The desire to fabricate materials with novel or improved properties is a powerful stimulus for the development of materials science. Thermal and electrical conduction, optical response, energy conversion and storage are just a few of the large number of properties underwent a very fast evolution in the last decade thank to the birth of a new branch of materials science and technology defined “Nanotechnology”. Nanotechnology includes the totality of the physical, chemical, biological and engineering knowledge involving artificial structures whose properties are controlled at the nanometer level. Among the multitude of nanomaterials created, a particular class of them is becoming very popular and represents nowadays the most fascinating and potentially revolutionary inorganic semiconductor structure, which is the family of the colloidal quantum dots. They are often referred to as “nanocrystals” and the colloidal definition reveal their chemical origin. Actually, the chemical synthesis currently represents the most effective way to obtain high quality (in terms of size control, narrow size distribution, good crystalline structure and high optical performances) nano-objects on a gram scale which can be handled as ordinary chemical substances and implemented in several opto-electronic devices as well as biological ambient. Today, colloidal nanocrystals are successfully used as active media in lasers (Chan, et al., 2004; Klimov et al., 2000, 2007), LEDs (Anikeeva et al., 2009; Caruge et al., 2008), photovoltaic (Gur et al., 2005; Huynh et al., 2002; Kim et al., 2003), sensors (Oertel et al., 2005), biological labelling (Deka et al., 2009; Michalet et al., 2001 …