Generalised Optical Printing of Photocurable Metal Chalcogenides

Abstract
Optical three-dimensional (3D) printing techniques have attracted tremendous attention owing to their applicability to mask-less additive manufacturing, which enables the cost-effective and straightforward creation of patterned architectures. However, despite their potential use as alternatives to traditional lithography, the printable materials obtained from these methods are strictly limited to photocurable resins, thereby restricting the functionality of the printed objects and their application areas. Herein, we report a generalised direct optical printing technique to obtain functional metal chalcogenides via digital light processing. We developed universally applicable photocurable chalcogenidometallate inks that could be directly used to create 2D patterns or micrometre-thick 2.5D architectures of various sizes and shapes. Our process is applicable to a diverse range of functional metal chalcogenides for compound semiconductors and 2D transition-metal dichalcogenides. We then demonstrated the feasibility of our technique by fabricating and evaluating a micro-scale thermoelectric generator bearing tens of patterned semiconductors. Our approach shows potential for simple and cost-effective architecturing of functional inorganic materials.

Patterning of materials is considered an essential prerequisite for the fabrication of high-resolution and high-performance devices. Various methods have been developed, yet conventional manufacturing processes often require multi-step processes or expensive lithography equipment.

A research team, affiliated with UNIST has recently unveiled a new patterning technique, which is as simple as the photo printing process. This breakthrough has been jointly led by Professor Jae Sung Son (Department of Materials Science and Engineering) and Professor Jiseok Lee (School of Energy and Chemical Engineering) from UNIST.

In this study, the research team reported a generalized direct optical printing technique to obtain functional metal chalcogenides via digital light processing (DLP). In doing so, the research team developed universally applicable photocurable chalcogenidometallate (ChaM)-based inks that could be directly used to create 2D patterns or micrometre-thick 2.5D architectures of various sizes and shapes.

Figure 1. Generalized optical printing of metal chalcogenide. (a) Schematic of the digital light processing (DLP)-based optical printing of chalcogenidometallate (ChaM)-based inks.

According to the research team, their process is applicable to a diverse range of functional metal chalcogenides for compound semiconductors and 2D transition-metal dichalcogenides. The research team also demonstrated the feasibility of our technique by fabricating and evaluating a micro-scale thermoelectric generator bearing tens of patterned semiconductors.

“We believe that our technology, in combination with high-resolution equipment, such as two-photon lithography, can realise the patterning of inorganic materials with excellent quality and resolution,” noted the research team “Our DLP-based optical printing technology presents an alternative approach to photolithography and can serve as a platform technology for the cost-effective, simple, and high-resolution direct architecturing of inorganic materials.”

Their findings have been published in the online version of Nature Communications on September 9, 2022. This study has been supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (MSIT).

Journal Reference
Seongheon Baek, Hyeong Woo Ban, Sanggyun Jeong, et al., “Generalised optical printing of photocurable metal chalcogenides,” Nat. Commun., (2022).