Sarah Holliday

Imperial College London

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Iain McCulloch

University of Oxford

Christian B. Nielsen

Queen Mary University of London

James R. Durrant

Imperial College London

Andrew Wadsworth

University of Oxford

Derya Baran

King Abdullah University of Science and Technology

Raja Shahid Ashraf

Government College University, Lahore

Nicola Gasparini

Imperial College London

Stoichko D. Dimitrov

Queen Mary University of London

Christoph J. Brabec

Friedrich-Alexander-Universität Erlangen-Nürnberg

Ching‐Hong Tan

South China University of Technology

Cooperative Institutions

Imperial College London

Transnational Press London

King Abdullah University of Science and Technology

University of Oxford

Plastic Electronics (Netherlands)

University of Washington

Stanford University

Friedrich-Alexander-Universität Erlangen-Nürnberg

University of Cambridge

Seattle University

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Introduction

Springer theses (2018)

Sarah Holliday

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10.1007/978-3-319-77091-8_1

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Citations (1)

Efficient truxenone-based acceptors for organic photovoltaics

Journal of Materials Chemistry A (2012)

Christian B. Nielsen Eszter Vörösházi Sarah Holliday Kjell Cnops Barry P. Rand

Two electron-deficient truxenone derivatives are designed and synthesised for organic photovoltaic applications. The promise of this class of compounds as acceptor materials is illustrated by the fabrication of efficient bilayer solar cells with a subphthalocyanine (SubPc) donor, clearly outperforming reference cells with a soluble fullerene derivative as the acceptor.

Acceptor

Electron acceptor

Derivative (finance)

10.1039/c2ta00548d

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Citations (49)

Excitation Wavelength-Dependent Internal Quantum Efficiencies in a P3HT/Nonfullerene Acceptor Solar Cell

The Journal of Physical Chemistry C (2018)

Ching‐Hong Tan Andrew Wadsworth Nicola Gasparini Scot Wheeler Sarah Holliday

Solar cells based on blends of the donor polymer, P3HT, with the nonfullerene acceptor, O-IDTBR, have been shown to exhibit promising efficiencies and stabilities for low-cost organic photovoltaic devices. We focus herein on the charge separation and recombination dynamics in such devices. By employing selective wavelength excitations of P3HT and O-IDTBR, we show that photoexcitation of P3HT results in lower internal quantum efficiency (IQE) for photocurrent generation than that observed for photoexcitation of O-IDTBR. Transient absorption and photoluminescence quenching studies indicate that this lower IQE results primarily from higher geminate recombination losses of photogenerated charges following P3HT excitation compared with O-IDTBR excitation, rather than from differences in exciton separation efficiency. These higher geminate recombination losses result in lower photocurrent generation efficiency at short circuit upon selective excitation of the P3HT donor, when compared with O-IDTBR excitation.

Photoexcitation

Photocurrent

Quantum Efficiency

Acceptor

10.1021/acs.jpcc.8b10918

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Citations (7)

Truxenone Based Acceptors

Springer theses (2018)

Sarah Holliday

10.1007/978-3-319-77091-8_2

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Influence of Polymer Aggregation and Liquid Immiscibility on Morphology Tuning by Varying Composition in PffBT4T‐2DT/Nonfullerene Organic Solar Cells

Advanced Energy Materials (2020)

Zeinab Hamid Andrew Wadsworth Elham Rezasoltani Sarah Holliday Mohammed Azzouzi

Abstract The temperature‐dependent aggregation behavior of PffBT4T polymers used in organic solar cells plays a critical role in the formation of a favorable morphology in fullerene‐based devices. However, there is little investigation into the impact of donor/acceptor ratio on morphology tuning, especially for nonfullerene acceptors (NFAs). Herein, the influence of composition on morphology is reported for blends of PffBT4T‐2DT with two NFAs, O‐IDTBR and O‐IDFBR. The monotectic phase behavior inferred from differential scanning calorimetry provides qualitative insight into the interplay between solid–liquid and liquid–liquid demixing. Transient absorption spectroscopy suggests that geminate recombination dominates charge decay and that the decay rate is insensitive to composition, corroborated by negligible changes in open‐circuit voltage. Exciton lifetimes are also insensitive to composition, which is attributed to the signal being dominated by acceptor excitons which are formed and decay in domains of similar size and purity irrespective of composition. A hierarchical morphology is observed, where the composition dependence of size scales and scattering intensity from resonant soft X‐ray scattering (R‐SoXS) is dominated by variations in volume fractions of polymer/polymer‐rich domains. Results suggest an optimal morphology where polymer crystallite size and connectivity are balanced, ensuring a high probability of hole extraction via such domains.

