Suchergebnisse

The porosity of filters is typically fixed; thus, complex purification processes require application of multiple specialized filters. In contrast, smart filters with controllable and tunable properties enable dynamic separation in a single setup. Herein, an electroactive filter with controllable pore size is demonstrated. The electroactive filter is based on a metal mesh coated with a polythiophene polymer with ethylene glycol sidechains (p(g3T2)) that exhibit unprecedented voltage-driven volume changes. By optimizing the polymer coating on the mesh, controllable porosity during electrochemical addressing is achieved. The pores reversibly open and close, with a dynamic range of more than 95%, corresponding to over 30 mu m change of pores widths. Furthermore, the pores widths could be defined by applied potential with a 10 mu m resolution. From among hundreds of pores from different samples, about 90% of the pores could be closed completely, while only less than 1% are inactive. Finally, the electroactive filter is used to control the flow of a dye, highlighting the potential for flow control and smart filtration applications. ; Funding Agencies|Wallenberg Wood Science Center [KAW 2018.0452]; Swedish Research Council - VetenskapsradetSwedish Research Council [VR-2020-05045]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; KAUSTKing Abdullah University of Science & Technology; EPSRCUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) [EP/T026219/1]; European UnionEuropean Commission [952911, 862474, 101007084]

The porosity offilters is typicallyfixed; thus, complex purification processesrequire application of multiple specializedfilters. In contrast, smartfilters withcontrollable and tunable properties enable dynamic separation in a single setup.Herein, an electroactivefilter with controllable pore size is demonstrated. Theelectroactivefilter is based on a metal mesh coated with a polythiophene polymerwith ethylene glycol sidechains (p(g3T2)) that exhibit unprecedented voltage-driven volume changes. By optimizing the polymer coating on the mesh, con-trollable porosity during electrochemical addressing is achieved. The poresreversibly open and close, with a dynamic range of more than 95%, corre-sponding to over 30μm change of pores'widths. Furthermore, the pores'widthscould be defined by applied potential with a 10μm resolution. From amonghundreds of pores from different samples, about 90% of the pores could beclosed completely, while only less than 1% are inactive. Finally, the electroactivefilter is used to control theflow of a dye, highlighting the potential forflow controland smartfiltration applications. ; J.G. and V.K.O contributed equally to this work. This work was supported by The Wallenberg Wood Science Center (KAW 2018.0452), the Swedish Research Council—Vetenskapsrådet—VR-2020-05045, the Knut and Alice Wallenberg Foundation, and the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). We also acknowledge financial support from KAUST, as well as from the European Union's Horizon 2020 research and innovation programme under grant agreement No.952911, project BOOSTER grant agreement No.862474, project RoLA-FLEX, grant agreement No.101007084, project CITYSOLAR as well as EPSRC Project EP/T026219/1

Conjugated polymers exhibit electrically driven volume changes when included in electrochemical devices via the exchange of ions and solvent. So far, this volumetric change is limited to 40% and 100% for reversible and irreversible systems, respectively, thus restricting potential applications of this technology. A conjugated polymer that reversibly expands by about 300% upon addressing, relative to its previous contracted state, while the first irreversible actuation can achieve values ranging from 1000–10 000%, depending on the voltage applied is reported. From experimental and theoretical studies, it is found that this large and reversible volumetric switching is due to reorganization of the polymer during swelling as it transforms between a solid-state phase and a gel, while maintaining percolation for conductivity. The polymer is utilized as an electroactive cladding to reduce the void sizes of a porous carbon filter electrode by 85%. ; J.G. and E.S. contributed equally to this work. M.B. and E.S. conceived the project. J.G. and E.S. performed the experiments and analyzed all data. S.G. and I.Z. performed and analyzed MD calculations. A.G. and M.M. synthesized materials. E.S., M.B., I.Z., and J.G. wrote the manuscript with input from all authors. E.S., M.B., I.Z., and I.M. supervised the project. This work was supported by Knut and Alice Wallenberg Foundation, The Wallenberg Wood Science Center (KAW 2018.0452), the Swedish Research Council (VR), and the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at NSC and HPC2N. A.G. and I.M. acknowledge funding from the Engineering and Physical Sciences Research Council (EP/G037515/1) and (EP/N509486/1).

