Novel assemblies and self-assembly architectures are currently of great interest for nanochemistry and chemical nanotechnology. The assemblies are generally considered as bottom-up alternative to top-down methods (i.e., nanolithography, e-beam epitaxy, and others).Stable, water-soluble, strongly light-emitting thiol-capped CdTe nanocrystals (NCs) [1,2] are promising materials for nanotechnological applications such as bioimaging, [3,4] labeling [5][6][7][8] and coding, [9] light-emitting diodes, [10][11][12][13] nanophotonic devices, [14,15] and energy scavengers. [16] In particular, lightemitting diodes (LEDs) based on thiol-capped NCs are the only known devices that are assembled by utilizing environmentally friendly layer-by-layer (LbL) technology under ambient conditions and show electroluminescence that is visible to the naked eye. This is stable for hours in air with output parameters as high as 0.51% external quantum efficiency, 0.8 lm W À1, and 0.4 cd A À1 luminous efficiency.[13]The aqueous approach to the synthesis of thiol-capped NCs is relatively low-toxic, routinely yields NCs with photoluminescence (PL) quantum efficiencies (QE) of 60% without postpreparative treatment, [17] can be easily scaled up, and is applicable to a variety of II-VI semiconductor NCs (CdTe, [2] ZnSe, [18] CdSe, [19] and HgTe [20] ) with optical activities covering the spectral region from the UV through visible into the near IR. The PL QE, the size distribution, the stability, and the solvent compatibility of these NCs may additionally be improved by post-preparative size-selective precipitation, [1] by photochemical treatment, [18,21] or by capping-agent exchange. [22,23] One of the main tasks of bottom-up nanotechnology is the controllable manipulation and addressing of nano-objects (e.g., nanoparticles, functional molecules) to assure their desired positioning and efficient performance in future devices. Therefore, the development and improvement of assembly approaches is at the focus of current research activities. NCs stabilized with short-chain thiols possessing terminal groups such as amino, carboxy, hydroxy, and others exhibit both specific functionalities and charge, allowing assembly into 1D structures on molecular templates, [24] covalent linkage to surfaces yielding stable 2D layers, [25] and electrostatic assembly into 2D-3D LbL structures. [26] Another attractive feature of this type NCs is their ability to self-assemble, that is, to create superstructures without additional templates or functional molecules. It has been shown that thioglycolic-acid-capped CdTe NCs may self-assemble, yielding brightly emitting and stable nanowires as a result of a gentle destabilization of the colloidal solution by partial removal of the capping agent [27] or by the addition of a specific buffer. [28] CdTe NCs capped with 2-(dimethylamino)ethanethiol may form 2D sheets that are free floating in solution and possess a certain physical integrity, showing remarkable stability during gentle stirring and drying. [29] Very small molecu...

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