Acceptor

Morphology

10.1002/aenm.201903248

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Citations (27)

The effect of fluorination on the surface structure of truxenones

RSC Advances (2016)

Luke A. Rochford Alexandra J. Ramadan Sarah Holliday T. S. Jones Christian B. Nielsen

The surface structure of partially fluorinated truxenone (F₃-truxenone) molecules on Cu (111) has been probed using a combination of scanning tunneling microscopy (STM) and low energy electron diffraction (LEED).

10.1039/c6ra14158g

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Citations (2)

Truxenone-based small molecule acceptors for efficient organic photovoltaic devices

B. Christian Nielsen Eszter Vörösházi Kjell Cnops Sarah Holliday Barry P. Rand

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Organic/inorganic epitaxy: commensurate epitaxial growth of truxenone on Cu (111)

Figshare (2016)

Alexandra J. Ramadan Christian B. Nielsen Sarah Holliday Tim S. Jones Iain McCulloch

The growth of monolayers of truxenone on Cu (111) is investigated using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Two distinct molecular packing motifs are observed which exist individually at low and high coverage, and coexist at intermediate states. In each case a commensurate epitaxial relationship between the molecular surface mesh and the substrate is observed.

10.6084/m9.figshare.2074360

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A Rhodanine Flanked Nonfullerene Acceptor for Solution-Processed Organic Photovoltaics

Journal of the American Chemical Society (2014)

Sarah Holliday Raja Shahid Ashraf Christian B. Nielsen Mindaugas Kirkus Jason A. Rӧhr

A novel small molecule, FBR, bearing 3-ethylrhodanine flanking groups was synthesized as a nonfullerene electron acceptor for solution-processed bulk heterojunction organic photovoltaics (OPV). A straightforward synthesis route was employed, offering the potential for large scale preparation of this material. Inverted OPV devices employing poly(3-hexylthiophene) (P3HT) as the donor polymer and FBR as the acceptor gave power conversion efficiencies (PCE) up to 4.1%. Transient and steady state optical spectroscopies indicated efficient, ultrafast charge generation and efficient photocurrent generation from both donor and acceptor. Ultrafast transient absorption spectroscopy was used to investigate polaron generation efficiency as well as recombination dynamics. It was determined that the P3HT:FBR blend is highly intermixed, leading to increased charge generation relative to comparative devices with P3HT:PC60BM, but also faster recombination due to a nonideal morphology in which, in contrast to P3HT:PC60BM devices, the acceptor does not aggregate enough to create appropriate percolation pathways that prevent fast nongeminate recombination. Despite this nonoptimal morphology the P3HT:FBR devices exhibit better performance than P3HT:PC60BM devices, used as control, demonstrating that this acceptor shows great promise for further optimization.

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Electron acceptor

Electron donor

10.1021/ja5110602

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Citations (454)

High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor

Nature Communications (2016)

Sarah Holliday Raja Shahid Ashraf Andrew Wadsworth Derya Baran Syeda Amber Yousaf

Abstract Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which themselves have issues with cost, stability and limited spectral absorption. Here we present a new non-fullerene acceptor that has been specifically designed to give improved performance alongside the wide bandgap donor poly(3-hexylthiophene), a polymer with significantly better prospects for commercial OPV due to its relative scalability and stability. Thanks to the well-matched optoelectronic and morphological properties of these materials, efficiencies of 6.4% are achieved which is the highest reported for fullerene-free P3HT devices. In addition, dramatically improved air stability is demonstrated relative to other high-efficiency OPV, showing the excellent potential of this new material combination for future technological applications.

Acceptor

10.1038/ncomms11585

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Citations (1,114)