Mihai Irimia-Vladu

• Ph.D.
• Joanneum Research

The cover image is based on the article Natural polymers for emerging technological applications: cellulose, lignin, shellac and silk by Mihai Irimia‐Vladu et al., https://doi.org/10.1002/pi.6697 . image

Three natural alkaloids: caffeine, theobromine and theophylline are reported for their application as dielectric layers in organic field effect transistors (OFETs) utilizing both gold and aluminum gate electrodes. After careful purification of the materials, a detailed analysis using x-ray diffraction spectroscopy (XRD), Fourier transform infrared...

In an effort to stave off the growth of electronic waste (e‐waste) that poses a critical environmental dilemma, scientists often look into nature as an unending inspirational pool of materials and chemical processes that ensure functionality, performance and safe dissolution at the end of life cycle. This short review highlights only four organic p...

Sepia melanin, a biopigment extracted from the ink sac of cuttlefish, is relevant to sustainable organic electronics. In this work, we flexographically print films from an ink of Sepia melanin including shellac as a bio-sourced binder on silver electrode-patterned paper. We examine the electrical response in high humidity and ambient conditions (he...

Correction for ‘N,N′-Substituted quinacridones for organic electronic device applications’ by Donia Saadi et al., Mater. Adv., 2023, 4, 2214–2225, https://doi.org/10.1039/D2MA01010K.

A group of industrial vat orange dyes i.e. vat orange 1, vat orange 3 and vat orange 9 are investigated for their suitability as semiconductors in organic field effect transistors.

Hydrogen peroxide (H2O2) is identified as a promising reagent for fuel cells, reducing the dependency on carbon‐based fuels. In this work, electrochemically synthesized polymers are employed to improve the efficiency of the oxygen (O2) reduction reaction, thus producing H2O2 in an environmentally friendly way. Two aminoanthraquinones, as well as ri...

We demonstrate in this work the practical use of uniform mixtures of a bioresin shellac and four natural clays, i.e. montmorillonite, sepiolite, halloysite and vermiculate as dielectrics in organic field effect transistors (OFETs). We present a thorough characterization of their processability and film forming characteristic, surface characterizati...

Four pinaceae pine resins analyzed in this study: black pine, shore pine, Baltic amber, and rosin demonstrate excellent dielectric properties, outstanding film forming, and ease of processability from ethyl alcohol solutions. Their trap‐free nature allows fabrication of virtually hysteresis‐free organic field effect transistors operating in a low v...

N,N′-Substituted quinacridones are a novel class of commercially available quinacridones for organic electronics which are reported here. In this study, we performed in-depth investigations of the material properties of these molecules i.e. their optical and charge transport properties, infrared-active vibrations (FTIR), electrochemical reduction a...

When studying electrochemical oxygen reduction reactions in homogeneous media, special attention must be given to the significant background activity present with conventional electrode materials. The intrinsic electrocatalytic activity of different materials can be investigated using complementary methods, such as the rotating ring-disc electrode...

Organic Electronics In article number 2200285, Mihai Irimia-Vladu, Alessandra Operamolla and co-workers demonstrate the successful use of kraft lignin, the waste biopolymer produced by pulp mills, as the dielectric material for organic field effect transistors. This work represents an example of a circular economy applied to organic electronics.

Lignin is an abundant biopolymer deriving from industrial pulping processes of lignocellulosic biomass. Despite the huge amount of yearly produced lignin waste, it finds scarce application as a fine material and is usually destined to be combusted in thermochemical plants to feed, with low efficiency, other industrial processes. So far, the use of...

Natural Dielectric Materials In article 2200234, Mihai Irimia‐Vladu and co‐workers demonstrate that the naturally occurring Pinaceae fir resins nuggets, originating from the trees growing in Europe and North America, as excellent dielectric materials for devices fabrication in the frame of sustainable electronics development, given their outstandin...

Electrochemical capture of carbon dioxide (CO2) using organic quinones is a promising and intensively studied alternative to the industrially established scrubbing processes. While recent studies focused only on the influence of substituents having a simple mesomeric or nucleophilicity effect, we have systematically selected six anthraquinone (AQ)...

Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach ha...

Natural dielectrics are emerging nowadays as a niche selection of materials for applications targeting biocompatibility and biodegradability for electronics and sensors within the overall effort of scientific community to achieve sustainable development and to build environmental consciousness. The two natural resins analyzed in this study, silver...

Anthraquinone (AQ) has long been identified as a highly promising lead structure for various applications in organic electronics. Considering the enormous number of possible substitution patterns of the AQ lead structure, with only a minority being commercially available, a systematic experimental screening of the associated electrochemical potenti...

