Direct Optical Patterning of nanomaterials
To fully exploit various functionalities of colloidal inorganic nanocrystals, it is important to selectively deposit the nanocrystal arrays onto the desired locations of thin-film devices or integrated (opto)electronic circuitry by using precise material-adapted patterning methods.
Direct Optical Lithography of Functional Inorganic Nanomaterials (DOLFIN) is an alternative direct (i.e., photoresist-free) optical patterning method for colloidal inorganic nanocrystals [Talapin et al. Science 2017, 357, 385]. DOLFIN can overcome the limitations of traditional photolithography for solution processing such as the use of photoresists and nonuniform pattern profiles, however, its application to light-emissive nanocrystals requires advanced patterning methods that do not harm the optical and electrical characteristics of the nanocrystals. Our group works on the development of a next-generation DOLFIN method for light-emissive nanocrystals that can be practically adopted by industry.
 H. Cho et al., Advanced Materials 2020, 32(46), 2003805
3D-printed nanocrystal optoelectronics
Considering the emergence of wearable electronics that requires high-density 3D integration of different functional components in arbitrary forms, the patterning method should evolve from conventional methods (i.e., traditional photolithography and 2D printing) to more advanced methods that simultaneously feature high resolution (ideally, sub-µm), high throughput, uniform pattern profile, and 3D patternability.
Our group also strives for "material/device process innovation" based on 3D patterning of semiconducting nanomaterials; we will develop a source technology that provides 3D-printable nanomaterials and enables on-demand, on-site, rapid fabrication of optoelectronic devices, sensors, or integrated smart devices.