O BJECTS IN THE REAL WORLD VERSUS O BJECTS IN THE NANO WORLD Done by: Reynold 3P3 (19)

C OPPER

P ROPERTIES OF COPPER Hard vs. Soft In normal circumstances, as objects decrease in sizes (in other words, become finer), their mechanical strength increases. Copper do not differ. However, research have shown that at nanoscale, copper displays unexpected mechanical properties. Instead of increasing in mechanical strength, copper becomes softer instead. This happens when copper is as small as 15nm or smaller.

P ROPERTIES OF COPPER Electrical conductivity Research have shown that the electrical conductivity of copper is size-dependent. As the size of copper decreases, so does its electrical conductivity.

P ROPERTIES OF COPPER Appearance Copper in large sizes are opaque whereas in small sizes (nanorods/ nanowires), copper appear transparent.

N ANO COPPER IN USE … Nano copper can be used in/for… Making nano wires (next slide) Making conductive coating of metal and metalloid surface. Heat conduction and abrasion resistant

N ANO COPPER USED FOR MAKING NANO WIRES As nano copper is transparent, it is ideal for thin-film solar cells, flat-screen TVs and computers, and flexible displays. They perform better than the usual carbon nanotubes. In addition, they are much cheaper than the silver nano wires as they are abundant in the Earth’s crust and are easy to obtain.

N ANO COPPER USED FOR MAKING NANO WIRES However… They are brittle, making it unsuitable for flexible screens. The production process is inefficient. Its price is increasing due to increase in demand.

S ILICON

P ROPERTIES OF SILICON Electrical insulator vs. electrical conductor In large sizes, silicon are electrical insulators. Whereas in nanoscale, silicon conducts electricity instead.

N ANO SILICON IN USE … Nano silicon can be used in/for… Making solar energy conversion more efficient (in detail on next slide) Aiding tumor treatment (in detail on following slide)

N ANO SILICON INCREASES SOLAR - CELL EFFICIENCY In normal solar panels, each solar cells convert one photon to one electron Research have shown that one silicon nano- crystal can convert one photon to two to three electrons! This improves efficiency as the same amount of solar energy can be converted to more electrical energy. This efficiency is new and unheard of in the solar industry

N ANO SILICON AIDS TUMOR TREATMENT Nano silicon is porous and have pores that are so tiny only particles of atomic sizes can pass through This is helpful as it helps to control the right amount of drug released into the human body during surgery as only certain amount of particles, and particles of the right size, can pass through the nano-sized pores.

R EFERENCES Risø National Laboratory for Sustainable Energy (2009, February 5). Super Strong Nanometals: Ductile Copper Made Four Times Stronger Than Commercial Material. ScienceDaily. Retrieved June 7, 2010, from /releases/2009/02/ htm Jin Xuesong, X. H. (2008, February 5). The electrical conductivity characteristics of Fe/Cu nano-scale multilayer materials. Science in China Series E: Technological Sciences, 83-88

R EFERENCES Duke University (2010, June 2). Copper nanowires enable bendable displays and solar cells; Pin-like copper structures self-assemble in solution. ScienceDaily. Retrieved June 8, 2010, from /releases/2010/06/ htm

R EFERENCES Zhang, P. (n.d.). Nanotechnology research leads to molecular-scale batteries and motors. Retrieved June 8, 2010, from Engineer Live: Engineer/Materials_Handling/Nanotechnology_re search_leads_to_molecular- scale_batteries_and_motors/15635/ Shanghai Huzheng Nano Technology Co., Ltd. (2008, December 7). Nano copper powder and solution. Retrieved June 8, 2010, from himfr.com: Nano_copper_powder_and_solution/

Green, H. (2007, August 16). Silicon Nano Crystals Could Triple Solar Efficiency. Retrieved June 10, 2010, from Ecogeek: pSivida. (2004, June 18). Nano silicon boosts tumour fight. Retrieved June 10, 2010, from BBC News: