of nanowire solar cell. Within this first study, his group was able to clearly demonstrate the advantage of the nanowire solar cell over other nanoparticle based solar cells: the much improved charge transport. Additionally his group has introduced several new versions of nanowire solar cell design, including core-shell nanowire-dyesensitised solar cell; core-shell nanowire solar cells and their arrays with strong light trapping effect. Dr. Yang introduced the concept of “Systems Materials Engineering” approach towards solving such challenging scientific and technological problems (Nature Mater. 2012). Early 2013, his group reported the first fully integrated nanosystem for direct solar water splitting. Similar to the photosynthetic system in a chloroplast, this artificial photosynthetic system comprises two semiconductor light absorbers with large surface area, an interfacial layer for charge transport, and spatially separated cocatalysts to facilitate the water reduction and oxidation.
In 2015, Yang and his team have created a synthetic “leaf” that is a hybrid system of semiconducting nanowires and bacteria S. Ovata. The nanowires gather sunlight, and the bacteria trigger the use of carbon dioxide and water to complete the photosynthetic process and produce a targeted carbon-based chemical such as butanol. This is the first time that a fully integrated system was assembled to produce value-added chemicals directly and solely from CO2, H2O and sunlight, and is widely considered as one of the major breakthroughs in the field of artificial photosynthesis.
Another work of widespread influence from the Yang group is the synthesis of Si/Ge superlattice nanowires based on Vapour-Liquid-Solid (VLS) mechanism. His group then clearly demonstrated their size-dependent thermal conductivities and enhanced thermoelectric performance. His group has discovered that silicon nanowires with rough surface could have thermoelectric figure-of-merit ZT~0.6 at room temperature, two orders of magnitude better than that of bulk silicon (Nature, 2008, 451, 163 US patent 6,882,051 & 8,729,381). These Si nanowire arrays show great promise as high-performance, scalable thermoelectric materials for waste heat recovery in power plants, refineries and automobiles.