Projects / Programmes
Charge Transport Properties of Two-Dimensional Conjugated Polymers
| Code |
Science |
Field |
Subfield |
| 1.02.00 |
Natural sciences and mathematics |
Physics |
|
| Code |
Science |
Field |
| 1.03 |
Natural Sciences |
Physical sciences |
Organic semiconductors, two-dimensional conjugated polymers, charge transport, time-of-flight photoconductivity, organic-thin-film transistor, scanning near-field optical microscopy
Data for the last 5 years (citations for the last 10 years) on
April 18, 2024;
A3 for period
2018-2022
Data for ARIS tenders (
04.04.2019 – Programme tender,
archive
)
| Database |
Linked records |
Citations |
Pure citations |
Average pure citations |
| WoS |
11 |
231 |
226 |
20.55 |
| Scopus |
12 |
244 |
238 |
19.83 |
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
54880 |
PhD Nadiia Pastukhova |
Physics |
Head |
2021 - 2024 |
24 |
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
1540 |
University of Nova Gorica |
Nova Gorica |
5920884000 |
14,060 |
Abstract
Charge transport in organic semiconductors, in particular in polymers, is usually incoherent. This originates from weak intermolecular interactions, resulting in poor crystallinity and the absence of long-range order. Defects such as displaced molecules, unfavorably aligned polymer chains, grain boundaries, and other deviations from a crystalline structure, introduce localized unoccupied electronic states in the energy gap. These states are known as traps. Once a free charge carrier occupies these states, it becomes localized. Furthermore, the carrier needs extra energy to be exited back to the conduction level. Charge carrier trapping continuously interrupts charge carrier transport in organic semiconductors. In polymers, the charge transport from end to end of the polymer chain is fast due to pi-conjugation extending from one end of the polymer chain to another. However, the percolation of charge carriers between different polymer chains presents the main bottleneck for carrier mobility in thin-films consisting of linear polymers. The percolation of charges is obstructed by defects resulting from poor alignment of polymer chains. To overcome the problems with the alignment of linear chains, this project will investigate the charge transport properties of polymers with pi-conjugation extending into two-dimensions. 2D conjugated polymers (2DCPs) are a new class of organic semiconductors that have been made available in recent years by the development of specialized synthesis techniques that favor polymerization into 2-dimensions to form atomically thin 2D sheets. It is expected that 2DCPs with pi-conjugation extended into two-dimensions will form a well-aligned 2D sheet network, thus the formation of defect states at the intersection of two polymers will be avoided. Another key advantage of the increased dimensionality is the availability of the multiple strings that can offer more intramolecular pathways for charge carriers. The 2DCPs thin films used within this project will be prepared by surfactant-monolayer-assisted interfacial synthesis (SMAIS) which was introduced to prepare large-area thin films of 2DCPs . SMAIS gives films with the best long-range ordered structures and allows the thickness to be tailored from monolayer up to 200 nm. From a set of polyimides and polyimines 2DCPs, this project will identify chemical structures with potential to achieve high photoconductivity by employing time-of-flight photoconductivity (TOFP), and detailed morphology and structure analysis. Thermal annealing will be employed to improve the polymer stacking, and the effect of annealing will be investigated. To distinguish the charge transport mechanism between linear and 2D polymers, the location-specific techniques such as conductive atomic force microscopy (CAFM) and Kelvin probe force microscopy (KPFM) will be used. As they provide an immediate correlation between the morphology of a material with the local conductivity and surface potential. This will allow the identification of defect states and clarify the charge transport between individual 2D polymer sheets. Additionally, TOFP measurements will be done using a purposely adapted scanning near-field optical microscopy (SNOM) that exploits evanescent fields to focus the laser light to a diameter smaller than the light wavelength. This will allow performing TOFP by excitation of charge carriers in the individual 2D sheet, and further, elucidate the role of 2D sheet interconnectivity for charge transport in 2DCPs.
