TY - JOUR
T1 - Designing High-Performance CdSe Nanocrystal Thin-Film Transistors Based on Solution Process of Simultaneous Ligand Exchange, Trap Passivation, and Doping
AU - Lee, Woo Seok
AU - Kang, Yoon Gu
AU - Woo, Ho Kun
AU - Ahn, Junhyuk
AU - Kim, Haneun
AU - Kim, Donggyu
AU - Jeon, Sanghyun
AU - Han, Myung Joon
AU - Choi, Ji Hyuk
AU - Oh, Soong Ju
N1 - Funding Information:
The authors thank Dr. M.-C. Jung (Department of Physics, Korea Advanced Institute of Science and Technology) for his thorough discussions. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2019R1C1C1003319), and Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2018M3D1A1059001). This research was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1A2B2005204), the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2018R1C1B6002958), and Korea University Future Research Grant.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/11/26
Y1 - 2019/11/26
N2 - We report a simple, solution-based, and postsynthetic process for simultaneous ligand exchange, surface passivation, and doping of CdSe nanocrystals (NCs) for the design of high-performance field-effect transistors (FETs). Strong electronic coupling, effective surface trap passivation, and n-type doping of the NCs could be achieved by simply immersing the as-synthesized CdSe NC thin films into InX3 (X = Cl, Br, I) solution. The optical, chemical, and structural properties of these CdSe NC thin films were analyzed, revealing successful ligand exchange and In doping. It is demonstrated that the doping level could be precisely controlled from lightly doped films to degenerately doped films by adjusting the type and concentration of halogen used in the ligand exchange solution. Ultraviolet photoelectron spectroscopy, first-principles calculation, and temperature-dependent electrical characterization of the InX3-treated CdSe NC FETs were performed to fundamentally understand their electronic structure and charge transport behavior. Combinational studies show that halides, as well as In, significantly affect the charge transport behavior in terms of halide-induced trap states as well as both tunneling and hopping transport mechanisms. It is demonstrated that Cl induces strong electronic coupling, effective trap passivation, and moderate In doping, resulting in optimized FETs with a mobility of over 10 cm2 V-1 s-1, ION/IOFF of over 107, and low activation energy of around 1 meV or even band-like transport behavior. This work provides a novel technological strategy and fundamental information on nanoscience for the design of cost-efficient, high-performance NC-based electronic, and optoelectronic devices.
AB - We report a simple, solution-based, and postsynthetic process for simultaneous ligand exchange, surface passivation, and doping of CdSe nanocrystals (NCs) for the design of high-performance field-effect transistors (FETs). Strong electronic coupling, effective surface trap passivation, and n-type doping of the NCs could be achieved by simply immersing the as-synthesized CdSe NC thin films into InX3 (X = Cl, Br, I) solution. The optical, chemical, and structural properties of these CdSe NC thin films were analyzed, revealing successful ligand exchange and In doping. It is demonstrated that the doping level could be precisely controlled from lightly doped films to degenerately doped films by adjusting the type and concentration of halogen used in the ligand exchange solution. Ultraviolet photoelectron spectroscopy, first-principles calculation, and temperature-dependent electrical characterization of the InX3-treated CdSe NC FETs were performed to fundamentally understand their electronic structure and charge transport behavior. Combinational studies show that halides, as well as In, significantly affect the charge transport behavior in terms of halide-induced trap states as well as both tunneling and hopping transport mechanisms. It is demonstrated that Cl induces strong electronic coupling, effective trap passivation, and moderate In doping, resulting in optimized FETs with a mobility of over 10 cm2 V-1 s-1, ION/IOFF of over 107, and low activation energy of around 1 meV or even band-like transport behavior. This work provides a novel technological strategy and fundamental information on nanoscience for the design of cost-efficient, high-performance NC-based electronic, and optoelectronic devices.
UR - http://www.scopus.com/inward/record.url?scp=85074877637&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.9b02965
DO - 10.1021/acs.chemmater.9b02965
M3 - Article
AN - SCOPUS:85074877637
VL - 31
SP - 9389
EP - 9399
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 22
ER -