Control of spin and coherence in electronic excitations in organic and hybrid organic/inorganic semiconductor structures

Lead Research Organisation: University of Cambridge
Department Name: Physics

Abstract

The field of organic electronics has continued to make great technological and scientific progress over the last 5 years and has given rise to a significant industry. The worldwide market for organic/printable electronics reached $12 billion in 2012, about half of which were organic light-emitting diode (OLED) displays. The efficiency of phosphorescent red and green as well as fluorescent blue OLEDs is already close to their theoretical maximum; to achieve this requires complex multilayer architectures. For future OLED applications, such as lighting, there is an important need for simpler device architectures and cheaper materials to meet demanding cost targets. Also organic field-effect transistors (OFETs) are now being used in commercial applications, including flexible active-matrix electronic paper displays. There continues to be an important need for organic semiconductors with higher carrier mobilities (>10-50 cm2/Vs) and electrical stability to enable a wider range of applications. Also organic solar cells based on distributed donor-acceptor heterojunctions have achieved steady improvements in performance with power conversion efficiencies of 10-11% now being reported for the best single-junction cells. However, in spite of intense research efforts the performance/efficiency and resulting cost of electricity of organic photovoltaics (OPV) is still not competitive with crystalline silicon solar cells. Two very significant breakthroughs made in the last two years have the potential to change this: (i) Our group in Cambridge has demonstrated 200% quantum efficiency in solar cells through the use of singlet fission, which opens up completely new architectures for solar energy harvesting. (ii) Hybrid organic-inorganic heterojunctions solar cells based on mixed halide perovskites have shown unexpected performance with efficiencies up to 16-17%, achieved in part through long exciton/charge diffusion lengths and low energetic disorder in the perovskite materials. This discovery may provide a solar cell technology that could realistically be competitive with silicon in a few years time.
Within this steadily advancing field of science and technology we identify three spectacular and unanticipated discoveries that create the opportunity for discontinuous advances. These are the focus of our programme: (i) Wavefunction delocalisation / coherence - We have been surprised that the degree of energetic disorder in conjugated polymers can now be reduced to levels at which it is no longer dominating the transport physics. It is very unexpected that this can be found in low-temperature processed non-crystalline materials. The associated coherence and delocalisation of excited state wavefunctions enables long-range electron transfer in non-covalent materials and heterojunctions; (ii) Organic-inorganic heterojunctions - The Oxford work on lead halide perovskites reveal low-temperature processed inorganic semiconductors with unexpectedly clean properties both in the bulk properties and also at interfaces with organic semiconductors. Understanding why it is possible to avoid electronic defect/trap states at these interfaces will form a major part of the programme. (iii) Spin - The unique spin physics of organic materials offers novel routes for controlling electronic processes that are not available in conventional, inorganic semiconductors. In particular, the process of singlet exciton fission to a pair of triplet excitons offers the potential of overcoming the Shockley-Queisser (SQ) efficiency limit in solar cells. The exploitation of these phenomena requires hybrid systems comprising both organic and inorganic semiconductors. Our programme grant builds on recent breakthroughs and is centered around the engineering of wavefunction delocalisation in organic and perovskite semiconductors. It will bring about a paradigm shift in the field of organic and inorganic large-area electronics and achieve step-changes in device performance.

Planned Impact

The programme is focussed on upstream, fundamental research that has the potential to form the scientific basis for the device performance of organic and hybrid inorganic-organic structures to rival and exceed that of conventional inorganic semiconductors. On a 5-20 year time scale organic and hybrid solar cells with current maximum power conversion efficiencies of 11% and 16%, respectively, have the potential to lower the cost of photovoltaic electricity to what is achievable by burning natural gas and to bring significant societal benefits. The level of control of the electronic processes at the critical heterojunction that we are aiming for in this programme could make efficiencies match or exceed those of silicon-based solar cells. Exploitation of the process of singlet fission in solar cells could break the fundamental Shockley-Queisser efficiency limit. A key feature of our proposal is that it also opens up new areas of application for solution-processed semiconductors, notably in quantum information. Applications in quantum information processing may appear ambitious at present, but we note that the solid-state quantum information community is engaging in a wider exploration of materials as limitations of widely investigated systems, such as nitrogen vacancy (NV) centres in diamond, are becoming apparent (see October 2013 focus issue of the MRS Bulletin on "Materials Issues in Quantum Computation").

All Investigators have extensive experience with the commercialisation of fundamental research, not only through founding successful start-up companies (Cambridge Display Technology (Friend), Plastic Logic (Sirringhaus, Friend), Eight19 (Friend, Greenham, Sirringhaus), Oxford Photovoltaics (Snaith), and Flexink (McCulloch)), but also through engaging with large, multinational technology and end user companies. The practical arrangements for protection and exploitation of project IP will follow the well-established technology transfer processes at the three Universities involved, using the services provided by their respective technology transfer offices (TTOs) Cambridge Enterprise, Isis Innovation, and Imperial Innovations. When, as expected, joint inventions arise, our collaboration agreement will encourage assignment to the TTO best placed to ensure successful exploitation, with appropriate sharing of future revenues.

