{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/358203"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/358203","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Developing next generation, non-toxic, inorganic materials for photovoltaics and thin-film transistors","abstract":"The focus of this thesis is on developing two next-generation inorganic materials for thin-film device applications, namely photovoltaics and thin-film transistors. Both of these device applications are crucial in today’s technology-based society with photovoltaics enabling sustainable generation of electricity whilst advancements in thin-film transistors allow for development of low-power, efficient electronic devices. BiOI, a non-toxic, perovskite-inspired material is investigated for photovoltaics (PVs) whilst Cu<sub>2</sub>O, with a reasonably high predicted hole mobility is developed for *p*-type thin-film transistors (TFTs). These novel materials are fabricated with scalable processing techniques which enable lower manufacturing costs and improve energy efficiency. In the first results chapter, the suitability of non-toxic BiOI as a photovoltaic material is investigated. Dense BiOI films grown by thermal chemical vapour deposition (CVD) incorporated into an all-inorganic ITO/NiO<sub>*x*</sub>/BiOI/ZnO/Al stack demonstrate high external quantum efficiencies (80% at 450 nm wavelength). However, the 1.9 eV band gap of BiOI is not matched to terrestrial solar spectra; the PVs achieve 1.8% power conversion efficiency. Owing to improved spectral matching with indoor light spectra, BiOI devices improve in efficiency to 4.37% under 1000 lux white light emitting diode indoor illumination, and millimetre-area BiOI devices are sufficient to power novel carbon nanotube inverters. The factor limiting further efficiency gains is downwards band-bending at the BiOI/NiO<sub>*x*</sub> interface owing to NiO<sub>*x*</sub> having a lower work function. In the second chapter, MoS<sub>2</sub> is investigated as an alternative to NiO<sub>*x*</sub> where the work function of MoS<sub>2</sub> is tuned through oxygen plasma treatment to increase its work function. The experimental examination of defect tolerance of BiOI is conducted in chapter three. BiOI films are vacuum-annealed to induce surface composition changes. Large changes in surface atomic fractions (reduction in iodine and bismuth by 40% and 5% respectively, and increase in oxygen by >45%) are observed. These significant changes do not affect the electronic and optoelectronic properties, in contrast to traditional covalent semiconductors. The applicability of low-temperature (≤ 200 °C) atmospheric pressure spatial atomic layer deposited (AP-SALD) Cu<sub>2</sub>O for use in *p*-type TFTs is explored in chapter four. The performance of AP-SALD Cu<sub>2</sub>O is comparable to atomic layer deposition (ALD) grown Cu<sub>2</sub>O with an I<sub>*ON*</sub>/I<sub>*OFF*</sub> ratio of 10<sup>3</sup>, and field-effect mobility between 10<sup>-4</sup> - 10<sup>-3</sup> cm<sup>2</sup>·V<sup>-1</sup>·s<sup>-1</sup>, illustrating the potential of AP-SALD grown films for integration with flexible substrates.","abstract_html":"The focus of this thesis is on developing two next-generation inorganic materials for thin-film device applications, namely photovoltaics and thin-film transistors. Both of these device applications are crucial in today’s technology-based society with photovoltaics enabling sustainable generation of electricity whilst advancements in thin-film transistors allow for development of low-power, efficient electronic devices. BiOI, a non-toxic, perovskite-inspired material is investigated for photovoltaics (PVs) whilst Cu&lt;sub&gt;2&lt;/sub&gt;O, with a reasonably high predicted hole mobility is developed for *p*-type thin-film transistors (TFTs). These novel materials are fabricated with scalable processing techniques which enable lower manufacturing costs and improve energy efficiency. In the first results chapter, the suitability of non-toxic BiOI as a photovoltaic material is investigated. Dense BiOI films grown by thermal chemical vapour deposition (CVD) incorporated into an all-inorganic ITO/NiO&lt;sub&gt;*x*&lt;/sub&gt;/BiOI/ZnO/Al stack demonstrate high external quantum efficiencies (80% at 450 nm wavelength). However, the 1.9 eV band gap of BiOI is not matched to terrestrial solar spectra; the PVs achieve 1.8% power conversion efficiency. Owing to improved spectral matching with indoor light spectra, BiOI devices improve in efficiency to 4.37% under 1000 lux white light emitting diode indoor illumination, and millimetre-area BiOI devices are sufficient to power novel carbon nanotube inverters. The factor limiting further efficiency gains is downwards band-bending at the BiOI/NiO&lt;sub&gt;*x*&lt;/sub&gt; interface owing to NiO&lt;sub&gt;*x*&lt;/sub&gt; having a lower work function. In the second chapter, MoS&lt;sub&gt;2&lt;/sub&gt; is investigated as an alternative to NiO&lt;sub&gt;*x*&lt;/sub&gt; where the work function of MoS&lt;sub&gt;2&lt;/sub&gt; is