Non‐conjugated pendant electroactive polymers (NCPEPs) are an emerging class of polymers that offer the potential of combining the desirable optoelectronic properties of conjugated polymers with the superior synthetic methodologies and stability of traditional non‐conjugated polymers. Despite an increasing number of studies focused on NCPEPs, particularly on understanding fundamental structure‐property relationships, no attempts have been made to provide an overview on established relationships to date. This review showcases selected reports on NCPEP homopolymers and copolymers that demonstrate how optical, electronic, and physical properties of the polymers are affected by tuning of key structural variables such as the chemical structure of the polymer backbone, molecular weight, tacticity, spacer length, the nature of the pendant group, and in the case of copolymers the ratios between different comonomers and between individual polymer blocks. Correlation of structural features with improved
This content will become publicly available on July 31, 2024
Copolymers for electronic, optical, and sensing applications with engineered physical properties
Electronic and optoelectronic devices often require multifunctional properties combined with conductivity that are not achieved from a single species of molecules. The capability to tune chain length, shape, and physicochemical characteristics of conductive copolymers provides substantial benefits for a wide range of scientific areas that require unique and engineered optical, electrical, or optoelectronic properties. Although efforts have been made to develop synthetic routes to realize such promising copolymers, an understanding of the process–structure–property relationship of the synthesis methods needs to be further enhanced. In addition, since traditional methods are often limited to achieving pinhole-free, large-area coverage, and conformal coating of copolymer films with thickness controllability, unconventional synthetic strategies to address these issues need to be established. This Perspective article intends to enhance knowledge on the process–structure–property relationship of functional copolymers by providing the definition of copolymers, polymerization mechanisms, and a comparison of traditional and emerging synthetic methods with reaction parameters and tuned physical properties. In parallel, practical applications featuring the desired copolymers in electronic, optical, and sensing devices are showcased. Last, a pathway toward further advancement of unique copolymers for next-generation device applications is discussed.
more »
« less
- Award ID(s):
- 2207302
- NSF-PAR ID:
- 10451165
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 123
- Issue:
- 5
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract π ‐stacking and enhanced charge carrier mobility serve as the primary figures of merit in evaluating impact on NCPEP properties. While this review is not intended to serve as a comprehensive summary of all reports on tuning of structural parameters in NCPEPs, it highlights relevant established structure‐property relationships that can serve as a guideline for more targeted design of novel NCPEPs in the future. -
Conjugated copolymers containing electron donor and acceptor units in their main chain have emerged as promising materials for organic electronic devices due to their tunable optoelectronic properties. Herein, we describe the use of direct arylation polymerization to create a series of fully π-conjugated copolymers containing the highly tailorable purine scaffold as a key design element. To create efficient coupling sites, dihalopurines are flanked by alkylthiophenes to create a monomer that is readily copolymerized with a variety of conjugated comonomers, ranging from electron-donating 3,4-dihydro-2 H -thieno[3,4- b ][1,4]dioxepine to electron-accepting 4,7-bis(5-bromo-3-hexylthiophen-2-yl)benzo[ c ][1,2,5]thiadiazole. The comonomer choice and electronic nature of the purine scaffold allow the photophysical properties of the purine-containing copolymers to be widely varied, with optical bandgaps ranging from 1.96–2.46 eV, and photoluminescent quantum yields as high as ϕ = 0.61. Frontier orbital energy levels determined for the various copolymers using density functional theory tight binding calculations track with experimental results, and the geometric structures of the alkylthiophene-flanked purine monomer and its copolymer are found to be nearly planar. The utility of direct arylation polymerization and intrinsic tailorability of the purine scaffold highlight the potential of these fully conjugated polymers to establish structure–property relationships based on connectivity pattern and comonomer type, which may broadly inform efforts to advance purine-containing conjugated copolymers for various applications.more » « less
-
Two-dimensional (2D) organic–inorganic hybrid halide perovskites exhibit unique properties, such as long charge carrier lifetimes, high photoluminescence quantum efficiencies, and great tolerance to defects. Over the last several decades tremendous progress has occurred in the development of 2D layered halide perovskite semiconductor materials and devices. Chemical functionalization of 2D halide perovskites is an effective approach for tuning their electronic properties. A large amount of effort has been made in compositional engineering of the cations and anions in the perovskite lattice. However, few efforts have incorporated rationally designed semiconducting organic moieties into these systems to alter the overall chemical and optoelectronic properties of 2D perovskites. In fact, incorporation of large conjugated organic groups in the spatially confined inorganic perovskite matrix was found to be challenging, and this synthetic challenge hinders a deeper understanding of the materials’ structure–property relationships. Recently, exciting progress has been made regarding the molecular design, optical characterization, and device fabrication of novel 2D halide perovskite materials that incorporate functional organic semiconducting building blocks. In this article, we provide a timely review regarding this recent progress. Moreover, we discuss successes and current challenges regarding the synthesis, characterization, and device applications of such hybrid materials and provide a perspective on the true future promise of these advanced nanomaterials.more » « less
-
The versatility of early transition metal chalcogenide nanomaterials, including chalcogenide perovskites, has attracted enormous attention for a variety of applications, such as photovoltaics, photocatalysis, and optoelectronic devices. These nanomaterials exhibit unique electronic and optical properties, allowing for a broad range of applications, depending on their chemical composition and crystal structure. However, solution-phase synthesis of early transition metal chalcogenide nanocrystals is challenging due, in part, to their high crystallization energy and oxophilicity. In this feature article, we explore various synthetic routes reported for inorganic ternary and binary sulfide and selenide nanomaterials that include transition metals from groups 3, 4, and 5. By systematically comparing different synthetic approaches, we identify trends and insights into the chemistry of these chalcogenide nanomaterials.more » « less
-
null (Ed.)Gallium oxide (Ga 2 O 3 ) and its most stable modification, monoclinic β-Ga 2 O 3 , is emerging as a primary material for power electronic devices, gas sensors and optical devices due to a high breakdown voltage, large bandgap, and optical transparency combined with electrical conductivity. Growth of β-Ga 2 O 3 is challenging and most methods require very high temperatures. Nanowires of β-Ga 2 O 3 have been investigated extensively as they might be advantageous for devices such as nanowire field effect transistors, and gas sensors benefiting from a large surface to volume ratio, among others. Here, we report a synthesis approach using a sulfide precursor (Ga 2 S 3 ), which requires relatively low substrate temperatures and short growth times to produce high-quality single crystalline β-Ga 2 O 3 nanowires in high yields. Even though Au- or Ag-rich nanoparticles are invariably observed at the nanowire tips, they merely serve as nucleation seeds while the nanowire growth proceeds via supply and local oxidation of gallium at the substrate interface. Absorption and cathodoluminescence spectroscopy on individual nanowires confirms a wide bandgap of 4.63 eV and strong luminescence with a maximum ∼2.7 eV. Determining the growth process, morphology, composition and optoelectronic properties on the single nanowire level is key to further application of the β-Ga 2 O 3 nanowires in electronic devices.more » « less