Our impact strategy recognises that some of our results will not fit within this simple linear technology transfer model. Given the long-term nature of our research goals, we anticipate that some of our developments will be outside the immediate fields of interest of our industrial partners; they may be at low technology readiness level, require significant further research and development resources to establish commercial viability and/or their main application may be uncertain. In such situations we will explore alternative exploitation paths, including proof-of-concept studies supported by our TTOs, collaborations with the High Value Manufacturing Technology Innovation Centre and the EPSRC Centre for Innovative Manufacturing in Large-Area Electronics to establish feasibility or open-innovation collaborations with industrial partners (such as Hitachi) who have appropriately long-term vision.

The programme will provide an ideal interdisciplinary training environment for the researchers and associated PhD students, who will move on to become highly skilled researchers in academia and industry. Several of the senior post-doctoral researchers on our current programme grant have successfully attracted lectureships or personal EPSRC or Royal Society research fellowships. In their ability to bridge between fundamental science and industrial applications all five investigators have become role models to students and aspiring researchers and they will continue to be inspiring advocates for Science and Engineering in the UK.

Publications

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Stern HL (2015) Identification of a triplet pair intermediate in singlet exciton fission in solution. in Proceedings of the National Academy of Sciences of the United States of America

 
Description Research on the optoelectronic properties of lead halide perovskite semiconductors has revealed a very close connection between high solar cell efficiency and high luminescence efficiency. In particular, in efficient solar cells made with these materials, photo generated charges can recombine to regenerate a photon that is then re-absorbed and this re-generates electronic charges. This process of re-cycling of photons helps raise the open circuit voltage of the solar cell. Further advances have been made in the performance of lead halide perovskite LEDs. Perovskite LEDs with emission in the IR through to blue have been developed. New device architectures that allow close to 100% internal quantum efficiency for near IR and green have been demonstrated.

New transient optical spectroscopy techniques have been developed to probe early time electron-hole separation in organic solar cell devices. Measurements of the fission of singlet excitons to pairs of triplet excitons have been extended to a range of new molecular semiconductors.

With the organic semiconductors, new materials and LED architectures have been developed. A new class of organo-metallic complexes, carbene-metal-amides, was found to support very efficient LEDs, made possible because the metal (typically gold) allows rotational flexibility between electron donor and acceptor group and allows strong spin-orbit coupling that enables efficient use of both the spin singlet and spin triplet excitons produced by electron-hole capture during LED operation.

A big advance was made in using spin-radical organic semiconductors; contrary to expectations, it was possible to achieve electron injection into the half-filled spin-bearing SOMO level and also achieve hole injection into the lower-lying HOMO level, allowing efficient luminescence. Operation within the spin doublet manifold made it possible to achieve high efficiency (competing non-emissive excitations such as triplet excitons are avoided).
Exploitation Route optimisation of future solar cell design and performance
Sectors Electronics

Energy

 
Description The development within the project of perovskite semiconductors with very high luminescence efficiency is important for the efficient operation of both solar cells and also luminescent devices such as LEDs. Patents have been filed to cover aspects of this work. LEDs with close to 100% internal quantum efficiency, in the IR and also green, have been developed. A new company, Helio Display Materials (first registered as Heliochrome) has been founded to exploit light emission from perovskite semiconductors.
First Year Of Impact 2016
Sector Electronics,Energy
Impact Types Economic

 
Title CCDC 1540600: Experimental Crystal Structure Determination 
Description Related Article: Hung-Yang Chen, Mark Nikolka, Andrew Wadsworth, Wan Yue, Ada Onwubiko, Mingfei Xiao, Andrew J. P. White, Derya Baran, Henning Sirringhaus, and Iain McCulloch|2018|Macromolecules|51|71|doi:10.1021/acs.macromol.7b00934 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1nq3s8&sid=DataCite
 
Title CCDC 1590306: Experimental Crystal Structure Determination 
Description Related Article: Hung-Yang Chen, Guillaume Schweicher, Miquel Planells, Sean M. Ryno, Katharina Broch, Andrew J. P. White, Dimitrios Simatos, Mark Little, Cameron Jellett, Samuel J. Cryer, Adam Marks, Michael Hurhangee, Jean-Luc Brédas, Henning Sirringhaus, and Iain McCulloch|2018|Chem.Mater.|30|7587|doi:10.1021/acs.chemmater.8b02757 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1qcv64&sid=DataCite
 
