Electron-conducting quantum dot solids: novel materials based on colloidal semiconductor nanocrystals.
We review the optical and electrical properties of solids that are composed of semiconductor nanocrystals. Crystals, with dimensions in the nanometre range, of II-VI, IV-VI and III-V compound semiconductors, can be prepared by wet-chemical methods with a remarkable control of their size and shape, and surface chemistry. In the uncharged ground state, such nanocrystals are insulators. Electrons can be added, one by one, to the conduction orbitals, forming artificial atoms strongly confined in the nanocrystal. Semiconductor nanocrystals form the building blocks for larger architectures, which self-assemble due to van der Waals interactions. The electronic structure of the quantum dot solids prepared in such a way is determined by the orbital set of the nanocrystal building blocks and the electronic coupling between them. The opto-electronic properties are dramatically altered by electron injection into the orbitals. We discuss the optical and electrical properties of quantum dot solids in which the electron occupation of the orbitals is controlled by the electrochemical potential.
Vanmaekelbergh
Daniel
D
Condensed Matter and Interfaces, Debye Institute, University of Utrecht, Princetonplein 1, 3508 TA, Utrecht, The Netherlands. daniel@phys.uu.nl
Liljeroth
Peter
P
D003102:Colloids / Q000737:chemistry*; D003460:Crystallization; D004553:Electric Conductivity; D004583:Electrons; D036103:Nanotechnology / Q000379:methods; D045663:Quantum Dots; D011789:Quantum Theory; D012666:Semiconductors
D003102:Colloids