A thorough material characterization of 1,7‐diazaperylene via multiple investigation techniques (cyclic voltammetry, photoluminescence, photoluminescence excitation, impedance spectroscopy) was performed to understand its applicability in organic electronic devices. The recorded data of this perylene derivative was placed in conjunction with the re...

Stable cesium lead bromide perovskite nanocrystals (NCs) showing near-unity photoluminescence quantum yield (PLQY), narrow emission profile, and tunable fluorescence peak in the green region can be considered the ideal class of nanomaterials for optoelectronic applications. However, a general route for ensuring the desired features to the perovskit...

Organic semiconductors offer great promise through their ease of synthesis in a multitude of derivatives, their low temperature processability and their amenability for fabrication of flexible, stretchable and conformable, even imperceptible devices. Nevertheless, the low charge mobility of organic semiconductors remains one of the limiting factors...

The electronics era is flourishing and morphing itself into Internet of Everything, IoE. At the same time questions arise on the issue of electronic materials employed: especially their natural availability and low cost fabrication, their functional stability in devices, and finally their desired biodegradation at the end of the life cycle. Hydroge...

With the advent of the Internet of Everything (IoE) era, our civilization and future generations will employ an unimaginable complex array of electronics and sensors in daily life. Ferroelectric polymers represent a core group of materials supporting the fast development of IoE, and their functionality, straightforward processing and unmatched vers...

Robust organic thin-film transistors (OTFTs) with high temperature stability allow device integration with mass production methods like thermoforming and injection molding, and enable operation in extreme environment applications. Herein we elaborate a series of materials to make suitable gate dielectric and active semiconductor layers for high tem...

Among the living organisms that have developed very complex photonic architectures, diatoms appear particularly attractive for possible applications in materials science. This chapter reports some significant results in the use of nanostructured biosilica from diatoms microalgae as a versatile source of smart nanomaterials for diverse applications...

In particular conjugated polymers (CPs) combine the outstanding mechanical properties and simple processing technologies typical of plastic with the optoelectronic properties of semiconductors. Finally, CPs are able to conduct both electrons and ions and form stable interfaces with water, opening a new communication channel between electronics and...

This chapter provides a brief overview on "green" materials for degradable circuit boards and organic electronics, including the latest developments in the field. Paper electronics is continuously drawing attention in the scientific community. Paper opens the door to low-cost disposable electronics. Owing to its biodegradability and biocompatibilit...

Photosynthetic bacteria and green plants have evolved photosynthetic pigments and proteins capable of harnessing light and transducing the energy to chemical potential. These include the light-harvesting complex II (LHCII) protein and its associated chlorophylls, as well as the proteins of the photosystem II (PSII) reaction center. Where LHCII is t...

Conventional electronic devices have evolved from the first transistors introduced in the 1940s to integrated circuits and today's modern (CMOS) computer chips fabricated on silicon wafers using photolithography. This chapter reviews such iontronic devices for signal translation and their application in bioelectronics. It begins with a brief descri...

This chapter provides an introduction to different types of organic thin-film transistors (OTFTs) and their working principle. It refers to the architectures proposed for fabricating OTFT sensors and the protocols adopted for realizing sensing measurements. The chapter emphasizes the most recent advances in the field of OTFT sensors in terms of dev...

This chapter describes the approaches for conducting polymer device fabrication, with a particular emphasis on high-throughput, cost-effective, and simple fabrication techniques, applicable to polymers. It focuses on polymer-friendly photolithography and a printing patterning technique. The chapter further focuses on specific characteristics of pri...

This chapter reviews the recent advances in achieving green electronics using cellulosic paper and fibers as a substrate for electronics. It focuses on the paper substrate, individual component development, and the use of paper for sensing purposes in both analytical and point-of-care applications. While using paper as a substrate is difficult, sin...

Transient electronics can be broadly defined as a new class of technology whose defining characteristic is the ability to physically disappear, in whole or in part, at some programmed rate or triggered time, via any of a range of different possible mechanisms including hydrolysis, dissolution, corrosion, de-polymerization, or disintegration. This c...

In this work, we explored industrially relevant pigments quinacridones as organic semiconductors with respect to their applicability in air-stable homojunction (single material-single layer) organic photovoltaic cells. We studied quinacridone and two linear transquinacridones, i.e., Pigment Red 122 (2,9′-dimethylquinacridone) and Pigment Red 202 (2...

Biosensors are electronic devices, where a bio-receptor (an enzyme, an antibody or a nucleic acid) is interfaced with physiochemical transducers, which are used to detect various types of analytes. These smart devices, capable of rapid screening of biological samples, have a high impact not only in point-of-care applications but also in various ana...

Thin film electronics fabricated with non-toxic and abundant materials are enabling for emerging bioelectronic technologies. Herein complementary-like inverters comprising transistors using 6,6′-dichloroindigo as the semiconductor and trimethylsilyl-cellulose (TMSC) films on anodized aluminum as bilayer dielectric layer are demonstrated. The invert...

No abstract is available for this article.

On page 7645, A. Petritz, B. Stadlober, and co-workers demonstrate that the cellulose derivative, trimethylsilyl cellulose, is an excellent choice for the gate dielectric layer of organic field-effect transistors and inverter circuits. The fabricated inverters display extraordinary performance in terms of DC gain, low operational voltage and large...

On page 7645, A. Petritz, B. Stadlober, and co-workers demonstrate that the cellulose derivative, trimethylsilyl cellulose, is an excellent choice for the gate dielectric layer of organic field-effect transistors and inverter circuits. The fabricated inverters display extraordinary performance in terms of DC gain, low operational voltage and large...

"Green" electronics represents not only a novel scientific term but also an emerging area of research aimed at identifying compounds of natural origin and establishing economically efficient routes for the production of synthetic materials that have applicability in environmentally safe (biodegradable) and/or biocompatible devices. The ultimate goa...

We report on the natural source based and biodegradable material cellulose on Al2O3 as ultrathin hybrid high-k dielectric layer for applications in green electronics. Dielectric films of 16 nm cellulose (epsilon approximate to 8.4) and 8 nm Al2O3 (epsilon approximate to 9) exhibit low leakage currents up to electric fields of 1.5 MV/cm. Pentacene a...

Biocompatible and sustainable electronic-grade materials are integral for the development of electronics for biointegration and ‘use-and-throw’ applications. Herein we report the use of the natural resin shellac in organic field-effect transistors. Shellac was employed to cast robust and smooth substrates suitable for durable transistor devices. In...

Hydrogen-bonding (H-bonding) is a relatively strong, highly directional, and specific noncovalent interaction present in many organic molecules, and notably is responsible for supramolecular ordering in biological systems. The H-bonding interactions play a role in many organic electrically conducting materials – in particular in those related to bi...

Extensive intramolecular π-conjugation is considered to be requisite in the design of organic semiconductors. Here, two inkjet pigments, epindolidione and quinacridone, that break this design rule are explored. These molecules afford intermolecular π-stacking reinforced by hydrogen-bonding bridges. Air-stable organic field effect transistors are re...

Perhaps the same materials used in printer inks and hair dyes can be employed in future electronic technologies? The front cover illustrates the use of hydrogen-bonded pigments, well-established printing inks, in organic electronic circuits. On page 1563, Eric Daniel Głowacki and co-workers present a new perspective for the design of stable organic...

Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities-some of which require a paradigm shif...

Biological materials in organic electronics stand for low-cost production of biocompatible, biodegradable, and sustainable electronic devices. In this chapter, we discuss such materials and their implementation in the fabrication of electronic circuits. We briefly introduce applications of such biocompatible and biodegradable materials for interfac...

We describe the history of indigo dye and its derivative Tyrian purple, from their roles in the ancient world to recent research showing the semiconducting properties of indigoids. Indigoids are natural dyes that have been produced for centuries, and indigo is currently the most produced dye worldwide. Herein we review the history of these material...

Quinacridone is a five-ring hydrogen-bonded molecule analogous in structure and size to the well-known organic semiconductor pentacene. Unlike pentacene, quinacridone has limited intramolecular π-conjugation and becomes highly colored in the solid state due to strong intermolecular electronic coupling. We found that quinacridone shows a field-effec...

We live in a world where the lifetime of electronics is becoming shorter, now approaching an average of several months. This poses a growing ecological problem. This brief review will present some of the initial steps taken to address the issue of electronic waste with biodegradable organic electronic materials. Many organic materials have been sho...

We report on the fabrication and performance of vacuum-processed organic field effect transistors utilizing evaporated low-density polyethylene (LD-PE) as a dielectric layer. With C60 as the organic semiconductor, we demonstrate low operating voltage transistors with field effect mobilities in excess of 4 cm2/Vs. Devices with pentacene showed a mob...

The cover shows a stylized electronic circuit in the shape of an indigo molecule embedded in an elastomer. Originally extracted from plants of the Indigofera genus more than 4000 years ago, indigo is nowadays the most industrially produced pigment. On page 375, Mihai Irimia-Vladu and co-workers present a new perspective this molecule brings to the...

Millenniums-old natural dye indigo - a "new" ambipolar organic semiconductor. Indigo shows balanced electron and hole mobilities of 1 × 10(-2) cm(2) V(-1) s(-1) and good stability against degradation in air. Inverters with gains of 105 in the first and 110 in the third quadrant are demonstrated. Fabricated entirely from natural and biodegradable co...

