Letter pubs.acs.org/NanoLett
Solution Processable Colloidal Nanoplates as Building Blocks for High-Performance Electronic Thin Films on Flexible Substrates Zhaoyang Lin,† Yu Chen,‡ Anxiang Yin,† Qiyuan He,† Xiaoqing Huang,‡ Yuxi Xu,† Yuan Liu,‡ Xing Zhong,† Yu Huang,*,‡,§ and Xiangfeng Duan*,†,§ †
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, United States § California NanoSystems Institute, University of California, Los Angeles, California 90095, United States ‡
S Supporting Information *
ABSTRACT: Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for lowtemperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane−plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6−15 nm) and lateral dimension (0.5−3 μm) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm2·V−1·s−1, approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics. KEYWORDS: Solution process, 2D materials, nanoplates, flexible electronics, thin films
P
natural abundance of indium and the brittle nature of the ITO film pose a potential challenge for its application in future flexible devices. Additionally, ITO shows poor transparency in near-infrared (NIR) region due to the free carrier absorption, and thus unsuitable for infrared imaging, sensing, emission devices, or NIR-sensitive solar cells.9−12 On the other hand, it has been recently shown that CVD-grown Bi2Se3 thin films can function as an excellent infrared transparent conductor.6,8 Bi2Se3 is a layered narrow-bandgap semiconductor and also a typical topological insulator with metallic surface state.13,14 Theoretical and experimental studies have revealed that the conducting surface states in Bi2Se3 are concentrated within a few quintuple layer thickness (
Solution Processable Colloidal Nanoplates as Building Blocks for High-Performance Electronic Thin Films on Flexible Substrates Zhaoyang Lin,† Yu Chen,‡ Anxiang Yin,† Qiyuan He,† Xiaoqing Huang,‡ Yuxi Xu,† Yuan Liu,‡ Xing Zhong,† Yu Huang,*,‡,§ and Xiangfeng Duan*,†,§ †
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, United States § California NanoSystems Institute, University of California, Los Angeles, California 90095, United States ‡
S Supporting Information *
ABSTRACT: Low-temperature solution-processed electronic materials on plastic substrates are of considerable interest for flexible electronics. Solution dispersible inorganic nanostructures (e.g., zero-dimensional (0D) quantum dots or one-dimensional (1D) nanowires) have emerged as interesting ink materials for lowtemperature solution processing of electronic thin films on flexible substrates, but usually with limited performance due to the large number of grain boundaries (0D) or incomplete surface coverage (1D). Here, we report two-dimensional (2D) colloidal nanoplates of layered materials as a new ink material for solution assembly of high-performance electronic thin films. The 2D colloidal nanoplates exhibit few dangling bonds and represent an ideal geometry for the assembly of highly uniform continuous thin films with greatly reduced grain boundaries dictated by large-area conformal plane−plane contact with atomically flat/clean interfaces. It can therefore promise efficient charge transport across neighboring nanoplates and throughout the entire thin film to enable unprecedented electronic performance. We show that Bi2Se3 and Bi2Te3 nanoplates can be synthesized with well-controlled thickness (6−15 nm) and lateral dimension (0.5−3 μm) and can be used for the assembly of highly uniform continuous thin films with a full surface coverage and an excellent room temperature carrier mobility >100 cm2·V−1·s−1, approaching that of chemical vapor deposition grown materials. Our study demonstrates a general strategy to using 2D nanoplates as a unique building block for the construction of high-performance electronic thin films on plastic substrates for future flexible electronics and optoelectronics. KEYWORDS: Solution process, 2D materials, nanoplates, flexible electronics, thin films
P
natural abundance of indium and the brittle nature of the ITO film pose a potential challenge for its application in future flexible devices. Additionally, ITO shows poor transparency in near-infrared (NIR) region due to the free carrier absorption, and thus unsuitable for infrared imaging, sensing, emission devices, or NIR-sensitive solar cells.9−12 On the other hand, it has been recently shown that CVD-grown Bi2Se3 thin films can function as an excellent infrared transparent conductor.6,8 Bi2Se3 is a layered narrow-bandgap semiconductor and also a typical topological insulator with metallic surface state.13,14 Theoretical and experimental studies have revealed that the conducting surface states in Bi2Se3 are concentrated within a few quintuple layer thickness (