Title CCDC 1590307: Experimental Crystal Structure Determination 
Description Related Article: Hung-Yang Chen, Guillaume Schweicher, Miquel Planells, Sean M. Ryno, Katharina Broch, Andrew J. P. White, Dimitrios Simatos, Mark Little, Cameron Jellett, Samuel J. Cryer, Adam Marks, Michael Hurhangee, Jean-Luc Brédas, Henning Sirringhaus, and Iain McCulloch|2018|Chem.Mater.|30|7587|doi:10.1021/acs.chemmater.8b02757 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1qcv75&sid=DataCite
 
Title CCDC 1590308: Experimental Crystal Structure Determination 
Description Related Article: Hung-Yang Chen, Guillaume Schweicher, Miquel Planells, Sean M. Ryno, Katharina Broch, Andrew J. P. White, Dimitrios Simatos, Mark Little, Cameron Jellett, Samuel J. Cryer, Adam Marks, Michael Hurhangee, Jean-Luc Brédas, Henning Sirringhaus, and Iain McCulloch|2018|Chem.Mater.|30|7587|doi:10.1021/acs.chemmater.8b02757 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1qcv86&sid=DataCite
 
Title CCDC 1845516: Experimental Crystal Structure Determination 
Description Related Article: Guillaume Schweicher, Gabriele D'Avino, Michael T. Ruggiero, David J. Harkin, Katharina Broch, Deepak Venkateshvaran, Guoming Liu, Audrey Richard, Christian Ruzié, Jeff Armstrong, Alan R. Kennedy, Kenneth Shankland, Kazuo Takimiya, Yves H. Geerts, J. Axel Zeitler, Simone Fratini, Henning Sirringhaus|2019|Adv.Mater.|31|1902407|doi:10.1002/adma.201902407 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1zyds3&sid=DataCite
 
Title CCDC 1889754: Experimental Crystal Structure Determination 
Description Related Article: Helen Bristow, Karl J. Thorley, Andrew J. P. White, Andrew Wadsworth, Maxime Babics, Zeinab Hamid, Weimin Zhang, Alexandra F. Paterson, Jan Kosco, Julianna Panidi, Thomas D. Anthopoulos, Iain McCulloch|2019|Adv. Electronic Mater.||1900344|doi:10.1002/aelm.201900344 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc21fftr&sid=DataCite
 
Title CCDC 1889755: Experimental Crystal Structure Determination 
Description Related Article: Helen Bristow, Karl J. Thorley, Andrew J. P. White, Andrew Wadsworth, Maxime Babics, Zeinab Hamid, Weimin Zhang, Alexandra F. Paterson, Jan Kosco, Julianna Panidi, Thomas D. Anthopoulos, Iain McCulloch|2019|Adv. Electronic Mater.||1900344|doi:10.1002/aelm.201900344 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc21ffvs&sid=DataCite
 
Title CCDC 1889756: Experimental Crystal Structure Determination 
Description Related Article: Helen Bristow, Karl J. Thorley, Andrew J. P. White, Andrew Wadsworth, Maxime Babics, Zeinab Hamid, Weimin Zhang, Alexandra F. Paterson, Jan Kosco, Julianna Panidi, Thomas D. Anthopoulos, Iain McCulloch|2019|Adv. Electronic Mater.||1900344|doi:10.1002/aelm.201900344 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc21ffwt&sid=DataCite
 
Title CCDC 2024118: Experimental Crystal Structure Determination 
Description Related Article: Daniel G. Congrave, Bluebell H. Drummond, Victor Gray, Andrew D. Bond, Akshay Rao, Richard H. Friend, Hugo Bronstein|2021|Polym.Chem.|12|1830|doi:10.1039/D1PY00118C 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc25y84k&sid=DataCite
 
Title Data Supporting "Switching between coherent and incoherent singlet fission via solvent-induced symmetry-breaking" 
Description This data set contains all data necessary to generate the figures in the manuscript. Detailed information on how the data was obtained may be found in the open access manuscript which has been deposited in this repository. Figure 1 - structure and general photo physics of the DT-Mes molecule. Figure 2 - determination of the energy levels of DT-Mes and multiple emissive species. Figure 3 - Transient absorption spectroscopy and excited state evolution. Figure 4 - Transient absorption spectroscopy and varying TT/CT balance. Figure 5 - TT and CT action spectra. Figure 6 - switching between coherent and incoherent singlet fission Figure 7 - multidimensional plot of the surfaces participating in the last part of singlet fission. Figure 8 - summary of singlet fission mechanism. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/298098
 
Title Data for "Is the Chemical Strategy for imbuing 'Polyene' Character in Diketopyrrolopyrrole Based Chromophores sufficient for Singlet Fission?" 
Description Powerpoint of figures in publication 'Is the Chemical Strategy for imbuing 'Polyene' Character in Diketopyrrolopyrrole Based Chromophores sufficient for Singlet Fission?' in: The Journal of Physical Chemistry Letters 2017 8 (5), 984-991 (DOI: 10.1021/acs.jpclett.6b02919). Underlying data is embedded in each figure and can be accessed by double-clicking. Alternatively can be accessed in accompanying excel file. 'Chemical Characterization' file contains equivalent data from chemical doping and cyclic voltammetry measurements, using standard procedures. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
URL https://figshare.shef.ac.uk/articles/dataset/Data_for_Is_the_Chemical_Strategy_for_imbuing_Polyene_C...
 
