Table of contents

Quantum materials are central for the development of novel functional systems that are often based on interface specific phenomena. Fabricating controlled interfaces between quantum materials requires adopting a flexible growth technique capable to synthesize different materials within a single-run deposition process with high control of structure, stoichiometry, and termination. Among the various available thin film growth technologies, pulsed laser deposition (PLD) allows controlling the growth of diverse materials at the level of single atomic layers. In PLD the atomic species are supplied through an ablation process of a stoichiometric target either in form of polycrystalline powders or of a single crystal. No carrier gases are needed in the deposition process. The ablation process is compatible with a wide range of background pressure. We present results of thin-film growth by PLD obtained by using an Nd:YAG infrared pulsed laser source operating at its first harmonics. With respect to the traditional PLD systems—based on excimer KrF UV-lasers—optimal conditions for the growth of thin films and heterostructures are reached at large target-to-substrate distance. Merits and limitations of this approach for growing oxide and non-oxide thin films are discussed. The merits of an Nd:YAG laser to grow very high-quality thin films suggest the possibility of implementing compact in-situ setups e.g. integrated with analytical instrumentation under ultra-high vacuum conditions.

Metal additive manufacturing (AM) presents advantages such as increased complexity for a lower part cost and part consolidation compared to traditional manufacturing. The multiscale, multiphase AM processes have been shown to produce parts with non-homogeneous microstructures, leading to variability in the mechanical properties based on complex process–structure–property (p-s-p) relationships. However, the wide range of processing parameters in additive machines presents a challenge in solely experimentally understanding these relationships and calls for the use of digital twins that allow to survey a larger set of parameters using physics-driven methods. Even though physics-driven methods advance the understanding of the p-s-p relationships, they still face challenges of high computing cost and the need for calibration of input parameters. Therefore, data-driven methods have emerged as a new paradigm in the exploration of the p-s-p relationships in metal AM. Data-driven methods are capable of predicting complex phenomena without the need for traditional calibration but also present drawbacks of lack of interpretability and complicated validation. This review article presents a collection of physics- and data-driven methods and examples of their application for understanding the linkages in the p-s-p relationships (in any of the links) in widely used metal AM techniques. The review also contains a discussion of the advantages and disadvantages of the use of each type of model, as well as a vision for the future role of both physics-driven and data-driven models in metal AM.

The era of two-dimensional (2D) materials, in its current form, truly began at the time that graphene was first isolated just over 15 years ago. Shortly thereafter, the use of 2D hexagonal boron nitride had expanded in popularity, with use of the thin isolator permeating a significant number of fields in condensed matter and beyond. Due to the impractical nature of cataloguing every use or research pursuit, this review will cover ground in the following three subtopics relevant to this versatile material: growth, electrical measurements, and applications in optics and photonics. Through understanding how the material has been utilized, one may anticipate some of the exciting directions made possible by the research conducted up through the turn of this decade.

Sodium-ion batteries offer a low-cost sustainable alternative to current lithium-ion batteries and can be made on the same manufacturing lines. The sustainability arises from the low cost, reduction in the use of critical elements and strategic materials, and potential long-life. To maximize their potential, higher energy density batteries are required, this can be achieved in part through the stabilization of higher voltage cathode materials. In this review we summarize the failure and degradation processes associated with the high capacity and higher voltage layered oxide cathode materials. Material crystal structure rearrangements, electrolyte oxidation, particle cracking and reactive surfaces form most of the degradation mechanisms. Strategies to overcome these processes are discussed in detail, and the synergistic requirements to stabilize the materials structure and the interfaces highlighted. The importance of surface engineering in future materials design is emphasized.

Additive manufacturing (AM) as a highly digitalized manufacturing technology is capable of the implementation of the concept of the digital twin (DT), which promises highly automated and optimized part production. Since the DT is a quite novel concept requiring a wide framework of various technologies, it is not state of the art yet, though. Especially the combination with artificial intelligence (AI) methods is still challenging. Applying the methodology of the systematic review, the state of the art regarding the DT in AM with emphasis of required technologies and current challenges is assessed. Furthermore, the topic of AI is investigated focusing the main applications in AM as well as the possibility to integrate today's approaches into a DT environment.

