Imperial College London

Albrecht Group

Faculty of EngineeringDepartment of Chemical Engineering

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 7594 3704t.albrecht

 
 
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Location

 

R448ChemistrySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

119 results found

Carro P, Azofra LM, Albrecht T, Salvarezza RC, Pensa Eet al., 2021, Unraveling the Causes of the Instability of Au-n(SR)(x) Nanoclusters on Au(111), CHEMISTRY OF MATERIALS, Vol: 33, Pages: 3428-3435, ISSN: 0897-4756

Journal article

Pensa E, Azofra LM, Albrecht T, Salvarezza RC, Carro Pet al., 2020, Shedding Light on the Interfacial Structure of Low-Coverage Alkanethiol Lattices, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 124, Pages: 26748-26758, ISSN: 1932-7447

Journal article

Vladyka A, Albrecht T, 2020, Unsupervised classification of single-molecule data with autoencoders and transfer learning, MACHINE LEARNING-SCIENCE AND TECHNOLOGY, Vol: 1

Journal article

Elshahawy M, Pensa E, Albrecht T, Forster RJet al., 2020, Stepwise electrochemical deposition and single-molecule conductance of nucleic acid analogues, ELECTROCHIMICA ACTA, Vol: 346, ISSN: 0013-4686

Journal article

Wang X, Bennett TLR, Ismael A, Wilkinson LA, Hamill J, White AJP, Grace IM, Kolosov OV, Albrecht T, Robinson BJ, Long NJ, Cohen LF, Lambert CJet al., 2020, Scale-up of room-temperature constructive quantum interference from single molecules to self-assembled molecular-electronic films, Journal of the American Chemical Society, Vol: 142, Pages: 8555-8560, ISSN: 0002-7863

The realization of self-assembled molecular-electronic films, whose room-temperature transport properties are controlled by quantum interference (QI), is an essential step in the scale-up of QI effects from single molecules to parallel arrays of molecules. Recently, the effect of destructive QI (DQI) on the electrical conductance of self-assembled monolayers (SAMs) has been investigated. Here, through a combined experimental and theoretical investigation, we demonstrate chemical control of different forms of constructive QI (CQI) in cross-plane transport through SAMs and assess its influence on cross-plane thermoelectricity in SAMs. It is known that the electrical conductance of single molecules can be controlled in a deterministic manner, by chemically varying their connectivity to external electrodes. Here, by employing synthetic methodologies to vary the connectivity of terminal anchor groups around aromatic anthracene cores, and by forming SAMs of the resulting molecules, we clearly demonstrate that this signature of CQI can be translated into SAM-on-gold molecular films. We show that the conductance of vertical molecular junctions formed from anthracene-based molecules with two different connectivities differ by a factor of approximately 16, in agreement with theoretical predictions for their conductance ratio based on CQI effects within the core. We also demonstrate that for molecules with thioether anchor groups, the Seebeck coefficient of such films is connectivity dependent and with an appropriate choice of connectivity can be boosted by ∼50%. This demonstration of QI and its influence on thermoelectricity in SAMs represents a critical step toward functional ultra-thin-film devices for future thermoelectric and molecular-scale electronics applications.

Journal article

Awais N, Rodriguez P, Albrecht T, 2020, Surface Design: Exploiting the Instability of Small Nanoparticles on Metallic Substrates, ECS Meeting Abstracts, Vol: MA2020-01, Pages: 2865-2865

Journal article

Irving OJ, Albrecht T, 2020, DNA Assay-on-a-String: Rapid Detection of Marker Panels Against Sepsis, ECS Meeting Abstracts, Vol: MA2020-01, Pages: 1966-1966

Journal article

Yasini P, Shepard S, Albrecht T, Smeu M, Borguet Eet al., 2020, Combined Impact of Denticity and Orientation on Molecular-Scale Charge Transport, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 124, Pages: 9460-9469, ISSN: 1932-7447

Journal article

Awais N, Rodriguez P, Albrecht T, 2020, Surface Design: Exploiting the Instability of Small Nanoparticles on Metallic Substrates, ECS Transactions, Vol: 97, Pages: 885-892, ISSN: 1938-6737

Thiolated Au nanoparticles have been shown to undergo fast redistribution of the capping layer and subsequently of the metal core, when in contact with bare Au substrates. This is the result of an intricate interplay of entropic and enthalpic factors, which are likely affected by the choice of core metal and capping chemistry. This raises interesting questions, for example whether such a process could be used to modify and functionalize electrode substrates in a well-defined and controlled manner. Here, we report results for Pt and Au nanoparticles on Au and Pt substrates, based on the electrochemical response of the modified electrodes towards the oxidation of glycerol in alkaline media. Our study provides evidence that Pt nanoparticles on Au substrates remain relatively stable, while Au nanoparticles on Pt substrates readily decompose. This is in accordance with initial expectations based on the energetics of the thiol/metal bond.