Title Data for "Is the Chemical Strategy for imbuing 'Polyene' Character in Diketopyrrolopyrrole Based Chromophores sufficient for Singlet Fission?" 
Description Powerpoint of figures in publication 'Is the Chemical Strategy for imbuing 'Polyene' Character in Diketopyrrolopyrrole Based Chromophores sufficient for Singlet Fission?' in: The Journal of Physical Chemistry Letters 2017 8 (5), 984-991 (DOI: 10.1021/acs.jpclett.6b02919). Underlying data is embedded in each figure and can be accessed by double-clicking. Alternatively can be accessed in accompanying excel file. 'Chemical Characterization' file contains equivalent data from chemical doping and cyclic voltammetry measurements, using standard procedures. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
URL https://figshare.shef.ac.uk/articles/dataset/Data_for_Is_the_Chemical_Strategy_for_imbuing_Polyene_C...
 
Title Data for 'Excitation Energy Delocalization and Transfer to Guests within MII4L6 Cage Frameworks' 
Description Powerpoints of optical spectroscopy figures in main text and supporting information of publication 'Excitation Energy Delocalization and Transfer to Guests within MII4L6 Cage Frameworks' in: The Journal of the American Chemistry Society 2017(DOI: 10.1021/jacs.7b06709). Underlying data is embedded in each figure and can be accessed by double-clicking. It requires Origin to access. Main text and supporting information figures are presented in separate files. Mass spectrometry data is contained in separate excel file. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
URL https://figshare.shef.ac.uk/articles/dataset/Data_for_Excitation_Energy_Delocalization_and_Transfer_...
 
Title Data for 'Excitation Energy Delocalization and Transfer to Guests within MII4L6 Cage Frameworks' 
Description Powerpoints of optical spectroscopy figures in main text and supporting information of publication 'Excitation Energy Delocalization and Transfer to Guests within MII4L6 Cage Frameworks' in: The Journal of the American Chemistry Society 2017(DOI: 10.1021/jacs.7b06709). Underlying data is embedded in each figure and can be accessed by double-clicking. It requires Origin to access. Main text and supporting information figures are presented in separate files. Mass spectrometry data is contained in separate excel file. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
URL https://figshare.shef.ac.uk/articles/dataset/Data_for_Excitation_Energy_Delocalization_and_Transfer_...
 
Title Data for Microsecond Carrier Lifetimes, Controlled p-Doping, and Enhanced Air Stability in Low-Bandgap Metal Halide Perovskites 
Description All measurements are on low bandgap formamidinium lead-tin iodide metal halide perovskite films (FASn0.5Pb0.5I3) with a small quantity of zinc iodide added to the precursor solution (where x is the molarity of ZnI2 relative to that of FAI in the precursor). 1. shows photoluminescence quantum efficiency measurements when exciting with a 647nm laser. Time correlated single photon counting measurements (a measure of the photoluminescence lifetime) are in 2., when samples were excited by a 635nm pulsed laser. 3. is the decay of the ground state bleach following photo-excitation, as measured in transient absorption spectroscopy (532nm excitation). This data was calibrated to quantity the excitation density within the film as a function of time following photoexcitiation. 4. is the response of perovskite films when fabricated on a bottom gate/bottom contact transistor device, when in the dark and under different levels of white light illumination. 5. shows standard solar cell characterisation for thin absorber layers incorporated into a full solar cell stack. 6. is the percentage change in lattice parameter found from X-ray diffraction measurements of the different films. 7. is the cross section chemical distribution, as measured in scanning transmission electron microscopy energy-dispersive X-ray (STEM-EDX) spectroscopy. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/302205
 
Title Data for: How Exciton Interactions Control Spin-Depolarisation in Layered Hybrid Perovskites 
Description Contains Faraday rotation, Circularly polarised transient absorption, time-resolved photoluminescence and absorption data on the 2D perovskite FAMAPbI7. Also contains pre-review PDF's of manuscript and SI. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/310938
 