In living organisms, sensory and motor processes are distributed, locally merged, and capable of forming dynamic sensorimotor associations. We introduce a simple and efficient organic neuromorphic circuit for local sensorimo-tor merging and processing on a robot that is placed in a maze. While the robot is exposed to external environ-mental stimuli, visuomotor associations are formed on the adaptable neuromorphic circuit. With this on-chip sensorimotor integration, the robot learns to follow a path to the exit of a maze, while being guided by visually indicated paths. The ease of processability of organic neuromorphic electronics and their unconventional form factors, in combination with education-purpose robotics, showcase a promising approach of an affordable, versatile, and readily accessible platform for exploring, designing, and evaluating behavioral intelligence through decen-tralized sensorimotor integration. ; We acknowledge F. Keller, A. Steinmetz, and A. Becker from the Max Planck Institute for Polymer Research (MPIP) for significant contribution in the design and realization of the experimental setup (maze, 3D-printed parts, and video recording) and electronics (customization of the robot and additional hardware for conditioning). We also acknowledge H.-J. Guttmann and C. Bauer for assistance in the clean room facilities of MPIP. We also acknowledge G. Malliaras for relevant preliminary discussions and B. Meijer for support ; Funding Facilities of MPIP (clean room, device metrology, electronics, and mechanical workshop) are supported by the Max Planck Society (to P.W.M.B. and P.G.). nano@Stanford laboratories are supported by the National Science Foundation as part of the National Nanotechnology Coordinated Infrastructure under award ECCS-1542152 (to A.S.). This study is funded by a joint project between MPIP and the Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, grant no. MPIPICMS2019001 (to Y.v.d.B., I.K., and P.G.); European Union's Horizon 2020 Research and Innovation Programme, grant agreement no. 802615 (to Y.v.d.B.); the Carl-Zeiss Foundation (to P.G.); National Science Foundation and the Semiconductor Research Corporation, E2CDA award no. 1739795 (to A.S. and S.T.K.); and Stanford Graduate Fellowship fund (to S.T.K.)

Structure-property-activity relationships in solution processable polymer photocatalysts for hydrogen production from water were probed by varying the chemical structure of both the polymer side-chains and the polymer backbone. In both cases, the photocatalytic performance depends strongly on the inclusion of more polar groups, such as dibenzo[b,d]thiophene sulfone backbone units or oligo(ethylene glycol) side-chains. We used optical, spectroscopic, and structural characterisation techniques to understand the different catalytic activities of these systems. We find that although polar groups improve the wettability of the material with water in all cases, backbone and side-chain modifications affect photocatalytic performance in different ways: the inclusion of dibenzo[b,d]thiophene sulfone backbone units improves the thermodynamic driving force for hole transfer to the sacrificial donor, while the inclusion of oligo ethylene glycol side-chains aids the degree of polymer swelling and also extends the electron polaron lifetime. The best performing material, FS-TEG, exhibits a HER of 72.5 μmol h-1 for 25 mg photocatalyst (2.9 mmol g-1 h-1) when dispersed in the presence of a sacrificial donor and illuminated with λ > 420 nm light, corresponding to a hydrogen evolution EQE of 10% at 420 nm. When cast as a thin film, this HER was further boosted to 13.9 mmol g-1 h-1 (3.0 mmol m-2 h-1), which is among the highest rates in this field. ; AIC, RSS, MAZ, LW, and DW acknowledge the UK Engineering and Physical Sciences Research Council (EPSRC) for funding via grant EP/N004884/1. JN and DP acknowledge funding from the EPSRC via grants EP/P005543/1 and EP/R023581/1. AAYG thanks the EPSRC for award of a research fellowship (EP/P00928X/1). SJH thanks the EPSRC for a Centre for Doctoral Training post-graduate studentship (EP/L016702/1). JN also thanks the European Research Council for support under the European Union's Horizon 2020 research and innovation program (Grant Agreement No. 742708) and the Imperial College Research Computing Service for computational resources. JD and IM acknowledge financial support from the KAUST award OSR-2015-CRG4-2572. LQF acknowledges funding from the National Science Foundation (NSF DMR-1607242) and the NSF DMREF (award number 1629369).

A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [μC*] and current retentions up to 98% over 700 electrochemical switching cycles are developed. ; The authors acknowledge generous funding from KAUST for financial support. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology Office of Sponsored Research (OSR) under award nos. OSR-2018-CARF/CCF-3079, OSR-2015-CRG4-2572, and OSR-4106 CPF2019. The authors acknowledge EC FP7 Project SC2 (610115), EC H2020 (643791), and EPSRC Projects EP/G037515/1, EP/M005143/1, and EP/L016702/1. J.G., S.G., I.Z., M.B., and E.S. acknowledge funding from Knut and Alice Wallenberg Foundation, The Wallenberg Wood Science Center (KAW 2018.0452) and the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at NSC and HPC2N. A.G. and A.S. acknowledge funding from the TomKat Center for Sustainable Energy at Stanford University.

A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [mu C*] and current retentions up to 98% over 700 electrochemical switching cycles are developed. ; Funding Agencies|KAUSTKing Abdullah University of Science & Technology; King Abdullah University of Science and Technology Office of Sponsored Research (OSR) [OSR-2018-CARF/CCF-3079, OSR-2015-CRG4-2572, OSR-4106 CPF2019]; EC FP7 Project SC2 [610115]; EC H2020 [643791]; EPSRCEngineering & Physical Sciences Research Council (EPSRC) [EP/G037515/1, EP/M005143/1, EP/L016702/1]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Wallenberg Wood Science Center [KAW 2018.0452]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]; TomKat Center for Sustainable Energy at Stanford University