Journal article

Carro P, Pensa E, Albrecht T, Salvarezza RCet al., 2020, Dynamics of RS-(Au-SR)(x) Staple Motifs on Metal Surfaces: From Nanoclusters to 2D Surfaces, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 124, Pages: 5452-5459, ISSN: 1932-7447

Journal article

Caballero AB, Cardo L, Claire S, Craig JS, Hodges NJ, Vladyka A, Albrecht T, Rochford LA, Pikramenou Z, Hannon MJet al., 2019, Assisted delivery of anti-tumour platinum drugs using DNA-coiling gold nanoparticles bearing lumophores and intercalators: towards a new generation of multimodal nanocarriers with enhanced action, CHEMICAL SCIENCE, Vol: 10, Pages: 9244-9256, ISSN: 2041-6520

Journal article

Kubánková M, Lin X, Albrecht T, Edel JB, Kuimova MKet al., 2019, Rapid fragmentation during seeded lysozyme aggregation revealed at the single molecule level, Analytical Chemistry, Vol: 91, Pages: 6880-6886, ISSN: 0003-2700

Protein aggregation is associated with neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. The poorly understood pathogenic mechanism of amyloid diseases makes early stage diagnostics or therapeutic intervention a challenge. Seeded polymerization that reduces the duration of the lag phase and accelerates fibril growth is a widespread model to study amyloid formation. Seeding effects are hypothesized to be important in the "infectivity" of amyloids and are linked to the development of systemic amyloidosis in vivo. The exact mechanism of seeding is unclear yet critical to illuminating the propagation of amyloids. Here we report on the lateral and axial fragmentation of seed fibrils in the presence of lysozyme monomers at short time scales, followed by the generation of oligomers and growth of fibrils.

Journal article

Pensa E, Karpowicz R, Jabaoński A, Trzybiński D, Woźniak K, Šakić D, Vrček V, Long NJ, Albrecht T, Kowalski Ket al., 2019, Gold-Induced Desulfurization in a Bis(ferrocenyl) Alkane Dithiol, Organometallics, ISSN: 0276-7333

© 2019 American Chemical Society. Thiol-modified ferrocenes on gold have been archetypical model systems for many fundamental charge transfer and other studies, since both thiol-gold and ferrocene redox chemistry are considered to be well-understood. Thus unexpectedly, we found that for a representative of a new class of flexibly linked bis-ferrocenyl compounds, namely, 1-10-bis(1-ferrocenyl)decane dithiol, surface immobilization on gold failed. Instead, in the presence of gold, molecular decomposition took place, resulting in sulfur-based adlayers and well-defined molecular elimination products, for which we provide spectroscopic evidence. Careful control experiments and comparison with related ferrocene compounds provide insight into the mechanism of the observed elimination reactions, as a combined effect of the molecular structure and the nature of the gold/sulfur bond. These findings, thus, have a broader impact on the design of molecular adlayers, for example, in the context of surface functionalization in sensing or the synthesis of gold nanoparticles.

Journal article

Leber R, Wilson L, Robaschik P, Inkpen M, Payne D, Long N, Albrecht T, Hirjibehedin C, Heutz Set al., 2019, Vacuum deposition of biferrocene thin films: growth strategies for stability and tuneable magnetism, 257th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Albrecht T, 2019, Single-Molecule Analysis with Solid-State Nanopores, Publisher: ANNUAL REVIEWS

Book

Loh AYY, Burgess CH, Tanase DA, Ferrari G, McLachlan MA, Cass AEG, Albrecht Tet al., 2018, Electric single-molecule hybridization detector for short DNA fragments, Analytical Chemistry, Vol: 90, Pages: 14063-14071, ISSN: 0003-2700