Title Data for: Relaxed current matching requirements in highly luminescent perovskite tandem solar cells and their fundamental efficiency limits 
Description Figure 1 contains data for the limiting efficiency of a Shockley-Queisser tandem solar cell, with and without luminescence coupling included in simulations. Figure 2 contains decay data from transient absorption spectroscopy and photoluminescence quantum efficiency measurements for the halide perovskite thin film FA0.7Cs0.3Pb(I0.7Br0.3)3. It also contains absorption coefficient and (real) refractive index for both FA0.7Cs0.3Pb(I0.7Br0.3)3 and FAPb0.5Sn0.5I3 thin films, as measured by a combination of ellipsometry, photothermal deflection spectroscopy and Ubach tail fitting. Figure 3 contans the absorbance of FAPb0.5Sn0.5I3 in an idealised tandem stack with FA0.7Cs0.3Pb(I0.7Br0.3)3, the limiting efficiency of this stack as a function of thickness without and with luminescence coupling included in simulations, and the difference in power generated throughout the year without and with luminescence coupling for a typical spectral year on the Canada/USA border from these modelled solar cells. Figure 4 contains the limiting efficiency of the all-perovskite tandem as a function of charge trapping rate (for optimised thicknesses) with luminescence coupling, and a ratio of this result to a second simulation including luminescnece coupling. Figure 5 explores an experimental all-perovskite tandem solar cell. It contains the photoluminescence emission (relative to that at open-circuit voltage) of the high-bandgap sub-cell as a function of applied voltage when illuminated by a 405nm laser, the microscopic photoluminescence from a cross section of the tandem when excited by a 636nm laser, the photolumiescence from a cross section of this region when only the high-bandgap sub-cell is excited, and the time resolve photoluminescence of this emission. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/316458
 
Title Data supporting "Graphene-passivated nickel as an efficient hole-injecting electrode for large area organic semiconductor devices" 
Description Figure 1: (d) Raman spectrum of few-layer graphene on Ni. (e) XPS of Ni 2p3/2 region of sputtered Ni (Ni/NiOx) and Ni after multilayer graphene growth (Ni/FLG), with peak fitting indicating metallic nickel (NiM) and nickel oxide (NiOx). (f) Magnetic moment measured at room temperature by DC-mode SQUID magnetometry of graphene-passivated Ni films for magnetic fields parallel and perpendicular to the plane of the film. Figure 2: (b) Comparison of hole injection into F8BT from graphene-passivated Ni and PEDOT:PSS bottom contacts, each using a top contact of MoO3 / Au. (c) Binding energy, referenced to the Fermi level, measured on a Ni/FLG sample by means of UPS (excitation light with energy = 21.21 eV). (d) Hole injection into P3HT from graphene-passivated Ni, with MoO3 /Au top contact. Figure 3: Current density hysteresis as a function of voltage for hole injection into F8BT using (a) unprotected sputtered Ni electrodes and (b) graphene-passivated Ni. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/306104
 
Title Data supporting "Star-shaped fluorene-BODIPY oligomers: versatile donor-acceptor systems for luminescent solar concentrators" 
Description Data files behind figures in this publication 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/262045
 
Title Data supporting "The Role of Photon Recycling in Perovskite Light-Emitting Diodes" 
Description  
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/300135
 
Title Perovskite/Colloidal Quantum Dot Tandem Solar Cells: Theoretical Modeling and Monolithic Structure 
Description © 2018 American Chemical Society. Metal-halide perovskite-based tandem solar cells show great promise for overcoming the Shockley-Queisser single-junction efficiency limit via low-cost tandem structures, but so far, they employ conventional bottom-cell materials that require stringent processing conditions. Meanwhile, difficulty in achieving low-bandgap (<1.1 eV) perovskites limits all-perovskite tandem cell development. Here we propose a tandem cell design based on a halide perovskite top cell and a chalcogenide colloidal quantum dot (CQD) bottom cell, where both materials provide bandgap tunability and solution processability. A theoretical efficiency of 43% is calculated for tandem-cell bandgap combinations of 1.55 (perovskite) and 1.0 eV (CQDs) under 1-sun illumination. We highlight that intersubcell radiative coupling contributes significantly (>11% absolute gain) to the ultimate efficiency via photon recycling. We report an initial experimental demonstration of a solution-processed monolithic perovskite/CQD tandem solar cell, showing evidence for subcell voltage addition. We model that a power conversion efficiency of 29.7% is possible by combining state-of-the-art perovskite and CQD solar cells. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Research Data Supporting "Efficient Vacuum-Processed Light-Emitting Diodes Based on Carbene-Metal-Amides" 
Description Research Data Supporting "Efficient Vacuum-Processed Light-Emitting Diodes Based on Carbene-Metal-Amides" 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/278463
 
