High resolution mapping of performance and degradation mechanisms in printable photovoltaic devices
Lead Research Organisation:
Imperial College London
Department Name: Physics
Abstract
PV materials that can be processed from solution at low temperature offer a route to low cost and low emebedded energy PV modules with potential for integration into buildings and other infrastructure to generate clean electricity on a large scale. Organic PV (OPV) has attracted intense research interest; impressive improvements in efficiency and in fabrication knowhow have been demonstrated. Lead halide perovskites solar cells (PSC) are based on a newly rediscovered active layer material and have shown radical improvements in start-of-life efficiency with recent optimisation of device structure and processing.
However both technology types are challenged by losses in power conversion efficiency under operation, even though they are believed capable of stabilised efficiency of 15-20%. The limited operational stability of such devices inhibits their widespread commercial application. To overcome this there is a need to understand the sources of efficiency loss, both at start-of-life and during ageing in typical operating environments.
Until now, most studies of novel PV device stability have amounted to empirical studies of the evolution of performance parameters for different materials or device structures in different environments, and scientific attention has focussed largely on the oxidative stability of the photoactive layer. Relatively little attention has been paid to the electrodes and interlayers, even though these layers are often the first to fail and additionally they are partly responsible for protecting the active layers. In addition, most performance metrics probe the macroscopic device performance and although imaging methods have been used to observe heterogeneous material properties during ageing mapping techniques have not yet been used to provide detailed insight into the chemical, electrochemical and physical mechanism of current and voltage loss.
This proposal seeks to develop a set of interlinked experimental techniques to probe the basic mechanisms underpinning device degradation and failure in two leading classes of printable photovoltaic (PV) materials, organic photovoltaics (OPV) and organohalide perovskite solar cells (PSCs). Our approach is to develop and adapt two-dimensional mapping techniques that probe the local chemical and electronic state of the materials and combine them with device-scale electrical measurement, structural characterisation and modelling in order to analyse the degradation mechanisms, to identify the local conditions that lead to degradation and to design strategies to inhibit the progression of failure mechanisms. The mapping tools will be developed with the potential to be applied during module manufacture and quality control.
However both technology types are challenged by losses in power conversion efficiency under operation, even though they are believed capable of stabilised efficiency of 15-20%. The limited operational stability of such devices inhibits their widespread commercial application. To overcome this there is a need to understand the sources of efficiency loss, both at start-of-life and during ageing in typical operating environments.
Until now, most studies of novel PV device stability have amounted to empirical studies of the evolution of performance parameters for different materials or device structures in different environments, and scientific attention has focussed largely on the oxidative stability of the photoactive layer. Relatively little attention has been paid to the electrodes and interlayers, even though these layers are often the first to fail and additionally they are partly responsible for protecting the active layers. In addition, most performance metrics probe the macroscopic device performance and although imaging methods have been used to observe heterogeneous material properties during ageing mapping techniques have not yet been used to provide detailed insight into the chemical, electrochemical and physical mechanism of current and voltage loss.
This proposal seeks to develop a set of interlinked experimental techniques to probe the basic mechanisms underpinning device degradation and failure in two leading classes of printable photovoltaic (PV) materials, organic photovoltaics (OPV) and organohalide perovskite solar cells (PSCs). Our approach is to develop and adapt two-dimensional mapping techniques that probe the local chemical and electronic state of the materials and combine them with device-scale electrical measurement, structural characterisation and modelling in order to analyse the degradation mechanisms, to identify the local conditions that lead to degradation and to design strategies to inhibit the progression of failure mechanisms. The mapping tools will be developed with the potential to be applied during module manufacture and quality control.
Planned Impact
As well as communicating the scientific progress of the research through publication of results in leading journals in material science, chemistry and physics, the team will communicate with a wider audience through public engagement activities and the media.
To access the general public we will use our experience in communicating science. Prof Nelson has ample recent experience in communicating research results through broadcast (for example interviews on Radio 4 'In Our Time' and Australian Broadcast Corporation's 'The Science Show' during 2012) and print (articles in The Guardian and Sublime Magazine during 2012) media. We will use our contacts in the media and with lay organisations to communicate the results of our research.
Lower cost photovoltaic technologies have a high potential for contribution to future power supply, particularly in the developing world and to carbon emissions mitigation. Prof Nelson leads the Mitigation team at The Grantham Institute for Climate Change and the Environment at Imperial College, which runs an active programme of seminars, briefing papers, discussions with policy makers and other stakeholders. During the last year she has presented research results on emerging PV technologies to members of government departments (DECC, DFID), the International Energy Agency, funding bodies, energy economists and science media. In addition Prof Nelson has written a briefing papers for the Grantham Institute on the potential of solar power and on estimation of the mitigation potential of new renewable technologies and has liaised directly with DECC about the subject. This provides a direct route to communicate significant results from this research to a wider energy and policy making community.