By combining DNA nanotechnology and high-bandwidth single-molecule detection in nanopipets, we demonstrate an electric, label-free hybridization sensor for short DNA sequences (<100 nucleotides). Such short fragments are known to occur as circulating cell-free DNA in various bodily fluids, such as blood plasma and saliva, and have been identified as disease markers for cancer and infectious diseases. To this end, we use as a model system an 88-mer target from the RV1910c gene in Mycobacterium tuberculosis, which is associated with antibiotic (isoniazid) resistance in TB. Upon binding to short probes attached to long carrier DNA, we show that resistive-pulse sensing in nanopipets is capable of identifying rather subtle structural differences, such as the hybridization state of the probes, in a statistically robust manner. With significant potential toward multiplexing and high-throughput analysis, our study points toward a new, single-molecule DNA-assay technology that is fast, easy to use, and compatible with point-of-care environments.

Journal article

Li B, Famili M, Pensa E, Grace I, Long NJ, Lambert C, Albrecht T, Cohen LFet al., 2018, Cross-plane conductance through a graphene/molecular monolayer/Au sandwich, Nanoscale, Vol: 10, Pages: 19791-19798, ISSN: 2040-3364

The functionalities offered by single-molecule electrical junctions are yet to be translated into monolayer or few-layer molecular films, where making effective and reproducible electrical contact is one of the challenging bottlenecks. Here we take a significant step in this direction by demonstrating that excellent electrical contact can be made with a monolayer biphenyl-4,4′-dithiol (BPDT) molecular film, sandwiched between gold and graphene electrodes. This sandwich device structure is advantageous, because the current flows through the molecules to the gold substrate in a ‘cross-plane’ manner, perpendicular to the plane of graphene, yielding high-conductance devices. We elucidate the nature of the cross-plane graphene/molecule/Au transport using quantum transport calculations and introduce a simple analytical model, which captures generic features of the current–voltage characteristic. Asymmetry in junction properties results from the disparity in electrode electrical properties, the alignment of the BPDT HOMO–LUMO energy levels and the specific characteristics of the graphene electrode. The experimental observation of scalability of junction properties within the junction area, in combination with a theoretical description of the transmission probability of the thiol–graphene contact, demonstrates that between 10% and 100% of the molecules make contact with the electrodes, which is several orders of magnitude greater than that achieved to date in the literature.

Journal article

Al-Zubeidi A, Godfrey D, Albrecht T, 2018, Disentangling chemical effects in ionic-liquid-based Cu leaching from chalcopyrite, JOURNAL OF ELECTROANALYTICAL CHEMISTRY, Vol: 819, Pages: 130-135, ISSN: 1572-6657

Journal article

Milan DC, Al-owaedi O, Bock S, Oerthel M, Inkpen M, Yufit D, Sobolev A, Long N, Albrecht T, Higgins S, Bryce M, Nichols R, Lambert C, Low Pet al., 2018, Insulated molecular wires: Inhibiting orthogonal contacts in metal complex, 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Pensa E, Albrecht T, 2018, Controlling the Dynamic Instability of Capped Metal Nanoparticles on Metallic Surfaces, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, Vol: 9, Pages: 57-62, ISSN: 1948-7185

Journal article

Albrecht T, Horswell S, Allerston LK, Rees NV, Rodriguez Pet al., 2018, Electrochemical processes at the nanoscale, CURRENT OPINION IN ELECTROCHEMISTRY, Vol: 7, Pages: 138-145, ISSN: 2451-9103

Journal article

shougee A, Konstantinou F, Albrecht T, Fobelets Ket al., 2018, Cyclic voltammetry peaks due to deep level traps in Si nanowire array electroes, IEEE Transactions on Nanotechnology, Vol: 17, Pages: 154-160, ISSN: 1536-125X

When metal-assisted chemical etching (MACE) is used to increase the effective surface area of Si electrodes for electrochemical capacitors, it is often found that the cyclic voltammetry characteristics contain anodic and cathodic peaks. We link these peaks to the charging-discharging dynamics of deep level traps within the nanowire system. The trap levels are associated with the use of Ag in the MACE process that can leave minute amounts of Ag residue within the nanowire system to interact with the H2O layer surrounding the nanowires in a room temperature ionic liquid. The influence of the traps can be removed by shifting the Fermi level away from the trap levels via spin-on doping. These results in lower capacitance values but improved charge-discharge cycling behavior. Low-frequency noise measurements proof the presence or absence of these deep level traps.

