Colloidal semiconductor nanocrystals have been attracting increasing technological interest for applications in lighting and ffat-panel display applications.[1–7] In particular, continuing improvements in synthetic methods have enabled the design of high-quality quantum dot (QD) structures with photoluminescence (PL) ranging across the visible spectrum, a PL full width at half maximum (FWHM) less than 30 nm, and a PL efficiency higher than 50%.[6–10] Several approaches including wet deposition techniques such as spin-coating,[1–6] drop-casting,[11] electrodeposition,[12] and Langmuir–Schafer methods [13, 14] have been used to fabricate QD thin films. Device structures incorporating QDs have also been fabricated using some of these approaches. Hybrid organic–inorganic light-emitting diodes (LEDs) have been fabricated using host–guest systems comprising a polymer doped with nanocrystals.[2] In another approach, trilayer hybrid polymer–QD LEDs have been fabricated by sandwiching several monolayers of CdSe/ZnS nanocrystals between a hole-conducting polymer and an electron-conducting oxadiazole derivative.[4] In this case, all the layers have been deposited by spin-coating from very dissimilar solvents, for example, CdSe/ZnS QDs have been deposited from aqueous solution, whereas polymers have been deposited from organic solvents. High-efficiency electroluminescent devices have been reported by Coe-Sullivan et al. using the phase-separation technique.[1, 5] These authors have achieved the phase separation of small organic molecules and aliphatically capped QDs during the spin-coating of blends of such materials. However, a major drawback of all these device structures is that they are limited by the chemical properties of the materials and the deposition techniques employed to fabricate these films. In practical terms, this sets stringent restrictions on the organic materials that can be used to fabricate the hole-transporting and hole-injection layers (HTL and HIL, respectively), which are critical for the optimization of the device emission.[1, 4, 6] Unlike organic small molecules, it is not possible to deposit QDs by thermal evaporation owing to their high molecular weight. Consequently, the separation of the QD active layer from organic transport layers and the fabrication of multilayered organic–inorganic structures still remains a significant challenge. The absence of an appropriate QD deposition technique has strongly limited the implementation of hybrid LEDs in technologically relevant heterojunction devices. This technology is expected to yield significant improvements in the efficiency and lifetime of the devices. Microcontact printing (mCP) offers a promising alternative to the above-described QD wet deposition methods. This approach has already been used for the deposition of uniform closepacked monolayer and bilayer arrays of alkanethiol-capped Au nanoparticles.[14] In another example, mCP has been used for the deposition of (CdxZn1 À xSe) CdyZn1 À yS core/shell nanocrystals on 4, 40-N, N0-diphenylcarbazole (CBP) for the fabrication of green LEDs.[7] Moreover, a combination of mCP and covalent linkage has been used for the fabrication of a selectively patterned monolayer assembly of Co nanoparticles.[15] In the standard mCP technique, a poly (dimethylsiloxane)(PDMS) stamp is inked with the relevant material, which is then transferred onto a solid substrate by achieving conformal contact of the stamp pad and the substrate.[16] PDMS is an elastomer that is able to make conformal contact with surfaces over relatively large areas, thus enabling the patterning of micrometer-sized features. One of the most …