Photodynamic therapy (PDT) has been clinically applied to cure various diseases including cancer. Indeed, photophrin (porfimer sodium, Axcan Pharma, Montreal, Canada), a heterogenous mixture of porphyrins, was the first photosensitizer (PS) approved for the treatment of human bladder cancer in 1993 in Canada. Over the past 10 years the use of PDT in the treatment of benign and malignant lesions has increased dramatically. However, PDT is still considered as an adjuvant strategy due to its limitations, primarily including low tissue penetration by light and inaccurate lesion selectivity by the PSs. To overcome this scenario, new technologies and approaches including nanotechnology have been incorporated into the concept of PS formulations as PS delivery systems, as PSs per se or as energy transducers. The ideal nanophotosensitizer (NPS) for cancer therapy should possess the following characteristics: biocompatibility and biodegradability without toxicity, stability in physiological conditions, tumor specific targeting, strong near infrared absorption for efficient and sufficient light absorbance and large singlet oxygen quantum yield for PDT. To fulfill these requirements, several nanoscale delivery platforms and materials have been developed. In this review we will focus on the state of the art of nanotechnology contributions to the optimization of PDT as a therapeutic alternative to fight against cancer. For this purpose we will start from the basic concepts of PDT, discuss the versatility in terms of NPS formulations and how to tackle the deficiencies of the current therapy. We also give our critical view and suggest recommendations for improving future research on this area.

Carbon-based materials have become indispensable in the field of electrochemical applications, especially for energy storage or conversion purposes. A large diversity of materials has been proposed and investigated in the last years. In this mini-review, we present recent advances in the design of carbon-based materials for application in vanadium redox flow batteries. As main part, different modification and fabrication methods for carbon-based electrodes are described. The decoration of carbon felts and graphite felts with metals or metal compounds to enhance mostly the electrocatalysis of the negative side is illustrated with examples. Furthermore, various options of synthesizing porous C–C composites are discussed, with specific emphasis on graphene-based composites as well as nitrogen doped composites and biomass-derived carbons. Apart from that the method of electrospinning is also examined in detail, a method which not only allows the production of nanofibrous high surface area electrodes, but also allows adaptation of fiber thickness and architecture. In this review the significant strengths of each method are pointed out, but also particular weaknesses are discussed with respect to the later battery performance. Finally, an outlook is given pointing to the remaining challenges that need to be overcome in the future.

Since 2009, metal halide perovskites have attracted a great deal of attention in different optoelectronic applications, such as solar cells, photodetectors (PDs), light-emitting diodes, lasers etc, owing to their excellent electrical and optoelectrical properties. However, since the discovery of graphene, atomically thin 2D materials have been the central focus of materials research due to its exciting properties. Thus, integrating 2D materials with perovskite material can be highly promising for various optoelectronic applications, in particular for ultrasensitive photodetection. In these PDs, 2D materials serve various roles, such as charge transport layer, Schottky contacts, photo absorbers, etc, while perovskite is the light-harvesting active layer. In this review, we focus on the recent findings and progress on metal halide perovskite/2D material phototransistors and hybrid PDs. We comprehensively summarize recent efforts and developments of perovskite/graphene, perovskite/transition-metal dichalcogenides, perovskite/black phosphorus, and perovskite/MXene based phototransistor and heterojunction PDs from the perspective of materials science and device physics. The perovskite/2D material phototransistor can exhibit very high photoresponsivity and gain due to the amplification function of transistors and the pronounced photogating effect in 2D material, while perovskite/2D material heterojunction PD can operate without external bias due to built-in potential across the heterojunction. This review also provides state-of-the-art progress on flexible, transparent, self-powered and PD systems and arrays based on perovskite/2D materials. After summarizing the ongoing research and challenges, the future outlook is presented for developing metal halide perovskite/2D material hybrid PDs for practical applications.

Developing electrocatalysts that can completely oxidize ethanol oxidation is critical for commercializing direct ethanol fuel cells. Here, we tailored synthesis of mesoporous PdBi films by employing an electrochemical-assisted micelle assembly approach. The as-prepared film exhibited superior electrocatalytic activity and stability toward ethanol oxidation reaction, which is promising forpractical applications.