tuned through oxygen plasma treatment to increase its work function. The experimental examination of defect tolerance of BiOI is conducted in chapter three. BiOI films are vacuum-annealed to induce surface composition changes. Large changes in surface atomic fractions (reduction in iodine and bismuth by 40% and 5% respectively, and increase in oxygen by &gt;45%) are observed. These significant changes do not affect the electronic and optoelectronic properties, in contrast to traditional covalent semiconductors. The applicability of low-temperature (≤ 200 °C) atmospheric pressure spatial atomic layer deposited (AP-SALD) Cu&lt;sub&gt;2&lt;/sub&gt;O for use in *p*-type TFTs is explored in chapter four. The performance of AP-SALD Cu&lt;sub&gt;2&lt;/sub&gt;O is comparable to atomic layer deposition (ALD) grown Cu&lt;sub&gt;2&lt;/sub&gt;O with an I&lt;sub&gt;*ON*&lt;/sub&gt;/I&lt;sub&gt;*OFF*&lt;/sub&gt; ratio of 10&lt;sup&gt;3&lt;/sup&gt;, and field-effect mobility between 10&lt;sup&gt;-4&lt;/sup&gt; - 10&lt;sup&gt;-3&lt;/sup&gt; cm&lt;sup&gt;2&lt;/sup&gt;·V&lt;sup&gt;-1&lt;/sup&gt;·s&lt;sup&gt;-1&lt;/sup&gt;, illustrating the potential of AP-SALD grown films for integration with flexible substrates.","abstract_has_math":false,"creators":["Huq, Tahmida"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Driscoll, Judith"],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-03-05","date_published":"2023-03-05","updated_at":"2026-07-22T22:24:30Z","subjects":["atmospheric pressure spatial atomic layer deposition","bismuth oxyiodide","copper oxide","indoor photovoltaics","nanotechnology","perovskite-inspired materials","photovoltaics","thin-film transistors"],"languages":["eng"],"rights":[],"rights_urls":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/775cc775-d4be-4642-aeaa-495ed37c0e86/download","http://purl.org/NET/rdflicense/allrightsreserved"],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.101974","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Driscoll, Judith"]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["PragmatIC Aziz Foundation"]},{"key":"dc:creator","label":"Author","values":["Huq, Tahmida"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2023-03-05"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/358203"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["atmospheric pressure spatial atomic layer deposition","bismuth oxyiodide","copper oxide","indoor photovoltaics","nanotechnology","perovskite-inspired materials","photovoltaics","thin-film transistors"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/775cc775-d4be-4642-aeaa-495ed37c0e86/download","http://purl.org/NET/rdflicense/allrightsreserved"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.17863/CAM.101974"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/045aaa8d-1fb4-4f56-a2ad-2d5dce763141/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The focus of this thesis is on developing two next-generation inorganic materials for thin-film device applications, namely photovoltaics and thin-film transistors. Both of these device applications are crucial in today’s technology-based society with photovoltaics enabling sustainable generation of electricity whilst advancements in thin-film transistors allow for development of low-power, efficient electronic devices. BiOI, a non-toxic, perovskite-inspired material is investigated for photovoltaics (PVs) whilst Cu<sub>2</sub>O, with a reasonably high predicted hole mobility is developed for *p*-type thin-film transistors (TFTs). These novel materials are fabricated with scalable processing techniques which enable lower manufacturing costs and improve energy efficiency. In the first results chapter, the suitability of non-toxic BiOI as a photovoltaic material is investigated. Dense BiOI films grown by thermal chemical vapour deposition (CVD) incorporated into an all-inorganic ITO/NiO<sub>*x*</sub>/BiOI/ZnO/Al stack demonstrate high external quantum efficiencies (80% at 450 nm wavelength). However, the 1.9 eV band gap of BiOI is not matched to terrestrial solar spectra; the PVs achieve 1.8% power conversion efficiency. Owing to improved spectral matching with indoor light spectra, BiOI devices improve in efficiency to 4.37% under 1000 lux white light emitting diode indoor illumination, and millimetre-area BiOI devices are sufficient to power novel carbon nanotube inverters. The factor limiting further efficiency gains is downwards band-bending at the BiOI/NiO<sub>*x*</sub> interface owing to NiO<sub>*x*</sub> having a lower work function. In the second chapter, MoS<sub>2</sub> is investigated as an alternative to NiO<sub>*x*</sub> where the work function of MoS<sub>2</sub> is tuned through oxygen plasma treatment to increase its work function. The experimental examination of defect tolerance of BiOI is conducted in chapter three. BiOI films are vacuum-annealed to induce surface composition changes. Large changes in surface atomic fractions (reduction in iodine and bismuth by 40% and 5% respectively, and increase in oxygen by >45%) are observed. These significant changes do not affect the electronic and optoelectronic properties, in contrast to traditional covalent semiconductors. The applicability of low-temperature (≤ 200 °C) atmospheric pressure spatial atomic layer deposited (AP-SALD) Cu<sub>2</sub>O for use in *p*-type TFTs is explored in chapter four. The performance of AP-SALD Cu<sub>2</sub>O is comparable to atomic layer deposition (ALD) grown Cu<sub>2</sub>O with an I<sub>*ON*</sub>/I<sub>*OFF*</sub> ratio of 10<sup>3</sup>, and field-effect mobility between 10<sup>-4</sup> - 10<sup>-3</sup> cm<sup>2</sup>·V<sup>-1</sup>·s<sup>-1</sup>, illustrating the potential of AP-SALD grown films for integration with flexible substrates."