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De R, Maity M, Joseph A, Gupta SP, Nailwal Y, Namboothiry MAG, Pal SK. High Electrical Conductivity and Hole Transport in an Insightfully Engineered Columnar Liquid Crystal for Solution-Processable Nanoelectronics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308983. [PMID: 38332439 DOI: 10.1002/smll.202308983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/23/2023] [Indexed: 02/10/2024]
Abstract
Discotic liquid crystals (DLCs) are widely acknowledged as a class of organic semiconductors that can harmonize charge carrier mobility and device processability through supramolecular self-assembly. In spite of circumventing such a major challenge in fabricating low-cost charge transport layers, DLC-based hole transport layers (HTLs) have remained elusive in modern organo-electronics. In this work, a minimalistic design strategy is envisioned to effectuate a cyanovinylene-integrated pyrene-based discotic liquid crystal (PY-DLC) with a room-temperature columnar hexagonal mesophase and narrow bandgap for efficient semiconducting behavior. Adequately combined photophysical, electrochemical, and theoretical studies investigate the structure-property relations, logically correlating them with efficient hole transport. With a low reorganization energy of 0.2 eV, PY-DLC exhibits superior charge extraction ability from the contact electrodes at low values of applied voltage, achieving an electrical conductivity of 3.22 × 10-4 S m-1, the highest reported value for any pristine DLC film in a vertical charge transport device. The columnar self-assembly, in conjunction with solution-processable self-healed films, results in commendably elevated values of hole mobility (≈10-3 cm2 V-1s-1). This study provides an unprecedented constructive outlook toward the development of DLC semiconductors as practical HTLs in organic electronics.
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Affiliation(s)
- Ritobrata De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Madhusudan Maity
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Alvin Joseph
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | | | - Yogendra Nailwal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Manoj A G Namboothiry
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
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Chen L, Cai J, Zhen Y, Ou C, Ding X, Lin J. Ultraviolet Organic Laser from Rhombus Microcrystal: Benefits of Single-Molecule Emission from Twisted Structure. J Phys Chem Lett 2024; 15:1028-1033. [PMID: 38253018 DOI: 10.1021/acs.jpclett.3c03106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Light-emitting molecular crystals with efficient emission behavior are crucial for fabricating low-threshold ultraviolet organic lasers. Herein, we demonstrated a rhombus microcrystal from a fluorene-based conjugated molecule (CL-1) with robust emission behavior for an ultraviolet organic laser. Due to the synergistic effect of twisted intramolecular conformation and weak π-interaction, the CL-1 single crystal showed an extremely high photoluminescence quantum yield (PLQY) of ∼82%, due to their single-molecule excitonic behavior. Considering the diverse noncovalent interactions, CL-1 molecules easily self-assembled into the rhombus microcrystals. Finally, a low-threshold ultraviolet organic laser was fabricated with a sharp emission at 379 nm, attributed to the 0-1 vibration band of a single CL-1 molecule, also further confirming the single twisted-molecule emission in crystal states. Precisely controlling the intramolecular twisted structure and intermolecular interaction of organic conjugated molecules is a precondition to obtain robust ultraviolet emission for optoelectronic applications.
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Affiliation(s)
- Lin Chen
- School of Environment and Safety Engineering, Nanjing Polytechnic Institute, Nanjing 210048, China
- Centre for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Jiangli Cai
- Centre for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Yingying Zhen
- Centre for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Changjin Ou
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Xuehua Ding
- Centre for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Jinyi Lin
- Centre for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
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