Direct Photopatterning of Quantum Dots via Thiol-yne Click Chemistry

Functional nanomaterials are revolutionizing electronic devices such as displays and photovoltaics, yet existing semiconductor manufacturing methods struggle to adapt to the unique properties of nanoparticles. In particular, quantum dots (QDs) display density-dependent properties such as tunable energy transfer, yet current preferred methods of producing QD patterns lack control over the density of QDs deposited in specific locations on a surface. Here, we present a photochemical method to generate QD patterns directly from solution onto a functionalized surface, which enables density control. The overall dose of light used in the pattern (visible or UV) determines the surface density of deposited QDs at different positions within the same pattern, enabling the fabrication of complex gradients. The method relies on thiol-yne click chemistry, which is used to bind aqueous-phase, alkyne-terminated InP/ZnS, CdSe/ZnS, and CdSe QDs onto glass and quartz surfaces, which are functionalized with one of two thiolating reagents. The additive, bottom-up nature of the method differs from previously developed subtractive techniques, and the ability to create gradients is unique among QD patterning approaches. Gradient fabrication relies on our use of a digital light projector, enabling control of irradiance, and therefore QD deposition, on a per-pixel basis within a projected image. As our approach relies on functional groups grafted onto the QDs, it is applicable to any nanoparticles capable of being functionalized. The work provides an exciting path for the incorporation of functional nanomaterials in electronic devices and enables the study and utilization of density-dependent properties.