The Centre for Plastic Electronics (CPE) at Imperial is one of the five UK centres of excellence in PE and as such has access to the network of affiliated companies (such as Merck, BASF, Bayer, Solvay, hp, Cambridge Display Technology, Plastic Logic, Plextronics, Solar Press), government departments and research institutions that are active in developing devices and materials for organic electronics. Advances will be communicated via this network and other partners in the CPE and we will proactively pursue these relationships to exploit potential new developments and contribute to wealth generation.
Our research programme is directly relevant to companies seeking to develop new experimental capability and new organic photovoltaic devices. For this reason we have engaged Renishaw, Perkin Elmer and Ossila as project partners, with the aim of evaluating the industrial use of our spatially resolved characterization techniques in collaboration with them. Ossila stand to benefit through early access to knowhow that can improve quality control and diagnostic testing of organic photovoltaics during production. In addition, through existing research collaborations at the SPECIFIC IKC where Tsoi and Charbonnean are based we have direct contact with other companies working on commercializing novel photovoltaic technologies (Solar Press, Oxford Photovoltaics, Molecular Photovoltaics,Tata Steel, G24i) and we will exploit these contacts to publicise the potential of the methods being developedin this programme. Finally, Prof Lidzey and Prof Nelson are members of the new EPSRC SuperSolar Hub and as such have access to the UK academic and industrial community involved in solar energy technology.
To access the general public we will use our experience in communicating science. Prof Nelson has ample recent experience in communicating research results through broadcast (for example interviews on Radio 4 'In Our Time' and Australian Broadcast Corporation's 'The Science Show' during 2012) and print (articles in The Guardian and Sublime Magazine during 2012) media. We will use our contacts in the media and with lay organisations to communicate the results of our research.
Lower cost photovoltaic technologies have a high potential for contribution to future power supply, particularly in the developing world and to carbon emissions mitigation. Prof Nelson leads the Mitigation team at The Grantham Institute for Climate Change and the Environment at Imperial College, which runs an active programme of seminars, briefing papers, discussions with policy makers and other stakeholders. During the last year she has presented research results on emerging PV technologies to members of government departments (DECC, DFID), the International Energy Agency, funding bodies, energy economists and science media. In addition Prof Nelson has written a briefing papers for the Grantham Institute on the potential of solar power and on estimation of the mitigation potential of new renewable technologies and has liaised directly with DECC about the subject. This provides a direct route to communicate significant results from this research to a wider energy and policy making community.
The Centre for Plastic Electronics (CPE) at Imperial is one of the five UK centres of excellence in PE and as such has access to the network of affiliated companies (such as Merck, BASF, Bayer, Solvay, hp, Cambridge Display Technology, Plastic Logic, Plextronics, Solar Press), government departments and research institutions that are active in developing devices and materials for organic electronics. Advances will be communicated via this network and other partners in the CPE and we will proactively pursue these relationships to exploit potential new developments and contribute to wealth generation.
Our research programme is directly relevant to companies seeking to develop new experimental capability and new organic photovoltaic devices. For this reason we have engaged Renishaw, Perkin Elmer and Ossila as project partners, with the aim of evaluating the industrial use of our spatially resolved characterization techniques in collaboration with them. Ossila stand to benefit through early access to knowhow that can improve quality control and diagnostic testing of organic photovoltaics during production. In addition, through existing research collaborations at the SPECIFIC IKC where Tsoi and Charbonnean are based we have direct contact with other companies working on commercializing novel photovoltaic technologies (Solar Press, Oxford Photovoltaics, Molecular Photovoltaics,Tata Steel, G24i) and we will exploit these contacts to publicise the potential of the methods being developedin this programme. Finally, Prof Lidzey and Prof Nelson are members of the new EPSRC SuperSolar Hub and as such have access to the UK academic and industrial community involved in solar energy technology.
Publications
Yan Y
(2018)
Correlating Nanoscale Morphology with Device Performance in Conventional and Inverted PffBT4T-2OD:PC 71 BM Polymer Solar Cells
in ACS Applied Energy Materials
Alhazmi N
(2020)
Perovskite Crystallization Dynamics during Spin-Casting: An In Situ Wide-Angle X-ray Scattering Study.
in ACS applied energy materials
Pineda De La O E
(2021)
Influence of Additives on the In Situ Crystallization Dynamics of Methyl Ammonium Lead Halide Perovskites.
in ACS applied energy materials
Smith JA
(2020)
Rapid Scalable Processing of Tin Oxide Transport Layers for Perovskite Solar Cells.
in ACS applied energy materials
Speller EM
(2017)
Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics.
