Letter www.acsami.org
Growth of Large-Size SnS Thin Crystals Driven by Oriented Attachment and Applications to Gas Sensors and Photodetectors Jun Wang,†,‡,§ Gang Lian,*,†,‡,|| Zhenghao Xu,§ Chen Fu,⊥ Zhaojun Lin,⊥ Liyi Li,|| Qilong Wang,§ Deliang Cui,*,‡ and Ching-Ping Wong*,|| ‡
State Key Lab of Crystal Materials, §Key Lab for Special Functional Aggregated Materials of Education Ministry, School of Chemistry & Chemical Engineering, and ⊥School of Physics, Shandong University, Jinan 250100, P. R. China || School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States S Supporting Information *
ABSTRACT: Freestanding large-size SnS thin crystals are synthesized via two-dimensional oriented attachment (OA) growth of colloidal quantum dots (CQDs) in a novel highpressure solvothermal reaction. The SnS thin crystals present a uniform rectangular shape with a lateral size of 20−30 um and thickness of 1 × 104 cm−1) across the ultraviolet, visible, and near-infrared regions. These properties make it potentially applicable in photovoltaic devices, photodetectors, field-effect transistors and holographic recording devices.11 When used as the intrinsic semiconductor/absorber layer in solar cells, the theoretical maximum of power conversion efficiency is 24% predicted.12 More importantly, 2D atomic crystal of SnS bridges the band gap and carrier mobility discrepancy between graphene (zero band gap, high carrier mobility μ> 106 cm2 V s−1) and 2D transition-metal dichalcogenides (wide band gap Eg ≈ 2.0 eV, low carrier mobility μ ≈ 100 cm2 V s−1).13 Given © 2016 American Chemical Society
Received: February 5, 2016 Accepted: April 7, 2016 Published: April 7, 2016 9545
DOI: 10.1021/acsami.6b01485 ACS Appl. Mater. Interfaces 2016, 8, 9545−9551
Letter
ACS Applied Materials & Interfaces attachment of two or more adjacent nanocrystals. They share a common crystallographic orientation and fuse into a large crystal. In such a process, organic ligands play a crucial role in triggering the OA by capping nanoparticles surfaces selectively.17 Herein, a novel high-pressure solvothermal method was developed to prepare large-size SnS thin crystals via 2D OA growth of CQDs. The obtained uniform rectangular SnS crystals are 20−30 um in lateral size and