Title Research Data Supporting Visualising Performance-Limiting Nanoscale Trap Clusters at Grain Junctions in Halide Perovskites 
Description This repository contains data necessary to reproduce figures and results from the associated manuscript. Files included contain data from scanning electron diffraction , photo emission electron microscopy, scanning transmission electron microscopy - energy dispersive X-ray spectroscopy, Kelvin probe force microscopy and photoluminescence measurements. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/304634
 
Title Research Data Supporting: 'Spontaneous exciton dissociation enables spin state interconversion in delayed fluorescence organic semiconductors' 
Description Zip folder containing the data that forms the figures in the main text of the publication. The Microsoft Excel file contains the transient absorption spectra and related kinetics for the neat BF2 and dilution series in CBP films, presented in wavelength (nm) and time (picoseconds), respectively. Also included in the Excel file are the photoluminescence-detected magnetic resonance spectra for the neat BF2 film, taken at different applied microwave magnetic field strengths (B1). The photoluminescence-detected magnetic resonance spectra are presented in magnetic field strength, B0 (mT). See the main manuscript for more details. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/330185
 
Title Research Data supporting ''Insights into the Degradation Mechanism of Carbene-Metal-Amide Organic Light-Emitting Diodes" 
Description Data is provided in a single .xlsx file and contains multiple sheets. Each sheet is titled with the experiment in question and columns are headed with the type of data and units for that column. "EL Intensity vs Time" contains data relating to the electroluminescence from CMA1 based OLEDs operated at various current densities, normalised to the initial brightness. The time taken to drop to 50% of the initial brightness is then listed in "EL LT50" "Electron-only device PL" and "Hole-only device PL" contains data of the normalised photoluminescence intensity from unipolar devices under photoexcitation, application of an electrical current and both simultaneously. "Fraction of red emission" contains data of the fraction of the electroluminescence originating from DCJTB vs CMA1 in OLEDs. Data is provided for different current densities and for each sensitised device where device 1 has the sensitising strip at the TAPC/CMA1 interface and device 8 has the sensitising strip at the CMA1/UGH2 interface. "PL intensity vs time" contains data of the photoluminescence intensity of CMA1 thin films excited at different power densities. The data is normalised to the initial intensity and the time taken to drop to 85% is given in "PL LT85". "V, J, L, EQE of OLEDs" contains data of the voltage/current density, luminance and external quantum efficiency of CMA1 OLEDs. The electroluminescence spectrum of these OLEDs is provided in " EL spectrum of OLEDs" "JV of unipolar devices" contains data of the voltage-current density relationship of the unipolar devices. "JV of sensitized devices contains data of the voltage-current density relationship of the sensitized devices. "PL intensity vs power" contains data of the photoluminescence intensity of CMA1 at different excitation densities. "CMA1 absorption" provides the optical absorption of a CMA1 film. Further information on the experimental methods used to acquire this data is provided in the supplementary information file available from the article publishers. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/340574
 
Title Research Data supporting: "Thermalization and relaxation mediated by phonon management in tin-lead perovskites" 
Description Data and images underlying Figures 1-6 in the paper, including TEM images and transient absorption data. See .docx file for further details. Abstract of associated publication: Understanding and control of ultrafast non-equilibrium processes in semiconductors is key to making use of the full photon energy before relaxation, leading to new ways to break efficiency limits for solar energy conversion. In this work, we demonstrate the observation and modulation of slow relaxation in uniformly mixed tin-lead perovskites (MASnxPb1-xI3 and CsSnxPb1-xI3 nanocrystals). Transient absorption measurements reveal that slow cooling mediated by a hot phonon bottleneck effect appears at carrier densities above ~1018 cm-3 for tin-lead alloy nanocrystals, and tin addition is found to give rise to suppressed cooling. Within the alloy nanoparticles, the combination of a newly introduced high-energy band, screened Fröhlich interaction, suppressed Klemens decay and reduced thermal conductivity (acoustic phonon transport) with increased tin content contributes to the slowed relaxation. For inorganic nanocrystals where defect states couple strongly with carriers, sodium doping has been confirmed to benefit in maintaining hot carriers by decoupling them from deep defects, leading to a decreased energy-loss rate during thermalization and an enhanced hot phonon bottleneck effect. The slow cooling we observe uncovers the intrinsic photophysics of perovskite nanocrystals, with implications for photovoltaic applications where suppressed cooling could lead to hot-carrier solar cells. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/358684
 
Title Research data supporting "Charge Generation and Electron Trapping Dynamics in Hybrid Nanocrystal-Polymer Solar Cells " 
Description Data files for each of the figures in the main publication and the supplementary information. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/256983
 