Journal article

Vilar R, Bandeira S, Gonzalez Garcia J, Pensa E, Albrecht Tet al., 2017, A redox-activated G-quadruplex DNA binder based on a platinum(IV)-salphen complex, Angewandte Chemie International Edition, Vol: 57, Pages: 310-313, ISSN: 1521-3757

There has been increasing interest in the development of small molecules that can selectively bind to G-quadruplex DNA structures. The latter have been associated to a number of key biological processes and therefore are proposed to be potential targets for drug development. In this paper we report the first example of a reduction-activated G-quadruplex DNA binder. We show that a new octahedral platinum(IV)-salphen complex does not interact with DNA in aqueous media at pH 7.4; however, upon addition of bio-reductants such as ascorbic acid or glutathione, the compound readily reduces to the corresponding square planar platinum(II) complex. In contrast to the parent platinum(IV) complex, the in situ generated platinum(II) complex binds to HTelo and c-Myc G-quadruplex DNA with affinity constants up to 106 M-1.

Journal article

Albrecht T, Slabaugh G, Alonso E, Al-Arif SMMRet al., 2017, Deep learning for single-molecule science, NANOTECHNOLOGY, Vol: 28, ISSN: 0957-4484

Journal article

Leber R, Wilson LE, Robaschik P, Inkpen MS, Payne DJ, Long NJ, Albrecht T, Hirjibehedin CF, Heutz Set al., 2017, High Vacuum Deposition of Biferrocene Thin Films on Room Temperature Substrates, Chemistry of Materials, Vol: 29, Pages: 8663-8669, ISSN: 0897-4756

Metallocenes are a promising candidate for future spintronic devices due to their versatile and tunable magnetic properties. However, single metallocenes, e.g., ferrocene, sublimate below room temperature, and therefore the implementation for future applications is challenging. Here, a method to prepare biferrocene thin films using organic molecular beam deposition (OMBD) is presented, and the effect of substrate and deposition rate on the film structure and morphology as well as its chemical and magnetic properties is investigated. On Kapton and Si substrates, biferrocene interacts only weakly with the substrate, and distinct grains scattered over the surface are observed. By incorporating a 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) seeding layer and depositing biferrocene at high deposition rates of 1.0 Å s–1, it is possible to achieve a well-ordered densely packed film. With spintronic applications in mind, the magnetic properties of the thin films are characterized using superconducting quantum interference device (SQUID) magnetometry. Whereas initial SQUID measurements show weak ferromagnetic behavior up to room temperature due to oxidized molecule fragments, measurements of biferrocene on PTCDA capped with LiF show the diamagnetic behavior expected of biferrocene. Through the successful deposition of biferrocene thin films and the ability to control the spin state, these results demonstrate a first step toward metallocene-based spintronics.

Journal article

Cadinu P, Paulose Nadappuram B, Lee DJ, Sze JYY, Campolo G, Zhang Y, Shevchuk A, Albrecht T, Korchev Y, Ivanov AP, Edel JBet al., 2017, Single molecule trapping and sensing using dual nanopores separated by a zeptoliter nanobridge, Nano Letters, Vol: 17, Pages: 6376-6384, ISSN: 1530-6984

There is a growing realization, especially within the diagnostic and therapeutic community, that the amount of information enclosed in a single molecule can not only enable a better understanding of biophysical pathways, but also offer exceptional value for early stage biomarker detection of disease onset. To this end, numerous single molecule strategies have been proposed, and in terms of label-free routes, nanopore sensing has emerged as one of the most promising methods. However, being able to finely control molecular transport in terms of transport rate, resolution, and signal-to-noise ratio (SNR) is essential to take full advantage of the technology benefits. Here we propose a novel solution to these challenges based on a method that allows biomolecules to be individually confined into a zeptoliter nanoscale droplet bridging two adjacent nanopores (nanobridge) with a 20 nm separation. Molecules that undergo confinement in the nanobridge are slowed down by up to 3 orders of magnitude compared to conventional nanopores. This leads to a dramatic improvement in the SNR, resolution, sensitivity, and limit of detection. The strategy implemented is universal and as highlighted in this manuscript can be used for the detection of dsDNA, RNA, ssDNA, and proteins.