Responsible disposal and recycling are essential for the sustainability of the battery market, which has been exponentially growing in the past few years. Under such a scenario, the recycling of materials of less economic value, but environmentally much more sustainable like LiFePO₄, represents an economic challenge. In this paper an approach to recover used FePO₄ electrodes from calendar aged Lithium-ion (Li-ion) batteries and their reuse in Sodium-ion (Na-ion) cells is proposed. The electrochemical performances of the Na-ion cell are shown to be comparable with previously reported values and, since the electrode can retain the original microstructure and distribution, electrode processing can be avoided. A proof of concept of a NaFePO₄//hard carbon full cell using a very high positive electrode loading optimized for Li-ion batteries (≈14 mg cm⁻²) is shown.

Sodium ion batteries are widely considered to be a feasible, cost-effective, and sustainable energy storage alternative to Lithium, especially for large-scale energy storage applications. Next generation, safer electrolytes based on ionic liquid (IL) and organic ionic plastic crystals (OIPCs) have been demonstrated as electrochemically stable systems which show superior performance in both Li and Na applications. In particular, phosphonium‐based systems outperform most studied nitrogen‐based ILs and OIPCs. In this study triisobutyl(methyl)phosphonium bis(fluorosulfonyl)imide ([P_1i444][FSI]) OIPC mixed with 20 mol% of NaFSI or NaTFSI were combined with an electrospun polyvinylidene fluoride (PVDF) support to create self-standing electrolyte membranes, and their thermal phase behaviour and ionic conductivity were investigated and compared with the bulk electrolytes. The ability of the solid-state composite electrolytes to support the cycling of sodium metal with good efficiency and without breakdown were examined in sodium metal symmetrical coin cells. The sodium transference number was determined to be 0.21. The electrochemical performance of Na/Na₃V₂(PO₄)₃ cells incorporating the composite electrolytes, including good cycling stability and rate capability, is also reported. Interestingly, the mixed anion systems appear to outperform the composite electrolyte containing only FSI anions, which may relate to electrolyte interactions with the PVDF fibres.

We report an experimental study of the structure of polymer-capped gold nanorods (AuNRs) binding to model phospholipid monolayers to elucidate the mechanism that drives the insertion of the AuNRs into phospholipid membranes. The experimental system consists of four different cases of AuNRs interacting with lipid monolayers: cationic and anionic polymer-capped AuNRs suspended in the pure water subphase of Langmuir monolayers of zwitterionic and anionic phospholipids, separately. Liquid surface x-ray reflectivity was used to measure in situ the structure of the lipids and AuNRs at the air-water interface with sub-nanometer resolution, yielding quantitatively the amount, orientation, as well as depth of AuNR insertion into the monolayer. In the case of a zwitterionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine, cationic Poly-diallyldimethylammonium chloride (PDC) capped AuNRs (PDC-AuNRs) adsorbed peripherally at the water-lipid interface whereas the anionic Poly-sodium 4-styrenesulfonate (PSS) capped AuNRs (PSS-AuNRs) penetrated deeply into the lipid monolayer. In the case of an anionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (SOPG), PDC-AuNRs inserted into the monolayer whereas PSS-AuNRs were not even attracted to the monolayer. The results suggest that the adsorption process of AuNRs to model membranes may proceed through different mechanisms. In the presence of a charged membrane, electrostatic interactions drove the AuNRs to or away from the membrane depending on the nature of the charge of the lipid film and the AuNRs, while in the presence of a zwitterionic membrane, both electrostatic interactions and hydrophobic interactions mediated the insertion of the AuNRs into the membrane.

Surface traps significantly influence the charge carrier dynamics within semiconductor nanocrystals, introducing non-radiative exciton recombination channels which are detrimental for their applications. Understanding the nature of these trap states and modulating them synthetically bears immense potential in designing defect-free colloidal semiconductor nanocrystals for efficient optoelectronic devices. Thus, systems devoid of surface traps can be used to study the relaxation pathways of excitons generated within these nanocrystals. In this work, we study the ultrafast charge carrier relaxation dynamics upon near-edge resonance excitation and above-resonance excitation in CdS nanocrystals using ultrafast transient absorption spectroscopy, in order to understand intraband cooling and mid-gap trap states. The time-resolved studies reveal that the above bandgap excitation results in a three-step process, including instantaneous growth followed by a fast sub-picosecond decay and a long-lived (>1 ns) excited state or a trap state recombination. The large percentage of long-lived excitons in CdS nanocrystals elucidates the defect-free nature of the system arising from the absence of surface states.

Designing electrocatalysts from the perspective of modulating electronic structure and morphology has received considerable research interest in enhancing the electrocatalytic performance for oxygen evolution reaction (OER). In this work, nickel–iron based sulfides were synthesized through a one-pot hydrothermal approach which is characterized as defect-rich Ni₉S₈/Fe₅Ni₄S₈ heterostructured nanoparticles. The presence of two phases, numerous defects, and uniformly distributed nanoparticles with the porous structure are conducive to modulating electronic structure, facilitating electron and mass transport, allowing the effective accessibility of active sites. The as-prepared Ni₉S₈/Fe₅Ni₄S₈ exhibits enhanced electrocatalytic OER activity and long-lasting stability, which needs an overpotential of 239 mV for yielding 10 mA cm⁻² and long-term stability better than RuO₂. Furthermore, when employed in a two-electrode overall water splitting system, the catalyst coupled with Pt/C configuration exhibits comparable electrocatalytic performance to Pt/C and RuO₂ based electrolyzer. This work not only offers a highly efficient and promising candidate catalyst for electrocatalytic water oxidation but also provides a simple synthesis method to heterostructured nanoparticles for other energy-related applications.

This paper provides a pedagogical introduction to recent developments in geometrical and topological band theory following the discovery of graphene and topological insulators. Amusingly, many of these developments have a connection to contributions in high-energy physics by Dirac. The review starts by a presentation of the Dirac magnetic monopole, goes on with the Berry phase in a two-level system and the geometrical/topological band theory for Bloch electrons in crystals. Next, specific examples of tight-binding models giving rise to lattice versions of the Dirac equation in various space dimension are presented: in 1D (Su–Schrieffer–Heeger (SSH) and Rice–Mele models), 2D (graphene, boron nitride, Haldane model) and 3D (Weyl semi-metals). The focus is on topological insulators and topological semi-metals. The latter have a Fermi surface that is characterized as a topological defect. For topological insulators, the two alternative view points of twisted fiber bundles and of topological textures are developed. The minimal mathematical background in topology (essentially on homotopy groups and fiber bundles) is provided when needed. Topics rarely reviewed include: periodic versus canonical Bloch Hamiltonian (basis I/II issue), Zak versus Berry phase, the vanishing electric polarization of the SSH model and Dirac insulators.

Using an 8-band $\textbf{k}\cdot\textbf{p}$ model it is demonstrated through the combination of strain and piezoelectricity that increasing the InN quantum-well thickness of a GaN-InN-GaN device changes the InN material from a positive bandgap semiconductor to a topological insulator (negative bandgap). Moderate strain tuning of a four monolayer InN layer for a GaN-InN-GaN device reveals a giant (one order of magnitude) tuning of current–voltage characteristics. It is verified that piezoelectricity plays an important role in controlling electron transport through the InN layer.

Semi-transparent solar cells are the next step for photovoltaics into our daily life. Over the last years, kesterite-type material has attracted a special attention to be used as an absorber in thin-film solar cells because of its low toxicity and earth abundant constituents. Here, Cu₂ZnGeSe₄ (CZGSe) thin films are grown by co-evaporation and subsequent annealing at a maximum temperature of 480 °C or 525 °C onto Mo/V₂O₅/FTO/glass stacks. The goal of this work is to investigate the influence of the annealing temperature on the composition, morphology, vibrational properties, and transmittance of CZGSe layers, the formation of secondary phases, and distribution of elements within the absorber layer as well as on the optoelectronic properties of the corresponding solar cell devices. Raising the annealing temperature to 525 °C leads to a more uniform distribution of Cu, Zn, Ge and Se throughout the absorber layer, a reduction of the presence of the GeSe₂ secondary phase, which is mainly detected at 480 °C, a larger grain size and the formation of a thicker MoSe₂ layer at the CZGSe/back contact interface. The strategy of increasing the annealing temperature allows for improved J–V characteristics and higher spectral response resulting in an enhanced device performance of 5.3% compared to 4.2% when using 525 °C and 480 °C, respectively. Both absorber layers present an optical band gap energy of 1.47 eV. Furthermore, higher annealing temperature has beneficial effect to the CZGSe-based devices without losses in total transmitted light because of the higher diffuse transmittance. This work shows first promising semi-transparent CZGSe-based solar cells possibly open up new routes of applications.

Triboelectric devices capable of harvesting ambient mechanical energy have attracted attention in recent years for powering biomedical devices. Typically, triboelectric energy harvesters rely on contact-generated charges between pairs of materials situated at opposite ends of the triboelectric series. However, very few biocompatible polymeric materials exist at the 'tribopositive' end of the triboelectric series. In order to further explore the use of triboelectric energy harvesting devices within the body, it is necessary to develop more biocompatible tribopositive materials and look into ways to improve their triboelectric performance in order to enhance the harvested power output of these devices. Poly-L-lactic acid (PLLA) is a tribopositive biocompatible polymer, frequently used in biomedical applications. Here, we present a way to improve the triboelectric output of nanostructured PLLA through fine control of its crystallinity via a customised template-assisted nanotube (NT) fabrication process. We find that PLLA NTs with higher values of crystallinity (∼41%) give rise to a threefold enhancement of the maximum triboelectric power output as compared to NTs of the same material and geometry but with lower crystallinity (∼13%). Our results thus pave the way for the production of a viable polymeric and biocompatible tribopositive material with improved power generation, for possible use in implantable triboelectric nanogenerators.

The orthorhombic γ-black phase of CsPbI₃ is well-known to be unstable at room temperature and strategies are needed to counteract its transformation tendency. In this paper we compare γ-black CsPbI₃ thin films (∼80 nm) formed via two different routes: a fast quenching of the cubic α-phase from 325 °C (HT-γ) or spontaneously cooling the layer from 80 °C (LT-γ). The successful application of the second procedure is allowed by the use of a mother solution containing Europium with an Eu/Pb ratio as small as 5%. This has been indeed used to form both LT-γ and HT-γ thin films. The phase transition during the heating and cooling pathways is followed in situ by spectroscopic ellipsometry and x-ray diffraction analyses. We demonstrate that both γ-black phases exhibit the same absorption features and critical points as depicted in very details by the dielectric functions. Minor differences can be found in the intensity of the absorption coefficient, assigned to an improved lattice quality in the layer that has experienced the high temperature path. On the other hand, α-black and δ-yellow phases show different critical points in the optical transitions. Besides providing benchmarking optical parameters to discriminates the different phases, we demonstrate that the LT-γ phase closely competes with the HT-γ counterpart during stress tests for stability, with the first one more suited for tandem monolithic architectures that require thermal treatments under 200 °C.

We present our recent development of an integrated mesoscale digital twin (DT) framework for relating processing conditions, microstructures, and mechanical responses of additively manufactured (AM) metals. In particular, focusing on the laser powder bed fusion technique, we describe how individual modeling and simulation capabilities are coupled to investigate and control AM microstructural features at multiple length and time scales. We review our prior case studies that demonstrate the integrated modeling schemes, in which high-fidelity melt pool dynamics simulations provide accurate local thermal profiles and histories to subsequent AM microstructure simulations. We also report our new mechanical response modeling results for predicted AM microstructures. In addition, we illustrate how our DT framework has been validated through modeling–experiment integration, as well as how it has been practically utilized to guide and analyze AM experiments. Finally, we share our perspectives on future directions of further development of the DT framework for more efficient, accurate predictions and wider ranges of applications.

To produce multi-dopant ferrite nanoparticles, the 'Extended LaMer' and seed-mediated growth techniques were combined by first utilizing traditional thermal decomposition of metal acetylacetonates to produce seed particles, followed by a continuous injection of metal oleate precursors to increase the volume of the seed particles. With the choice of precursors for the seeding and dripping stage, we successfully synthesized particles with manganese precursor for seeding and cobalt precursor for dripping (Mn_0.18Co_1.04Fe_1.78O₄, 17.6 ± 3.3 nm), and particles with cobalt precursors for seeding and manganese precursors for dripping (Mn_0.31Co_0.74Fe_1.95O₄, 19.0 ± 1.9 nm). Combining transmission electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction, and vibrating sample magnetometry, we conclude that the seed-mediated drip method is a viable method to produce multi-dopant ferrite nanoparticles, and the size of the particles was mostly determined by the seeding stage, while the magnetic properties were more affected by the dripping stage.

The evolution of low-dimensional materials has frequently revolutionized new intriguing physical standards and suggests a unique approach to scientifically design a novel device. However, scaling down of spin-electronic devices entails in-depth knowledge and precise control on engineering interfacial structures, which unveils the exciting opportunity. To reveal exotic quantum phases, atomically thin two-dimensional van der Waals material, embraces control and tuning of various physical states by coupling with peripheral perturbation such as pressure, photon, gating, Moire pattern and proximity effect. Herein, we discuss the physical property of a pristine material which can be converted via proximity effects to attain intrinsic spin-dependent properties from its adjacent material like magnetic, topological or spin–orbit phenomena. Realizing magnetic proximity effect in atomically thin vdW heterostructure not only balance the traditional techniques of designing quality spin interface by doping, defects or surface modification, but also can overcome their restrictions for modelling and fabricate novel spin-related devices in nanoscale phases. The proximitized van der Waals heterostructure systems unveil properties, which cannot be realized in any integral component of considered heterostructure system. These proximitized van der Waals material provide an ideal platform for exploring new physical phenomena, which delivers a broader framework for employing novel materials and investigate nanoscale phases in spintronics and valleytronics.

According to data released by the World Health Organization, more than one billion people in the world experience some form of disability, in which they face all kinds of inconveniences. As a practical tool to help people with disabilities participate in social life, assistive devices for the people with disabilities play an important role in their daily lives. As an effective electromechanical signal conversion technology, triboelectric nanogenerator (TENG) has been successfully applied to various types of biosensors. This review aims to provide an overview of the development of assistive devices for the people with disabilities based on TENG with five categories: hearing, vision, pronunciation, gustation and limb/joint, according to the classification method of the impaired part. Meanwhile, a human–computer interaction system for the people with disabilities is also investigated. Finally, the prospect and potential challenges of this new field are discussed.

A patterned structure of monolithic hexagonal boron nitride (hBN) on a glass substrate, which can enhance the emission of the embedded single photon emitters (SPEs), is useful for onchip single-photon sources of high-quality. Here, we design and demonstrate a monolithic hBN metasurface with quasi-bound states in the continuum mode at emission wavelength with ultrahigh Q values to enhance fluorescence emission of SPEs in hBN. Because of ultrahigh electric field enhancement inside the proposed hBN metasurface, an ultrahigh Purcell factor (3.3 × 10⁴) is achieved. In addition, the Purcell factor can also be strongly enhanced in most part of the hBN structure, which makes the hBN metasurface suitable for e.g. monolithic quantum photonics.

For biologically relevant macromolecules such as intrinsically disordered proteins, internal degrees of freedom that allow for shape changes have a large influence on both the motion and function of the compound. A detailed understanding of the effect of flexibility is needed in order to explain their behavior. Here, we study a model system of freely-jointed chains of three to six colloidal spheres, using both simulations and experiments. We find that in spite of their short lengths, their conformational statistics are well described by two-dimensional Flory theory, while their average translational and rotational diffusivity follow the Kirkwood–Riseman scaling. Their maximum flexibility does not depend on the length of the chain, but is determined by the near-wall in-plane translational diffusion coefficient of an individual sphere. Furthermore, we uncover shape-dependent effects in the short-time diffusivity of colloidal tetramer chains, as well as non-zero couplings between the different diffusive modes. Our findings may have implications for understanding both the diffusive behavior and the most likely conformations of macromolecular systems in biology and industry, such as proteins, polymers, single-stranded DNA and other chain-like molecules.

We report exceptionally large tunnel magnetoresistance (TMR) for biomolecular tunnel junctions based on ferritins immobilized between Ni and EGaIn electrodes. Ferritin stores iron in the form of ferrihydrite nanoparticles (NPs) and fulfills the following roles: (a) it dictates the tunnel barrier, (b) it magnetically decouples the NPs from the ferromagnetic (FM) electrode, (c) it stabilizes the NPs, and (d) it acts as a spin filter reducing the complexity of the tunnel junctions since only one FM electrode is required. The mechanism of charge transport is long-range tunneling which results in TMR of 60 ± 10% at 200 K and 25 ± 5% at room temperature. We propose a magnon-assisted transmission to explain the substantially larger TMR switching fields (up to 1 Tesla) than the characteristic coercive fields (a few Gauss) of ferritin ferrihydrite particles at T < 20 K. These results highlight the genuine potential of biomolecular tunnel junctions in designing functional nanoscale spintronic devices.