Title Research data supporting "Chasing the "Killer" Phonon Mode for the Rational Design of Low-Disorder, High-Mobility Molecular Semiconductors" 
Description - Figure 1: OFET IV Curves and TLM - Figure 2: INS and THz data - Figure 3 & 4: 1. Phonon mode index 2. Frequency in the harmonic approximation (HO) 3. Frequency beyond the HO (only few modes were corrected for ahnarmonic effects) 4-5. Standard deviation of site energies (in meV) 6-9. Standard deviation of transfer integrals (in meV) 10. Standard deviation of vibrational coordinates transfer integrals (in Angstrom) Figure 5: Transient Localization Scenario mobility values 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/297493
 
Title Research data supporting "Decoupling Charge Transport and Electroluminescence in a High Mobility Polymer Semiconductor" 
Description An origin file containing data used for the publication Decoupling Charge Transport and Electroluminescence in a High Mobility Polymer Semiconductor. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/254913
 
Title Research data supporting "Dedoping of Lead Halide Perovskites Incorporating Monovalent Cations" 
Description Raw data files pertaining to the materials characterization, DFT calculations and solar cell measurements. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Research data supporting "Efficient singlet exciton fission in pentacene prepared from a soluble precursor" 
Description Underlying datasets for all figures in the Manuscript and the SI. Data comprises results from absorption-, photoluminescence-, ellipsometry-, transient spectroscopy-, FTIR-, X-ray and atomic force microscopy measurements. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
 
Title Research data supporting "Efficient singlet fission and triplet-pair emission in a family of zethrene diradicaloids" 
Description Data files underlying figures in paper 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/270486
 
Title Research data supporting "Environmental Control of Triplet Emission in Donor-Bridge-Acceptor Organometallics" 
Description  
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/299266
 
Title Research data supporting "Exciton-Phonon Interactions Govern Charge-Transfer-State Dynamics in CdSe/CdTe Two-Dimensional Colloidal Heterostructures" 
Description The dataset contains the raw data associated with Figures 1-2 and Figure 4-6. The data in Figure 3 is derived from the raw data in Figure 2 as explained in the text. The data in Figure 7 is derived from Figure 5 using the fitting as explained in the main text. The raw data includes the the femotsecond pump probe data and associated FFT maps, absoprtion and photoluminsence spectra, PDS data and raw data associated with cryogenic PL measurements, Raman data and TCSPC data. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/354014
 
Title Research data supporting "High Circular Polarization of Electroluminescence Achieved via Self-Assembly of a Light-Emitting Chiral Conjugated Polymer into Multidomain Cholesteric Films" 
Description Left and right-handed circularly polarized components of Electro-Luminescence and corresponding dissymmetry factors. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Research data supporting "High-efficiency perovskite-polymer bulk heterostructure light-emitting diodes" 
Description Datasets for figures in "High-efficiency perovskite-polymer bulk heterostructure light-emitting diodes" 
Type Of Material Database/Collection of data 
Provided To Others? Yes  
 
Title Research data supporting "High-performance light-emitting diodes based on carbene-metal-amides" 
Description This dataset includes the experimental results of optical spectroscopy (cryogenic transient photoluminescence, transient absorption, ultrafast transient photoluminescence, transient electroluminescence, steady-state emission/absorption and Raman), OLED device characterization, electrochemistry, as well as data associated with quantum chemical (DFT) calculations. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
 
Title Research data supporting "Highly-Efficient Perovskite Nanocrystal Light-Emitting Diodes Enabled by a Universal Cross-linking Method" 
Description The data corresponds to the images in the paper, the user need to have a power point and an origin software, and then open the data by clicking the images in the powerpoint. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/253968
 
Title Research data supporting "Improving the photoluminescence quantum yields of quantum dot films through a donor/acceptor system for near-IR LEDs" 
Description Data underlying each Figure in the paper, namely absorption spectra, emission spectra, transient absorption data and LED characteristics for mixed quantum dot films. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Research data supporting "Lead Telluride Quantum Dot Solar Cells Displaying External Quantum Efficiencies Exceeding 120%" 
Description The data is the basis for all Figures in the manuscript and Supporting Information. 
Type Of Material Database/Collection of data 
Year Produced 2015 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/252376
 
Title Research data supporting "Maximizing and stabilizing luminescence from halide perovskites with potassium passivation" 
Description The raw data for the published photoluminescence quantum efficiency (PLQE) results in "Maximizing and stabilizing luminescence from halide perovskites with potassium passivation". 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/348943
 
Title Research data supporting "Singlet Exciton Fission in a Modified Acene with Improved Stability and High Photoluminescence Yield" 
Description This dataset summarises the photophysical characterisation of TTBP and includes all of the data in the figures of the main text of the manuscript. Each data set is entitled with figure name in article i.e. Fig2a contains raw data and Figure 2a in the main article. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/316456
 
Title Research data supporting "Site-selective measurement of coupled spin pairs in an organic semiconductor" 
Description Numerical data underlying each of the Figures in the associated publication. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/275231
 
