Boosting Photoconductivity by Increasing the Structural Complexity of Multivariate Covalent Organic Frameworks
Marta Gordo-Lozano1, Marcos Martínez-Fernández1, Rajendra Prasad Paitandi2
1Facultad de CC. Químicas, Universidad Complutense de Madrid, Avenida Complutense s/n, Madrid, 28040, Spain.
Small (Weinheim an Der Bergstrasse, Germany)
|November 20, 2024
Summary
Researchers developed novel pyrene-based Covalent Organic Frameworks (COFs) for organic semiconductors. Multivariate synthesis optimized photoconductivity by tuning acceptor content, achieving a high mobility of 7.9 × 10-5 cm2 V-1 s-1.
Area of Science:
- Materials Science
- Organic Electronics
- Semiconductor Physics
Background:
- Donor-Acceptor (D-A) heterojunctions are crucial for organic semiconductors.
- Developing novel materials with enhanced photoconductivity is essential for optoelectronics.
- Covalent Organic Frameworks (COFs) offer tunable properties for semiconductor applications.
Purpose of the Study:
- To synthesize pyrene-based Donor-Acceptor (D-A) Covalent Organic Frameworks (COFs) using multivariate synthesis.
- To investigate the impact of varying acceptor content on the structural and optoelectronic properties of COFs.
- To optimize the photoconductivity of these D-A COFs for potential use in organic electronics.
Main Methods:
- Multivariate synthesis of pyrene-based COFs with distinct acceptor units.
- Characterization using powder X-ray diffraction, N2 sorption, electron microscopy, and in silico calculations.
- Photoconductivity measurements to assess material performance.
Main Results:
- Multicomponent synthesis successfully modified COF properties, including bandgap, while maintaining crystallinity and porosity.
- Ordered D-A arrays were formed, showing promise for photoconductive applications.
- Photoconductivity exhibited a volcano-type correlation with acceptor content, peaking at 7.9 × 10-5 cm2 V-1 s-1 for NIP25%-COF.
Conclusions:
- Multivariate synthesis is an effective strategy for enhancing the photoconductivity of D-A COFs through "defect" engineering.
- The developed COFs demonstrate excellent photoconductive properties without compromising structural integrity.
- These materials represent promising candidates for next-generation organic semiconductors in optoelectronics.
Related Concept Videos
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.8K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.8K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.0K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.0K
02:42Valence Bond Theory
8.5K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.5K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.3K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.3K
01:18Aromatic Hydrocarbon Cations: Structural Overview
2.8K
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group...
Removing one hydrogen from the intervening CH2 group...
2.8K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
41.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
41.5K