AbstractA critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in the interfacial charge-transfer (CT) state via the formation of hybrid energetic states. This requires small energetic offsets often detrimental for high external quantum efficiency (EQE). Here, we obtain OSC with both non-radiative voltage losses (0.24 V) and photocurrent losses (EQE > 80%) simultaneously minimised. The interfacial CT states separate into free carriers with ≈40-ps time constant. We combine device and spectroscopic data to model the thermodynamics of charge separation and extraction, revealing that the relatively high performance of the devices arises from an optimal adjustment of the CT state energy, which determines how the available overall driving force is efficiently used to maximize both exciton splitting and charge separation. The model proposed is universal for donor:acceptor (D:A) with low driving forces and predicts which D:A will benefit from a morphology optimization for highly efficient OSC. ; N.G. acknowledges the Imperial College Research Fellowship scheme. C.J.B. gratefully acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project no. 182849149-SFB 953. C.J.B. gratefully acknowledges financial support through the "Aufbruch Bayern" initiative of the state of Bavaria (EnCN and SFF) and the Bavarian Initiative "Solar Technologies go Hybrid" (SolTech) and funding from DFG project DFG INST 90/917. C.C.L. thanks the European Union for the financial support. G.C. acknowledges the support from the PRIN 2017 Project 201795SBA3—HARVEST.

Abstract The short exciton diffusion length associated with most classical organic semiconductors used in organic photovoltaics (5-20 nm) imposes severe limits on the maximum size of the donor and acceptor domains within the photoactive layer of the cell. Identifying materials that are able to transport excitons over longer distances can help advancing our understanding and lead to solar cells with higher efficiency. Here, we measure the exciton diffusion length in a wide range of nonfullerene acceptor molecules using two different experimental techniques based on photocurrent and ultrafast spectroscopy measurements. The acceptors exhibit balanced ambipolar charge transport and surprisingly long exciton diffusion lengths in the range of 20 to 47 nm. With the aid of quantum-chemical calculations, we are able to rationalize the exciton dynamics and draw basic chemical design rules, particularly on the importance of the end-group substituent on the crystal packing of nonfullerene acceptors. ; This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2018-CARF/CCF-3079. The work by V.M.L.C. is supported by a grant from STW/NWO (VIDI 13476). This is a publication by the FOM Focus Group "Next Generation Organic Photovoltaics", participating in the Dutch Institute for Fundamental Energy Research (DIFFER). D.A. acknowledges funding from the BMBF grants InterPhase and MESOMERIE (FKZ 13N13661, FKZ 13N13656) and the European Union Horizon 2020 research and innovation program "Widening materials models" under Grant Agreement No. 646259 (MOSTOPHOS). D.A. also acknowledges the KAUST PSE Division for hosting his sabbatical in the framework of the Division's Visiting Faculty program. A.M. acknowledges postdoctoral support of the Alexander von Humboldt Foundation. H.A.and M.M.N. acknowledge the support from the University of North Carolina General Administration Research Opportunity Initiative (ROI) and U.S. Department of Energy (DE-AC02-05CH11231) for X-ray data acquisition at beamline 7.3.3 at the Advanced Light Source (ALS) in Berkeley National Laboratory, California.

The development of non-fullerene acceptors (NFAs) has facilitated the realization of efficient organic solar cells (OSCs) with minimal burn-in losses and excellent long-term stability. However, the role of NFA molecular structures on device stability remains unclear, limiting commercialization of NFA-based OSCs. Herein, the photostability of 10 OSC devices, fabricated with various NFAs (O-IDTBR, EH-IDTBR, ITIC, and ITIC-M) blended with donor polymers (PTB7-Th, PffBT4T-2OD, and PBDB-T), is investigated. O-IDTBR and EH-IDTBR form highly stable devices with all three polymers, whereas ITIC and ITIC-M devices suffer from burn-in losses and long-term degradation. Conformational instability is found to be responsible for the poor photostability of ITIC and ITIC-M, resulting in poor device stability. Twisting and potential breakage of the chemical bond that links the end group to the main backbone of ITIC and ITIC-M molecules causes undesirable conformational changes. Potential strategies to overcome such detrimental photo-induced conformational changes in NFAs are proposed. ; Funding Agencies|European Social Fund via the Welsh Government; EPSRCUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) [EP/L015099/1, EP/T026219/1, EP/S020748/1]; UK EPSRCUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) [EP/L016702/1]; ATIP Programme grant [EP/T028513/1]; CSEM Brasil; Global Research Laboratory Program of the National Research Foundation (NRF) - Ministry of Science, ICT & Future Planning [NRF-2017K1A1A2013153]; UKRI Global Challenge Research Fund project, SUNRISE [EP/P032591/1]; Office of Sponsored Research (OSR) [OSR-2018-CRG/CCF-3079, OSR-2019-CRG8-4086, OSR-2018-CRG7-3749]; European Social Fund, European Union CSEM Brasil, Brazil European Research Council, European Union ERC Synergy Grant [SC2 (610115)]; European Unions Horizon 2020 research and innovation programme [952911]; project BOOSTER [862474]; project RoLA-FLEX; KAUSTKing ...