in ACS applied materials & interfaces
Pérez GE
(2019)
Determination of the Thin-Film Structure of Zwitterion-Doped Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate): A Neutron Reflectivity Study.
in ACS applied materials & interfaces
Bishop JE
(2018)
High-Efficiency Spray-Coated Perovskite Solar Cells Utilizing Vacuum-Assisted Solution Processing.
in ACS applied materials & interfaces
Tuladhar S
(2016)
Low Open-Circuit Voltage Loss in Solution-Processed Small-Molecule Organic Solar Cells
in ACS Energy Letters
Vezie M
(2019)
Impact of Marginal Exciton-Charge-Transfer State Offset on Charge Generation and Recombination in Polymer:Fullerene Solar Cells
in ACS Energy Letters
Abdi-Jalebi M
(2018)
Dedoping of Lead Halide Perovskites Incorporating Monovalent Cations.
in ACS nano
Yang Y
(2017)
Emergent Properties of an Organic Semiconductor Driven by its Molecular Chirality.
in ACS nano
Pham H
(2020)
All-Rounder Low-Cost Dopant-Free D-A-D Hole-Transporting Materials for Efficient Indoor and Outdoor Performance of Perovskite Solar Cells
in Advanced Electronic Materials
Wong-Stringer M
(2018)
High-Performance Multilayer Encapsulation for Perovskite Photovoltaics
in Advanced Energy Materials
Mohamad D
(2016)
Spray-Cast Multilayer Organometal Perovskite Solar Cells Fabricated in Air
in Advanced Energy Materials
Pham H
(2018)
Molecular Engineering Using an Anthanthrone Dye for Low-Cost Hole Transport Materials: A Strategy for Dopant-Free, High-Efficiency, and Stable Perovskite Solar Cells
in Advanced Energy Materials
Luke J
(2019)
Twist and Degrade-Impact of Molecular Structure on the Photostability of Nonfullerene Acceptors and Their Photovoltaic Blends
in Advanced Energy Materials
Du T
(2018)
Elucidating the Origins of Subgap Tail States and Open-Circuit Voltage in Methylammonium Lead Triiodide Perovskite Solar Cells
in Advanced Functional Materials
Li W
(2017)
Contrasting Effects of Energy Transfer in Determining Efficiency Improvements in Ternary Polymer Solar Cells
in Advanced Functional Materials
Barrows A
(2016)
Monitoring the Formation of a CH 3 NH 3 PbI 3- x Cl x Perovskite during Thermal Annealing Using X-Ray Scattering
in Advanced Functional Materials
Lilliu S
(2016)
Mapping Morphological and Structural Properties of Lead Halide Perovskites by Scanning Nanofocus XRD
in Advanced Functional Materials
Eisner F
(2021)
Emissive Charge-Transfer States at Hybrid Inorganic/Organic Heterojunctions Enable Low Non-Radiative Recombination and High-Performance Photodetectors
in Advanced Materials
Fei Z
(2018)
An Alkylated Indacenodithieno[3,2-b]thiophene-Based Nonfullerene Acceptor with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies Greater than 13% with Low Voltage Losses.
in Advanced materials (Deerfield Beach, Fla.)
Pérez G
(2020)
Improved Performance and Stability of Organic Solar Cells by the Incorporation of a Block Copolymer Interfacial Layer
in Advanced Materials Interfaces
Zhang Y
(2018)
Current Status of Outdoor Lifetime Testing of Organic Photovoltaics.
in Advanced science (Weinheim, Baden-Wurttemberg, Germany)
Masters RC
(2019)
Mapping Polymer Molecular Order in the SEM with Secondary Electron Hyperspectral Imaging.
in Advanced science (Weinheim, Baden-Wurttemberg, Germany)
Barbé J
(2018)
Characterization of stability of benchmark organic photovoltaic films after proton and electron bombardments
in Applied Physics Letters
Eisner F
(2021)
Color-tunable hybrid heterojunctions as semi-transparent photovoltaic windows for photoelectrochemical water splitting
in Cell Reports Physical Science
Tsevas K
(2021)
Controlling PbI 2 Stoichiometry during Synthesis to Improve the Performance of Perovskite Photovoltaics
in Chemistry of Materials
Leguy A
(2015)
Reversible Hydration of CH 3 NH 3 PbI 3 in Films, Single Crystals, and Solar Cells
in Chemistry of Materials
Jain S
(2019)
Green fabrication of stable lead-free bismuth based perovskite solar cells using a non-toxic solvent
in Communications Chemistry
Hynes E
(2019)
Interfacial width and phase equilibrium in polymer-fullerene thin-films
in Communications Physics
Lilliu S
(2016)
Grain rotation and lattice deformation during perovskite spray coating and annealing probed in situ by GI-WAXS
in CrystEngComm
Moia D
(2019)
Ionic-to-electronic current amplification in hybrid perovskite solar cells: ionically gated transistor-interface circuit model explains hysteresis and impedance of mixed conducting devices
in Energy & Environmental Science
Wong-Stringer M
(2019)
A flexible back-contact perovskite solar micro-module
in Energy & Environmental Science
Azzouzi M
(2022)
Reconciling models of interfacial state kinetics and device performance in organic solar cells: impact of the energy offsets on the power conversion efficiency.
