Solution-Processed Inorganic Thin-Film Photovoltaic Devices (SolPV)

Lead Research Organisation: University of Bristol
Department Name: Chemistry

Abstract

The Clean Growth Strategy, a core element of the UK Industrial Strategy, aims at delivering a high-tech vibrant low-carbon economy. The UK has two legally binding targets in the medium term which requires urgent drastic action,: (i) clean, smart and flexible power to deliver 80% of electricity generation by 2032 and (ii) 'net-zero' carbon emission by 2050 in every aspect of the economy. The effective integration of renewable energy sources in every sector is crucial, with solar energy playing a central role in this transformation.

A key area of expansion in the field of solar conversion to electrical energy, known as photovoltaic (PV), is the integration in building and infrastructure in highly urbanised environments. For instance, the size of the building-integrated PV industry is reaching over $2Bn in the US alone. While mature Si technologies will continue to dominate utility-scale electricity generation, system-integrated PV requires technologies based on thin-film semiconductor materials which can be deposited onto a variety of substrates. SolPV will investigate the science of manufacturing PV devices based on the two leading inorganic thin-film technologies, Cu(In,Ga)(S,Se)2 (CIGS) and Cu2ZnSn(S,Se)4 (CZTS), based on scalable solution processes.

SolPV aims at taking the performance of solution-processed CIGS and CZTS devices to power conversion efficiencies above 15% using scalable manufacturing routes and Cd-free architectures. Conventional CIGS and CZTS device architecture (commonly referred to as 'substrate') consists of soda-lime glass/Mo/absorber/CdS/i-ZnO/Al:ZnO. The SolPV strategy involves:
1- optimisation of the absorber precursor formulation to implement scalable manufacturing methods such as slot-dye and bar-coating,
2- design thermal processing strategies to achieve control crystallisation and composition of the absorber
3- interfacial engineering of the junction between the absorber layer and buffer layer, including replacement of Cd-based compounds.

The work programme is divided into two phases: Phase I - targeting high-efficiency standard substrate architectures, and Phase II - focused on Interface engineering for high-efficiency Cd-free architectures. We will combine solution-processing approaches with cutting-edge manufacturing tools such as atomic layer deposition to achieve accurate control of the semiconductor junction composition. Furthermore, we will assess the capacity of transferring these advanced manufacturing approaches to other supports such as composite materials.

To achieve the ambitious SolPV targets, three leading centres in CIGS and CZTS research are partnering with the Centre for Process Innovation Catapult to ensure that innovation is not only driven by device but also by scalable manufacturing. The consortium also includes industrial partners supporting critical areas of the work programme.
 
Description The SolPV network aims at developing scalable-solution based methods for inorganic thin-film solar cells, while replacing toxic and critical elements. The strategy involves preparing stable solutions containing the elements of the inorganic absorber, depositing the solution via spin-coating and heating step (dry precursor), reactive annealing in the presence of Se to generate Cu2ZnSn(S,Se)4 (solar absorber), deposition of the buffer layer, device completion and testing. In this reporting period, key findings during this reporting period include:
1- Rationalising the bonding and molecular configuration in the solution precursors used for solar absorbers
2- Determining how molecular structure in solution affects the structure and morphology of dry precursor films and grain growth of the solar absorber
3- Establishing a link between composition of the molecular precursor and device performance
4- Develop a range of Cd-free buffer layers by atomic layer deposition (ALD) of ZnSnOx layers
5- Explore crystallisation and device performance using transparent F:doped SnO2 films as substrates, towards developing bifacial PV devices

These studies have generated a wealth of information which is currently under review for publication. The impact of this research is relevant to creating new light-weight PV technologies that can be integrated into buildings.
Exploitation Route The outcomes of this research can have an impact in manufacturing new green technologies, in particular decentralised power generating from solar energy. We aim at creating a new approach for building integrated PV systems based on stable, non-toxic, non-critical and scalable materials.
Sectors Chemicals