Journal article

Albrecht T, 2017, Progress in single-biomolecule analysis with solid-state nanopores, CURRENT OPINION IN ELECTROCHEMISTRY, Vol: 4, Pages: 159-165, ISSN: 2451-9103

Journal article

Al-Owaedi OA, Bock S, Milan DC, Oerthel M-C, Inkpen MS, Yufit DS, Sobolev AN, Long NJ, Albrecht T, Higgins SJ, Bryce MR, Nichols RJ, Lambert CJ, Low PJet al., 2017, Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions, Nanoscale, Vol: 9, Pages: 9902-9912, ISSN: 2040-3364

Metal complexes are receiving increased attention as molecular wires in fundamental studies of the transport properties of metal|molecule|metal junctions. In this context we report the single-molecule conductance of a systematic series of d8 square-planar platinum(II) trans-bis(alkynyl) complexes with terminal trimethylsilylethynyl (C[triple bond, length as m-dash]CSiMe3) contacting groups, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H4C[triple bond, length as m-dash]CSiMe3}2(PR3)2 (R = Ph or Et), using a combination of scanning tunneling microscopy (STM) experiments in solution and theoretical calculations using density functional theory and non-equilibrium Green's function formalism. The measured conductance values of the complexes (ca. 3–5 × 10−5G0) are commensurate with similarly structured all-organic oligo(phenylene ethynylene) and oligo(yne) compounds. Based on conductance and break-off distance data, we demonstrate that a PPh3 supporting ligand in the platinum complexes can provide an alternative contact point for the STM tip in the molecular junctions, orthogonal to the terminal C[triple bond, length as m-dash]CSiMe3 group. The attachment of hexyloxy side chains to the diethynylbenzene ligands, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H2(Ohex)2C[triple bond, length as m-dash]CSiMe3}2(PPh3)2 (Ohex = OC6H13), hinders contact of the STM tip to the PPh3 groups and effectively insulates the molecule, allowing the conductance through the full length of the backbone to be reliably measured. The use of trialkylphosphine (PEt3), rather than triarylphosphine (PPh3), ancillary ligands at platinum also eliminates these orthogonal contacts. These results have significant implications for the future design of organometallic complexes for studies in molecular junctions.

Journal article

Kuzmina O, Symianakis E, Godfrey D, Albrecht T, Welton Tet al., 2017, Ionic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 19, Pages: 21556-21564, ISSN: 1463-9076

We studied leaching of Cu and Fe from naturally occurring chalcopyrite ore using aqueous solutions of ionic liquids (ILs) based on imidazolium and ethylammonium cations and hydrogensulfate, nitrate, acetate or dicyanamide anions. Liquid, solid and gas phases of the leaching systems were characterised. We have shown that nonoxidative leaching is greatly dependant not only on temperature and pH, but on the anion species of the IL. Solutions of 1-butylimidazolium hydrogen sulfate exhibited the best leaching performance among hydrogen sulphate ILs. We have suggested that the formation of an oxide layer in some ILs may be responsible for a reduced leaching ability. The analysis of the gas phase showed the production of CO2 and CS2 in all leached samples. Our results suggested that the CS2 produced upon leaching could be responsible for decreasing the sulfur, but not oxide, layer on the surface of chalcopyrite samples and therefore more efficient leaching. This is the first study, to our knowledge, to provide a systematic comparison of the leaching performance of ILs composed of different anions and cations and without added oxidants.

Journal article

Long NJ, albrecht T, wilson L, white A, winter R, hassenruck Cet al., 2017, Ferrocene- and biferrocene-containing macrocycles towards single molecule electronics, Angewandte Chemie-International Edition, Vol: 56, Pages: 6838-6824, ISSN: 1521-3773

Cyclic multiredox centered systems are currently of great interest, with new compounds being reported and developments made in understanding their behavior. Efficient, elegant, and high-yielding (for macrocyclic species) synthetic routes to two novel alkynyl-conjugated multiple ferrocene- and biferrocene-containing cyclic compounds are presented. The electronic interactions between the individual ferrocene units have been investigated through electrochemistry, spectroelectrochemistry, density functional theory (DFT), and crystallography to understand the effect of cyclization on the electronic properties and structure.

Journal article

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