in Energy & environmental science
Belisle R
(2017)
Interpretation of inverted photocurrent transients in organic lead halide perovskite solar cells: proof of the field screening by mobile ions and determination of the space charge layer widths
in Energy & Environmental Science
Lee H
(2018)
The role of fullerenes in the environmental stability of polymer:fullerene solar cells
in Energy & Environmental Science
Bracher C
(2017)
Degradation of inverted architecture CH 3 NH 3 PbI 3- x C l x perovskite solar cells due to trapped moisture
in Energy Science & Engineering
De Rossi F
(2020)
An Interlaboratory Study on the Stability of All-Printable Hole Transport Material-Free Perovskite Solar Cells
in Energy Technology
S Al-Azzawi A
(2021)
Synthesis, Optical and Electrochemical Properties of Naphthothiadiazole-Based Donor-Acceptor Polymers and Their Photovoltaic Applications
in International Journal of Electrochemical Science
Calado P
(2022)
Driftfusion: an open source code for simulating ordered semiconductor devices with mixed ionic-electronic conducting materials in one dimension
in Journal of Computational Electronics
Speller E
(2019)
From fullerene acceptors to non-fullerene acceptors: prospects and challenges in the stability of organic solar cells
in Journal of Materials Chemistry A
Sasitharan K
(2020)
Metal-organic framework nanosheets for enhanced performance of organic photovoltaic cells
in Journal of Materials Chemistry A
Hu Y
(2018)
Identifying and controlling phase purity in 2D hybrid perovskite thin films
in Journal of Materials Chemistry A
Wong-Stringer M
(2017)
Efficient perovskite photovoltaic devices using chemically doped PCDTBT as a hole-transport material
in Journal of Materials Chemistry A
Description | We have discovered that the relationship between ion migration and surface recombination is largely responsible for hysteresis in perovskite solar cells. |
Exploitation Route | more efficient solar cells |
Sectors | Electronics,Energy |
URL | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192183/ |
Description | Modelling work done as part of this award by Dr Piers Barnes has resulted in an open source modelling software for systems with coupled electronic and ionic current called DriftFusion which is available on GitHub. (https://github.com/barnesgroupICL/Driftfusion) The software has been written up in an article "Driftfusion: An open source code for simulating ordered semiconductor devices with mixed ionic-electronic conducting materials in one-dimension" by P. Calado et al, hich is now published. The software has been developed and is available on teh open source l=platform for use by otehr groups |
Sector | Electronics,Energy,Environment |
Impact Types | Societal,Economic |
Description | Application Targeted and Integrated Photovoltaics - Enhancing UK Capability in Solar |
Amount | £5,991,738 (GBP) |
Funding ID | EP/T028513/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 07/2020 |
End | 06/2025 |
Title | Driftfusion |
Description | First official release of Driftfusion. The recent application of lead-halide perovskites as an active layer material in thin film semiconductor devices including solar cells, light emitting diodes (LEDs), and memristors has motivated the development of several new drift-diffusion models that can include the effects of both mobile electronic and ionic charge carriers. Here, we present Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to simulate devices with virtually any number of layers and with up to four charge carrier species (electrons and holes by default plus up to two ionic species). The time-dependent carrier continuity equations are fully-coupled to Poisson's equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to the material parameters, users have direct access to adapt carrier transport, recombination and generation models as well as the system boundary conditions. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced. |
Type Of Technology | Software |
Year Produced | 2020 |
Open Source License? | Yes |
URL | https://zenodo.org/record/3670154 |
Title | Driftfusion |
Description | First official release of Driftfusion. The recent application of lead-halide perovskites as an active layer material in thin film semiconductor devices including solar cells, light emitting diodes (LEDs), and memristors has motivated the development of several new drift-diffusion models that can include the effects of both mobile electronic and ionic charge carriers. Here, we present Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to simulate devices with virtually any number of layers and with up to four charge carrier species (electrons and holes by default plus up to two ionic species). The time-dependent carrier continuity equations are fully-coupled to Poisson's equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to the material parameters, users have direct access to adapt carrier transport, recombination and generation models as well as the system boundary conditions. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced. |
Type Of Technology | Software |
Year Produced | 2020 |
Open Source License? | Yes |
URL | https://zenodo.org/record/3670155 |