Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

This article is written from an organic chemist's point of view and provides an up-to-date review about organic solar cells based on small molecules or oligomers as absorbers and in detail deals with devices that incorporate planar-heterojunctions (PHJ) and bulk heterojunctions (BHJ) between a donor (p-type semiconductor) and an acceptor (n-type semiconductor) material. The article pays particular attention to the design and development of molecular materials and their performance in corresponding devices. In recent years, a substantial amount of both, academic and industrial research, has been directed towards organic solar cells, in an effort to develop new materials and to improve their tunability, processability, power conversion efficiency, and stability. On the eve of commercialization of organic solar cells, this review provides an overview over efficiencies attained with small molecules/oligomers in OSCs and reflects materials and device concepts developed over the last decade. Approaches to enhancing the efficiency of organic solar cells are analyzed.

Small molecule organic semiconductors on the move: promises for future solar energy technology.

Organic photovoltaic cells (OPVs) are a promising cost-effective alternative to silicon-based solar cells, and possess light-weight, low-cost, and flexibility advantages. Significant progress has been achieved in the development of novel photovoltaic materials and device structures in the last decade. Nowadays small molecular semiconductors for OPVs have attracted considerable attention, due to their advantages over their polymer counterparts, including well-defined molecular structure, definite molecular weight, and high purity without batch to batch variations. The highest power conversion efficiencies of OPVs based on small molecular donor/fullerene acceptors or polymeric donor/fullerene acceptors are up to 6.7% and 8.3%, respectively, and meanwhile nonfullerene acceptors have also exhibited some promising results. In this review we summarize the developments in small molecular donors, acceptors (fullerene derivatives and nonfullerene molecules), and donor–acceptor dyad systems for high-performance multilayer, bulk heterojunction, and single-component OPVs. We focus on correlations of molecular chemical structures with properties, such as absorption, energy levels, charge mobilities, and photovoltaic performances. This structure–property relationship analysis may guide rational structural design and evaluation of photovoltaic materials (253 references).

Small molecule semiconductors for high-efficiency organic photovoltaics

Cyclodextrins have been used as a cyclic component in the construction of supramolecular architectures. Recently they have been studied as a component in the construction of rotaxanes and catenanes. A cyclodextrin ring can translocate in some rotaxane and catenane structures. Therefore, much attention has been given to cyclodextrins as a component of molecular shuttles, motors, and machines. Attempts to design and synthesize molecular-level machines using cyclodextrins as a cyclic component are described.

Cyclodextrin-based molecular machines.

Although most research in the field of organic bulk heterojunction solar cells has focused on combinations of a p-type conducting polymer as a donor and a fullerene-based acceptor, recent work has demonstrated the viability of solution-processed heterojunctions composed entirely of molecular solids. Molecular solids offer potential advantages over conjugated polymer systems in terms of easier purification, amenability to mass-scale production and better batch-to-batch reproducibility. This article reviews the major classes of molecular donors that have been reported in the literature in the past several years and highlights some of key considerations in molecular heterojunction design compared to polymer-based bulk heterojunctions.

Small Molecule Solution-Processed Bulk Heterojunction Solar Cells†

Electrically conductive polymeric materials have recently attracted considerable interest from academic and industrial researchers to explore their potential in biomedical applications such as in biosensors, drug delivery systems, biomedical implants and tissue engineering. Conventional conductive homopolymers such as polypyrrole and PEDOT show promising conductivity for these applications, however their mechanical properties, biocompatibility and processability are often poor. This has led to more recent attention being directed towards conductive polymeric composites comprised of biostable/biocompatible polymers with dispersed conductive fillers such as graphene, carbon nanotubes and metallic nanoparticles. The major objective of this paper is to provide an up to date review of the recent investigations conducted in the development of conductive polymer composites focussing on the methods of their preparation, underlying concepts of their conductivity and the ways to tailor their properties. Furthermore, recent progress made in conventional conducting polymers and their composites/blends for biomedical applications is also discussed.

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Electrically conductive polymers and composites for biomedical applications

The significant and rapid reduction of greenhouse gas emissions is recognized as necessary to mitigate the potential climate effects from global warming. The postcombustion capture (PCC) and storage of carbon dioxide (CO2) produced from the use of fossil fuels for electricity generation is a key technology needed to achieve these reductions. The most mature technology for CO2 capture is reversible chemical absorption into an aqueous amine solution. In this study the results from measurements of the CO2 absorption capacity of aqueous amine solutions for 76 different amines are presented. Measurements were made using both a novel isothermal gravimetric analysis (IGA) method and a traditional absorption apparatus. Seven amines, consisting of one primary, three secondary, and three tertiary amines, were identified as exhibiting outstanding absorption capacities. Most have a number of structural features in common including steric hindrance and hydroxyl functionality 2 or 3 carbons from the nitrogen. Initial CO2 absorption rate data from the IGA measurements was also used to indicate relative absorption rates. Most of the outstanding performers in terms of capacity also showed initial absorption rates comparable to the industry standard monoethanolamine (MEA). This indicates, in terms of both absorption capacity and kinetics, that they are promising candidates for further investigation.

Carbon dioxide postcombustion capture: a novel screening study of the carbon dioxide absorption performance of 76 amines

Soluble, electroactive derivatives based upon dibenzo[b,def]chrysene are introduced. These compounds do not chemically react with fullerenes, enabling the preparation of solution-processed solar cells based on small molecule blends. Device power conversion efficiencies of 2.25% are described and a correlation between processing conditions, film morphology, and device efficiencies is demonstrated.

Dibenzo[b,def]chrysene Derivatives: Solution-Processable Small Molecules that Deliver High Power-Conversion Efficiencies in Bulk Heterojunction Solar Cells

Polylactide (PLA) is the leading bioderived polymer produced commercially by the metal-catalyzed ring-opening polymerization of lactide. Control over tacticity to produce stereoblock PLA, from rac-lactide improves thermal properties but is an outstanding challenge. Here, phosphasalen indium catalysts feature high rates (30±3 m−1 min−1, THF, 298 K), high control, low loadings (0.2 mol %), and isoselectivity (Pi=0.92, THF, 258 K). Furthermore, the phosphasalen indium catalysts do not require any chiral additives.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.201701745

Mark Bown

Papers

Electrically conductive polymers and composites for biomedical applications

Carbon dioxide postcombustion capture: a novel screening study of the carbon dioxide absorption performance of 76 amines

Dibenzo[b,def]chrysene Derivatives: Solution-Processable Small Molecules that Deliver High Power-Conversion Efficiencies in Bulk Heterojunction Solar Cells

Phosphasalen Indium Complexes Showing High Rates and Isoselectivities in rac-Lactide Polymerizations

The structure of FcCu2Al7 and T(CoCuAl)