Ambipolar organic semiconductors enable complementary-like circuits in organic electronics. Here we show promising electron and hole transport properties in the natural pigment Tyrian Purple (6,6’-dibromoindigo). X-ray diffraction of Tyrian Purple films reveals a highly-ordered structure with a single preferential orientation, attributed to intermo...

We report on C(60) based organic field effect transistors (OFETs) that are well optimized for low voltage operation. By replacing commonly used dielectric layers by thin parylene films or by utilizing different organic materials like divinyltetramethyldisiloxane-bis(benzocyclo-butene) (BCB), low density polyethylene (PE) or adenine in combination w...

Herein we report our recent efforts in employing natural materials and synthetic derivatives of natural molecules for organic field effect transistors (OFETs) and organic photovoltaics (OPVs). We evaluated dyes from the following chemical families: acridones, anthraquinones, carotenoids, and indigoids. These materials have proven effective in organ...

“Exotic” materials have become the focus of recent developments in organic electronics that envision biocompatibility, biodegradability, and sustainability for low-cost, large-volume electronic components. In this brief review, we discuss firstly the use of paper, leather, silk, hard gelatine, and bio-degradable plastics as substrates for electroni...

A thin film of emeraldine base polyaniline in NMP was cast on an interdigitated electrode and its conductivity was investigated by impedance spectroscopy. The thin film responded to carbonic acid solutions of various pHs lower than 5. In general, an emeraldine base (EB) to emeraldine salt (ES) transformation occurs by protonation when the pH is les...

Biocompatible-ingestible electronic circuits and capsules for medical diagnosis and monitoring are currently based on traditional silicon technology. Organic electronics has huge potential for developing biodegradable, biocompatible, bioresorbable, or even metabolizable products. An ideal pathway for such electronic devices involves fabrication wit...

Biocompatible-ingestible electronic circuits and capsules for medical diagnosis and monitoring are currently based on traditional silicon technology. Organic electronics has huge potential for developing biodegradable, biocompatible, bioresorbable, or even metabolizable products. An ideal pathway for such electronic devices involves fabrication wit...

Environmentally sustainable systems for the design, production, and handling of electronic devices should be developed to solve the dramatic increase in electronic waste. Sustainability in plastic electronics may be the production of electronic devices from natural materials, or materials found in common commodity products accepted by society. Ther...

Two major concerns in the world nowadays are the plastic consumption and waste. Because to the economic growth and the incessant demand of plastics in developing countries, plastics consumption is projected to increase by a factor of two to three during the actual decade1. As an intuitive example, the amount of municipal solid waste (estimated per...

The transfer of benchtop knowledge into large scale industrial production processes represents a challenge in the field of organic electronics. Large scale industrial production of organic electronics is envisioned as roll to roll (R2R) processing which nowadays comprises usually solution-based large area printing steps. The search for a fast and r...

The development of evaporation processed and C60 organic field effect transistors (OFETs), with insulating polyaniline evaporated from precursor emeraldine base was investigated. Transistors were built on 1.5 × 1.5 cm2 glass slides. Bottom gate aluminum electrodes were thermally evaporated through a patterned mask. The ITO gate electrodes were patt...

Devices with C60 as the organic semiconductor and poly(vinyl alcohol) (PVA) as the gate dielectric was investigated in order to show the importance of mobile ionic impurities. A dialysis tubing was filled with a solution of electronic-grade PVA and submerged into 18 MΩ water at room temperature for about 24 hours. Atomic absorption spectroscopy (AA...

Poly(vinyl alcohol) (PVA) is a water based dielectric often used as a coating layer in paper industry. Due to its water solubility PVA is also interesting as gate insulator in organic field effect transistors. Depending on the preparation of the PVA gate, transistors with and without hysteresis can be produced, with applications in organic electron...

A CO2 sensor based on a composite thin film of emeraldine base polyaniline and poly (vinyl alcohol) cast from N-methyl pyrrolidone on an interdigitated electrode was characterized using impedance spectroscopy. The response of the sensor was slow and smaller in magnitude as compared to reports in the literature for similar sensors. Materials charact...

The conductivity of an emeraldine base polyaniline thin film on an interdigitated electrode in hydrochloric acid solutions of various pHs between 2.25 and 6 was investigated by impedance spectroscopy. In general, protonation induces an emeraldine base (EB) to emeraldine salt (ES) transformation and an associated increase in conductivity only when t...

Introduction Respiration, or CO 2 evolution, is a universal indicator for biological activity, so determination of CO 2 evolution is useful for many biological applications. Over the years, measurement of CO 2 evolution rate has been used for studying living microbial biomass in soils, pesticide damage on soil microorganisms, decomposition of leaf...