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["c3db284408ce62b62b48c91b7e89c2cc","87eda9de84448d1f82354d60eee3eb5f"]},{"key":"dc:title","label":"Title","values":["Developing next generation, non-toxic, inorganic materials for photovoltaics and thin-film transistors"]}]}],"canonical_facts":{"dc:contributor.advisor":["Driscoll, Judith"],"dc:contributor.sponsor":["PragmatIC Aziz Foundation"],"dc:creator":["Huq, Tahmida"],"dc:date.issued":["2023-03-05"],"dc:description.abstract":["The focus of this thesis is on developing two next-generation inorganic materials for thin-film device applications, namely photovoltaics and thin-film transistors. Both of these device applications are crucial in today’s technology-based society with photovoltaics enabling sustainable generation of electricity whilst advancements in thin-film transistors allow for development of low-power, efficient electronic devices. BiOI, a non-toxic, perovskite-inspired material is investigated for photovoltaics (PVs) whilst Cu<sub>2</sub>O, with a reasonably high predicted hole mobility is developed for *p*-type thin-film transistors (TFTs). These novel materials are fabricated with scalable processing techniques which enable lower manufacturing costs and improve energy efficiency. In the first results chapter, the suitability of non-toxic BiOI as a photovoltaic material is investigated. Dense BiOI films grown by thermal chemical vapour deposition (CVD) incorporated into an all-inorganic ITO/NiO<sub>*x*</sub>/BiOI/ZnO/Al stack demonstrate high external quantum efficiencies (80% at 450 nm wavelength). However, the 1.9 eV band gap of BiOI is not matched to terrestrial solar spectra; the PVs achieve 1.8% power conversion efficiency. Owing to improved spectral matching with indoor light spectra, BiOI devices improve in efficiency to 4.37% under 1000 lux white light emitting diode indoor illumination, and millimetre-area BiOI devices are sufficient to power novel carbon nanotube inverters. The factor limiting further efficiency gains is downwards band-bending at the BiOI/NiO<sub>*x*</sub> interface owing to NiO<sub>*x*</sub> having a lower work function. In the second chapter, MoS<sub>2</sub> is investigated as an alternative to NiO<sub>*x*</sub> where the work function of MoS<sub>2</sub> is tuned through oxygen plasma treatment to increase its work function. The experimental examination of defect tolerance of BiOI is conducted in chapter three. BiOI films are vacuum-annealed to induce surface composition changes. Large changes in surface atomic fractions (reduction in iodine and bismuth by 40% and 5% respectively, and increase in oxygen by >45%) are observed. These significant changes do not affect the electronic and optoelectronic properties, in contrast to traditional covalent semiconductors. The applicability of low-temperature (≤ 200 °C) atmospheric pressure spatial atomic layer deposited (AP-SALD) Cu<sub>2</sub>O for use in *p*-type TFTs is explored in chapter four. The performance of AP-SALD Cu<sub>2</sub>O is comparable to atomic layer deposition (ALD) grown Cu<sub>2</sub>O with an I<sub>*ON*</sub>/I<sub>*OFF*</sub> ratio of 10<sup>3</sup>, and field-effect mobility between 10<sup>-4</sup> - 10<sup>-3</sup> cm<sup>2</sup>·V<sup>-1</sup>·s<sup>-1</sup>, illustrating the potential of AP-SALD grown films for integration with flexible substrates."],"dc:format.checksum.md5":["c3db284408ce62b62b48c91b7e89c2cc","87eda9de84448d1f82354d60eee3eb5f"],"dc:identifier.doi":["https://doi.org/10.17863/CAM.101974"],"dc:identifier.uri":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/045aaa8d-1fb4-4f56-a2ad-2d5dce763141/download"],"dc:language":["eng"],"dc:publisher.institution":["University of Cambridge"],"dc:relation.isreferencedby.uri":["https://www.repository.cam.ac.uk/handle/1810/358203"],"dc:rights":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/775cc775-d4be-4642-aeaa-495ed37c0e86/download","http://purl.org/NET/rdflicense/allrightsreserved"],"dc:subject":["atmospheric pressure spatial atomic layer deposition","bismuth oxyiodide","copper oxide","indoor photovoltaics","nanotechnology","perovskite-inspired materials","photovoltaics","thin-film transistors"],"dc:title":["Developing next generation, non-toxic, inorganic materials for photovoltaics and thin-film transistors"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-22T22:24:30Z"}