Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
In-depth Carrier Transport in a Barrier Variable Iron-oxide and Vertically Aligned Reduced-Graphene Oxide Composite.
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.ORCID iD: 0000-0002-3956-444X
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Division of Surface and Corrosion Science, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden.ORCID iD: 0000-0001-6877-9282
Nanostructure Physics, KTH Royal Institute of Technology, 114 19 Stockholm, Sweden; Intermodulation Products AB, 823 93 Segersta, Sweden.
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.ORCID iD: 0000-0003-1785-7177
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

A key requirement for semiconductors operating in light harvesting devices, is to efficiently convert the absorbed photons to electronic excitations while accommodating low loss pathways for the photogenerated carrier’s transport. The quality of this process corresponds to different relaxation phenomena, yet primarily it corresponds to minimized thermalization of photoexcited carriers and maximum transfer of electron-hole pairs in the bulk of semiconductor through carrier-carrier scattering process. However, several semiconductors, while providing a suitable platform for light harvesting applications, pose intrinsic low carrier diffusion length of photoexcited carriers. Here we report a system based on a vertical network of reduced graphene oxide (rGO) embedded in a thin-film structure of iron oxide semiconductor, intended to employ carrier-carrier scattering properties of rGO to increase the photoexcited carrier transfer in the bulk of the semiconductor. Using intermodulation conductive force microscopy, we locally monitored the fluctuation of current output, which is the prime indication of the prevailing carrier-carrier scattering mechanism in the system. We reveal the fundamental properties of vertical rGO and semiconductor junction in light harvesting systems that enable the design of new promising materials with broad-band optical applications. 

National Category
Nano Technology
Research subject
Experimental Physics
Identifiers
URN: urn:nbn:se:ltu:diva-86689OAI: oai:DiVA.org:ltu-86689DiVA, id: diva2:1585423
Funder
Luleå University of TechnologyThe Kempe FoundationsEU, Horizon 2020, 654002Wallenberg FoundationsVinnova
Note

Forskningsfinansiär: Swedish Foundations Consolidator Fellowship

Available from: 2021-08-17 Created: 2021-08-17 Last updated: 2021-10-15
In thesis
1. Alternative Energy Harvesting and Conversion Systems Based on Nanostructured Heterostructures
Open this publication in new window or tab >>Alternative Energy Harvesting and Conversion Systems Based on Nanostructured Heterostructures
2021 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Conversion and storage of the solar radiation into applicable forms of energy, using ubiquitous materials is of central importance that quests several disciplinary fields in both applied technology and fundamental science. Harnessing the solar energy received by the earth has the potential to replace the current sources of energy and it is imperative for sustainable development. 

Since the early development of modern photovoltaics (PVs), based on silicon wafers, a rational step was the substantial development of the new generation PV technologies that can provide lower-cost and higher efficiency than their predecessors. Deliberate solutions involved employing different semiconducting materials that are indispensable, non-toxic and compatible with large-scale fabricating technologies.  

Exploiting metal oxide (MOx) semiconductors, a broad class of non-toxic, cheap and abundant materials, is already promoted as a key component for high-performance optoelectronic devices and can be an ideal solution for inexpensive harnessing of sustainable energy resources like Sun light. The favorable band gap and high absorption cross-section of some MOx semiconductors permit utilizing different spectral region of the solar spectrum. However, at this present, the implication of MOx in high-throughput optoelectronic devices remained on the low side. Some of the main drawbacks that attain to poor performance of the MOx are associated with their poor intrinsic carrier mobility especially in p-type light absorbers and insufficient visible light absorption notably in n-type semiconductors.   

The main aim of this thesis is to further contribute to the development and exploitation of this class of materials with the main focus on their role in optoelectronic devices and energy storage systems. 

The content of this thesis considers two main aspect of the research. 

Substantially, this work analyses the vital role of the interface engineering using nanostructured MOx, where we exploit unique phenomena such as intense electric field confinement in 1dimensional (1D) structures resulting in ample light trapping in the fabricated heterojunctions. Unfortunately, this fact comes at the cost of introducing space charge region (SCR) limits in the fabricated devices attaining for poor derived currents. 

Here I would probably spend couple of words for introducing the Co3O4 NR as the basis for p-n inverted nanorod junction…

Plasmonic metal nanoparticles (NPs) were conventionally used to extend the spectral response of the wide-bandgap semiconductors. Within the scheme of this thesis, we employ the silver plasmonic NPs in a 1D light harvesting structure of zinc oxide (ZnO), where we mediate hot-carrier collection of the charges via controlled illuminations. 

Even further, we provide a comprehensive analysis on the hot-carrier redistribution mechanisms of the plasmonic NPs to semiconductor, providing direct experimental proof using transient pump-probe spectroscopy and time-resolved photoluminescence analysis. Our work resulted in a distinct understanding of the radiative and non-radiative carrier transfer between the active constituents of the system, which have not been corroborated previously.

In a parallel approach, the research activities in this work, take a few steps ahead and investigates the issues related to the disparities in the PV plants. A common prerequisite after conversion of the solar light using PV devices is the electrochemical storage of the energy where it can answer the needs for far-reaching energy requirements. Fostered by the intrinsic capacitance characteristic of the MOx, we interplay the role of the interfacial engineering in Co3O4 porous films and investigate the effect of their lateral architecture on Li+ ion adsorption and desorption properties.

Finally, our findings resulted in the fabrication of a hybrid device with dual functionality as an all-oxide PV system that can directly store the converted Sunlight as in a supercapacitor device. The prospect of this device can provide the over-potential required for direct storage of the converted solar energy into larger high storage systems.

In summary, the results presented in this thesis highlights the potential of the MOx semiconductors for photovoltaic and storage applications. We identify the various step-forward routes, which can provide the possibility of large-scale deployment of this novel class of materials.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2021
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
light harvesting, solar supercapacitors, energy conversion, Photovoltaic, energy storage, metal oxide semiconductors
National Category
Nano Technology
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-86691 (URN)978-91-7790-906-4 (ISBN)978-91-7790-907-1 (ISBN)
Public defence
2021-10-05, E632, Luleå, 13:00 (English)
Opponent
Supervisors
Available from: 2021-08-17 Created: 2021-08-17 Last updated: 2021-10-15Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records

Gilzad Kohan, MojtabaDobryden, IlliaConcina, IsabellaVomiero, Alberto

Search in DiVA

By author/editor
Gilzad Kohan, MojtabaDobryden, IlliaConcina, IsabellaVomiero, Alberto
By organisation
Material Science
Nano Technology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 132 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf