Maksym Kovalenko

Perovskite semiconductors CsPbX3 can simply be melt-cast in a conventional chemical laboratory, yielding inexpensive and excellent X-ray detector arrays.

www.sciencedirect.com/science/arti...

Electrochemical Control over Electron Density of InAs Quantum Dots Control over the electron density and conductivity is a cornerstone of semiconductor technology. Here, we report electrochemical control over electron density and conductivity in films of InAs colloidal quantum dots (QDs) capped with ethanedithiol ligands. The quantum-confined twofold degenerate 1S1/2(e) electron state can be reversibly and completely filled. Increasing the electron population yields four bleach features in the optical-absorption spectrum associated transitions to the 1S1/2(e) state, and state-resolved electronic conductivity which follows the 1S1/2(e) density of states, reaching a maximum of 0.45 S/m at 0.5 electrons per QD. The absence of 1P(e) bleach features and state-resolved conductivity imply a wide separation between the 1S1/2(e) and 1P(e) states resulting in electronic transport between 1S(e) states exclusively. The reversible electrochemistry of InAs QDs films allows determination of the absolute energy levels. InAs QDs of 4.2 nm in edge length and capped with ethanedithiol ligands are natively n-doped with the Fermi level at −4.6 eV, the 1S1/2(e) state at −4.28 eV and the 1S3/2(h) state at −5.54 eV vs vacuum. This work establishes a way to precisely control the charge carrier density and conductivity and gives insights into the charge transport properties and electronic structure of InAs QD films, opening the possibility of making devices with InAs QDs in which the charge carrier density is precisely controlled electrochemically.

pubs.acs.org/doi/full/10....

Noninvasive Quality Assessment of Melt-Grown Cesium Lead Bromide Perovskite by Nuclear Quadrupole Resonance Spectroscopy Melt-grown, highly crystalline CsPbBr3 has been intensely investigated as a semiconductor for direct hard radiation detection. While the phase purity and crystallinity of the CsPbBr3 ingots are assess...

NQR of halide nuclei is extremely helpful, simple and affordable as a solid-state characterization method. Think of it as magnet-free NMR... Our group shows, for example, that you can sense small difference in the crystallinity of bulk cesium lead halide perovskites.
pubs.acs.org/doi/10.1021/...

Navigating the Catholyte Landscape in All-Solid-State Batteries All-solid-state batteries are widely regarded as the next frontier in electrochemical energy storage, offering the potential to surpass the energy density and safety limits of conventional lithium-ion batteries. Among the factors governing their performance, paramount are the choice and functionality of the solid-state electrolyte (SSE) as a catholyte within the composite positive electrode. This perspective critically examines the applicability and potential of the three most intensively studied inorganic SSE families, namely oxides, sulfides, and chlorides, as catholytes. We discuss their respective advantages, limitations, and compatibility with common cathode active materials, as well as the remaining knowledge gaps. We then assess whether any of the current SSE classes can be employed as a stand-alone SSE for all-solid-state batteries, or whether composite architectures combining multiple SSEs will ultimately be required.

Solid-state electrolytes (SSE) are the cornerstone of the solid state battery. They must be included also into the positive electrode architecture.
What are our current choices, pros and cons of each? We discuss that in our latest perspective in ACS Energy Letters.

pubs.acs.org/doi/10.1021/...

Mitigating Ion Migration with Alternating Voltage for Stable Perovskite Image Sensors Perovskite photodetectors have emerged as a potential replacement for silicon photodiodes in modern cameras due to their high sensitivity to visible light and ability to be easily integrated into existing electronics. However, the use of perovskite photodetectors in conventional CMOS image sensors requires the application of reverse bias, which can lead to unstable detector performance due to ion migration effects. In this article, we propose a new approach that involves the application of forward voltage pulses to attenuate ion migration while still enabling the capture of photocurrent under reverse bias. Our results show that using this technique after each cycle of signal integration allows for stable operation of perovskite photodetectors for over 180 h, while applying a constant reverse bias leads to degradation within just 10 min. Additionally, we demonstrate stable imaging using alternating voltage and 8 × 8 crossbar arrays of perovskite photodetectors.

pubs.acs.org/doi/full/10....

Perovskite‐based time‐domain signal‐balancing LiDAR sensor with centimeter depth resolution In this study, we present a monolithic high-speed perovskite-based photodetector capable of directly sensing the time delay between two light pulses with a temporal resolution of at least 170 ps. Thi...

A new highly relevant application of inorganic lead halide perovskites from our group, as a LIDAR sensor, leveraging their light absorption and defect-tolerant electronic properties, particularly fast photoconductivity transients.
onlinelibrary.wiley.com/doi/10.1002/...

Low-Pressure Cycling of Lithium Metal Anodes with Argyrodite Solid-State Electrolytes Enabled by an Sb-Based Interfacial Layer This study presents a facile and scalable methodology to achieve stable cycling of lithium metal anodes in argyrodite-type Li6PS5Cl (LPSCl)-based soli…

www.sciencedirect.com/science/arti...

solid-state NMR captures much more information about our materials, then we can fully see and comprehend. an everlasting learning curve.

pubs.acs.org/doi/full/10....

Air‐Stable Aluminum Tris[Bis(mesitoyl)Arsenide] Precursor for Metal Arsenide Quantum Dots Aluminum tris[bis(mesitoyl)arsenide]: a new enin metal–arsenide QD synthesis.

8+ years of this project, with long breaks, yielding novel route to InAs QDs.
Such acylpnictide precursors are scalable, inexpensive and versatile.

onlinelibrary.wiley.com/doi/10.1002/...

Dual-Layer Li Metal All-Solid-State Battery Based on an Argyrodite-type Li6PS5Cl Catholyte and a Garnet-type Li7La3Zr2O12 Separator The integration of argyrodite-type Li6PS5Cl (LPSCl) solid-state electrolytes (SSEs) in solid-state batteries faces significant challenges due to their chemical reactivity with lithium metal, which pre...

Our battery folks work only on hard problems - that is all-solid-state batteries. Each such step matters to eventually devise an architecture with good interfaces, practical energy and power densities.
pubs.acs.org/doi/10.1021/...

Organizers @mvkovalenko,Grigorios Itskos & @M_Bodnarchuk kick off #EMLEM25 @nanoGe_Conf with inspiring opening remarks!

Ready to dive into Perovskite, III-V & Zn-Chalcogenide QDs, IR-emissive nanomaterials, Metal Halides and 2D light-emitting materials

🔗https://www.nanoge.org/EMLEM24/home

🙌Following an inspiring morning at #EMLEM25, the community gathered for a group photo.

📸 Excited to explore the latest advances in light-emitting materials and their innovative applications.

Inspiring sessions ahead!

🔗https://www.nanoge.org/EMLEM25/home

This paper concludes the chapter on cationic ligands for perovskite nanocrystals. or not? We will see. It also sorts diverse ligands based on how tightly and how dynamically they bind.

pubs.acs.org/doi/10.1021/...

Characterizing Emerging Detector Materials for Low‐Dose X‐Ray Imaging X-ray medical imaging requires detectors that deliver images at as low as reasonably possible dose. This perspective outlines a universal characterization framework of X-ray imaging detectors, suitab...

In this article, we aim to guide the proper characterization of emerging materials as X-ray detectors, particularly for low-dose imaging applications.
Kudos, in particular, to K.Sakhatskyi and S. Yakunin ,
In partnership with Prof. Jinsong Huang
advanced.onlinelibrary.wiley.com/doi/10.1002/...

Prospects of Nanoscience with Nanocrystals: 2025 Edition Nanocrystals (NCs) of various compositions have made important contributions to science and technology, with their impact recognized by the 2023 Nobel Prize in Chemistry for the discovery and synthesis of semiconductor quantum dots (QDs). Over four decades of research into NCs has led to numerous advancements in diverse fields, such as optoelectronics, catalysis, energy, medicine, and recently, quantum information and computing. The last 10 years since the predecessor perspective “Prospect of Nanoscience with Nanocrystals” was published in ACS Nano have seen NC research continuously evolve, yielding critical advances in fundamental understanding and practical applications. Mechanistic insights into NC formation have translated into precision control over NC size, shape, and composition. Emerging synthesis techniques have broadened the landscape of compounds obtainable in colloidal NC form. Sophistication in surface chemistry, jointly bolstered by theoretical models and experimental findings, has facilitated refined control over NC properties and represents a trusted gateway to enhanced NC stability and processability. The assembly of NCs into superlattices, along with two-dimensional (2D) photolithography and three-dimensional (3D) printing, has expanded their utility in creating materials with tailored properties. Applications of NCs are also flourishing, consolidating progress in fields targeted early on, such as optoelectronics and catalysis, and extending into areas ranging from quantum technology to phase-change memories. In this perspective, we review the extensive progress in research on NCs over the past decade and highlight key areas where future research may bring further breakthroughs.

This monumental effort, undertaken by many outstanding co-authors, including several invited speakers from the Nanax 2023 conference, which we co-organized, is now online.
Special kudos to Maria Ibáñez and her team.

pubs.acs.org/doi/10.1021/...

Energy-Degenerate Photon-Pair Generation from Individual CsPbBr3 Quantum Dots Beyond single-photon emission, generating correlated N-photon bundles, e.g., a photon pair, is essential for various quantum technologies including quantum teleportation and metrology. A widely explored approach exploits the radiative biexciton cascade in individual (mainly epitaxially grown) quantum dots (QDs). Here, we investigate such a cascade in colloidal CsPbBr3 QDs, a scalable and solution-processable quantum-light emitter. By matching their size-dependent biexciton binding energies to their size-independent phonon energies, we demonstrate the generation of time-correlated and energy-degenerate photon pairs in large (>15 nm) QDs. Under pulsed excitation at 4 K, we observe pronounced photon bunching, with a g(2)(0) of up to 7 in Hanbury Brown and Twiss measurements. The excitation-density-dependent bunching is quantitatively reproduced by multicolor numerical calculations, suggesting the cascade involving biexciton and phonon-mediated exciton decay as origin of the photon pair. Our findings provide new insights into energy-degenerate photon-pair generation in these highly engineerable quantum-light emitters, marking important steps toward their application in quantum-information technologies.

Another paper form our team, advancing novel quantum light sources. Single Perovksite QDs can produce not only single photons on demand, but also degenerate photon pairs.
pubs.acs.org/doi/10.1021/...

Critical current density measurements of Li/solid-state electrolyte anodes: Time for a rethink Critical current density (CCD) measurements are widely used to assess the electrochemical performance of Li metal anodes paired with solid-state electrolytes. Nonetheless, the lack of consensus on the...

Critical current density measurements of Li/solid-state electrolyte anodes: Time for a rethink
Please see our article in Matter:
www.cell.com/matter/abstr...

To perspective candidates. The Committee had started the evaluation, but further applications will still be accepted for an equal consideration, at least until September 21st.

Cover Art images from the papers of our team and some great collaborations.
"Green chemistry" has prevailed in recent years

Designer Sulfonium-Based Capping Ligands for Lead Halide Perovskite Nanocrystals The ongoing quest for improved capping ligands for lead halide perovskite nanocrystals (LHP NCs) is fueled by the immense potential of these emitters as classical and quantum light sources. Herein, we...

We continue exploring novel ligands for perovskite nanocrystals. Almost done with cationic ones...

pubs.acs.org/doi/10.1021/...

Bright Monocompound Metal Halide Scintillator for Fast Neutron Radiography Metal halide scintillator, tetraphenylphosphonium manganese bromide (TPP2MnBr4), provides a significant benefit for fast neutron imaging. A fourfold increase in efficiency over traditional zinc sulfi...

In a sandbox filled with luminescent metal halides, creativity never dims.
advanced.onlinelibrary.wiley.com/doi/10.1002/...

Coherent Multi-Dimensional Spectroscopy Reveals Homogeneous Lineshape Dynamics in CsPbBr3 Quantum Dots Lead halide perovskite (LHP) quantum dots (QD) are an attractive material for light emissive applications due to their lattice, which is both dynamically disordered and defect tolerant. The developmen...

pubs.acs.org/doi/full/10....

Stable, Room-Temperature, Low-Threshold Amplified Spontaneous Emission from Thermally Evaporated Cesium Lead Halide Perovskites Semiconductor nanocrystals are widely investigated as tunable quantum emitters due to their composition-, size- and shape-dependent optical properties, and they find applications in various optoelectr...

Stable, Room-Temperature, Low-Threshold Amplified Spontaneous Emission from Thermally Evaporated Cesium Lead Halide Perovskites | ACS Nano

pubs.acs.org/doi/10.1021/...

On the Feasibility of Pairing Pyrochlore Iron(III) Hydroxy Fluoride Cathode with Argyrodite Li6PS5Cl Solid‐State Electrolyte for Low‐Cost All‐Solid‐State Batteries
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/...

Assistant Professor (Tenure Track) of Inorganic Chemistry

ethz.ch/en/the-eth-z...

Only 10 days left!
⏰ @ all supervisors of PhD students in Switzerland. Please see below. And please spread the word.

Our squad of Invited speakers at ICMAT 2025.

Very rarely do materials check all the boxes for a competitive and practical utility as a commercial cathode material for Li-ion batteries. Li-Fe-halides offer this promise, particularly (and uniquely) for all-solid-state batteries. Our recent contribution:
chemrxiv.org/engage/chemr...

Don't miss - already this Monday! Learn about the legacy of the renowned Ukrainian microbiologist - Serhiy Winogradsky (born 1856 in Ukraine, died 1953 in France).
Among other places, he made major discoveries at ETH Zürich. His life for a period was split between Switzerland and Ukraine.

Standardizing XPS and HAXPES Analyses of LLZO Solid-State Electrolytes and Their Reactive Compounds Surface contamination of Li7La3Zr2O12 (LLZO) is a significant challenge that impedes its use as a nonflammable and nontoxic solid-state electrolyte in high energy density, temperature-tolerant Li meta...

A wonderful and fruitful collaboration with Lars Jurgens at Empa.

Standardizing XPS and HAXPES Analyses of LLZO Solid-State Electrolytes and Their Reactive Compounds | ACS Materials Au pubs.acs.org/doi/10.1021/...