Title Research data supporting "Synthesis and Optical Properties of Lead-Free Cesium Tin Halide Perovskite Nanocrystals" 
Description The uploaded data is the basis for all figures presented in the manuscript and the Supporting Information 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/254023
 
Title Research data supporting "Tuning the Role of Charge-Transfer States in Intramolecular Singlet Exciton Fission Through Side-Group Engineering" 
Description Transient absorption spectroscopy data (Cavendish Lab, Cambridge) collected between 01/2014 and 01/2016 Picosecond transient photoluminescence spectroscopy data (Cavendish Lab, Cambridge) collected between 01/2014 and 01/2016 Femtosecond transient photoluminescence spectroscopy data (MacDiarmid Institute of Advanced Materials and Nanotechnology, New Zealand) collected between 06/2014 and 06/2015 Electronic structure calculation (Cavendish Lab, Cambridge) 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/260779
 
Title Research data supporting "Vertical Cavity Biexciton Lasing in 2-Dimensional Dodecylammonium Lead Iodide Perovskites" 
Description Origin files underlying Figures in the paper and SI 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/278609
 
Title Research data supporting "Vibrationally Assisted Intersystem Crossing in Benchmark Thermally Activated Delayed Fluorescence Molecules" 
Description Raw data for manuscript titled 'Vibrationally-assisted intersystem crossing in benchmark thermally activated delayed fluorescence molecules.' Data includes absorption and photoluminescence spectra for 2CzPN and 4CzIPN (Fig1b_Abs_2CzPN, Fig1b_Abs_4CzIPN, Fig1b_PL_2CzPN, Fig1b_PL_4CzIPN); transient electron spin resonance spectra for 2CzPN and 4CzIPN (Fig2c_2CzPN_0p4us, Fig2d_4CzIPN_0p4us); probability distributions for zero-field splitting in 2CzPN and 4CzIPN (Fig3a_2CzPN_ZFS_probability_distribution, Fig3b_4CzIPN_ZFS_probability_distribution); plots of zero-field splitting as a function of overlap index in 2CzPN and 4CzIPN (Fig3c_2CzPN_ZFS_overlap_idx, Fig3d_4CzIPN_ZFS_overlap_idx); and density plots (field versus time) of transient electron spin resonance spectra of 2CzPN and 4CzIPN (FigS1_TrESR_2CzPN_420nm_exc, FigS1_TrESR_4CzIPN_460nm_exc). 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/277932
 
Title Research data supporting Lead-Free Perovskite Semiconductors Based on Germanium-Tin Solid Solutions: Structural and Optoelectronic Properties 
Description The data has been collected from multiple instruments including XRD, PL, PDS and simulations. The details of which are mentioned in the linked manuscript. 
Type Of Material Database/Collection of data 
Provided To Others? Yes  
 
Title Research data supporting Optical and electronic properties of colloidal CdSe quantum rings 
Description Raw data underlying publication. Includes femtosecond transient absorption maps, picosecond transient absorption maps, absorption and emission data. The pump-probe data was generated using a custom setup as detailed in the methods of the paper. The data was processed and analysed used a custom matlab program and then plotted in Origin to generate the figures. The absorption and emission data are generated from measurement techniques described in the methods section of the paper using comercial instruments. The raw data is processed and plotted in the Origin graphing program. The data set contains all the raw data associated with these figures, including appropriate column designations. The data submitted is raw and unprocessed. Analysis methods are shown and can be obtained in the main text. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/315791
 
Title Research data supporting: "Ultrafast carrier thermalization in lead iodide perovskite probed with two-dimensional electronic spectroscopy" 
Description Research data supportingthe findings of the manuscript "Ultrafast carrier thermalization in lead iodide perovskite probed with two-dimensional electronic spectroscopy". All data is provided in form of embedded Origin graphs in a PPT file. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
 
Title Research data supporting: Dielectric control of reverse intersystem crossing in thermally activated delayed fluorescence emitters 
Description A Microsoft Excel file containing the data that forms the figures in the main text of the publication. The Microsoft Excel file contains the ultrafast transient absorption and photoluminescence data for TXO-TPA and 4CzIPN, presented in wavelength (nm) and time (ps). Also included is the steady state Raman and impulsive vibrational spectra of TXO-TPA and 4CzIPN at 0.5, 3, and 10 ps (in wavenumbers). The full datasets for the quantum-chemical molecular dynamics simulations of TXO-TPA are also presented. See the main manuscript for more details. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/339315
 
Company Name Helio Display Materials 
Description Helio Display Materials develops a range of optoelectronic devices, featuring light emitting perovskites. 
Year Established 2016 
Impact Heliochrome is developing new materials and LEDs based on published and patented discoveries at the Universities of Oxford and Cambridge
Website http://www.heliodisplaymaterials.com