Construction

Energy

Manufacturing

including Industrial Biotechology

 
Title Correlating Orbital Composition and Activity of LaMnxNi1-xO3 Nanostructures Towards Oxygen Electrocatalysis 
Description Detailed correlation between electronic structure of transition metal oxides and their oxygen electrocatalytic activity 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://data.bris.ac.uk/data/dataset/3544nql45ox1o2ptxhejnmmzjk/
 
Title Data from photoluminescence spectroscopy, admittance spectroscopy, photoelectron emission microscopy, current-voltage characteristics, and spectral response of quantum efficiency measurements on Cu2ZnZnSnS4 (CZTS) films and solar cells as a function of... 
Description This is the dataset used in the journal article to be published in American Chemical Society's Applied Energy Materials. Article Title: Mapping the Energetics of Defect States in Cu2ZnSnS4 films and the Impact of Sb DopingAuthors: Devendra Tiwari, Michael V. Yakushev, Tristan Koehler, Mattia Cattelan, Neil Fox, Robert W. Martin, Reiner Klenk and David J FerminDOI: https://10.1021/acsaem.1c03729 The dataset was produced in collaboration with colleagues from University of Bristol, Strathclyde University and Helmholtz Zentrum Berlin. The dataset contains .csv files and can be accessed can be using any text editor or any spreadsheet software. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://figshare.northumbria.ac.uk/articles/dataset/Data_from_photoluminescence_spectroscopy_admitta...
 
Title Decoupling the impact of bulk and surface point defects on the photoelectrochemical properties of LaFeO3 thin films 
Description Data associated with the article published in Chemical Science 2022 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://data.bris.ac.uk/data/dataset/1608ds02po8it2jufacsom4nm8/
 
Description Development of Interlayers for Highly Stable Perovskite Solar Cells 
Organisation Korea Research Institute of Chemical Technology
Country Korea, Republic of 
Sector Public 
PI Contribution We have been working with the team led by Dr. Helen Hejin Park on the characterisation of ultrathin metal oxide layers grown by atomic layer depsoition (ALD) tools. We have been using techniques such as photoemission of emission of electron microscopy and electrochemical methos to characterise the workfunction of the materials and the dopant level.
Collaborator Contribution ALD is a key tool in our SolPV programme, and this collaboration have been very fruitfull in accessing novel precursors as well as sharing best practices in film deposition. We have also been able to access some of the facilities for solar cell fabrication and characterisation
Impact 1- One joint paper published, while two other papers are currently in preparation. 2- Two research visits by the Korean team to University Bristol in 2022 and 2023 3- One research visit to KRICT by the the Bristol team in 2023
Start Year 2022
 
Description Electrochem2023 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact National Electrochemistry conference sponsored by the Royal Society of Chemistry, the Society of Chemical Industries and the Institute of Corrosion. The event took place at the University of Bristol between 10 to 12th September 2023. It was attended by more 240 delegates from all over the world, covering areas associated with electrochemical energy conversion and storage, electrochemical sensing, electrosynthesis and corrosion science.
Year(s) Of Engagement Activity 2023
URL https://www.rsc.org/events/detail/76467/electrochem-2023
 
Description Faraday Discussion on Emerging Inorganic Materials in Thin Film Photovoltaic 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was the first Royal Society of Chemistry Faraday Discussions entirely devoted to photovoltaic technologies involving leading international porfessionals and academics.
Year(s) Of Engagement Activity 2022
URL https://pubs.rsc.org/en/journals/articlecollectionlanding?sercode=fd&themeid=05630b5f-249a-47d0-b69d...
 
Description GW4 Net Zero Ambassador 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact GW4 Net Zero Alliance involves the Universities of Bristol, Bath, Cardiff and Exeter, working together to accelerating the transition to Net Zero. We engage with industries, professionals and local governements to develop solutions in challenges such as decarbonisation of transport and deployment of the hydrogen economy.
Year(s) Of Engagement Activity 2020,2021,2022,2023
URL https://gw4.ac.uk/net-zero/