Jovana V. Milic

Université de Fribourg · Adolphe Merkle Institute

The industrialization of perovskite solar cells requires adequate materials and processes to make them economically viable and environmentally sustainable. Despite promising results in terms of power conversion efficiency and operational stability, several hole‐transport layers currently in use still need to prove their industrial feasibility. This...

Metal halide perovskites have become one of the leading semiconductors for new-generation photovoltaics. However, their application is limited by the instabilities against the environmental conditions, i.e., oxygen and water, as well as exposure to voltage bias and light. This is related to degradation processes involving ion migration, particularl...

Host‐guest complexation has demonstrated potential for controlling hybrid organic‐inorganic metal halide perovskite materials. In particular, crown ethers have been used due to their capacity to interact with metal cations (e.g. Pb2+) and small organic cations (e.g. methylammonium (MA)), which can affect hybrid perovskite materials and their solar...

The instability of hybrid organic-inorganic halide perovskites presents one of the pressing challenges for their application. This is associated with the sensitivity to moisture as well as mixed ionic-electronic conductivity that leads to enhanced ion migration under conditions of voltage and light bias. Some of the most effective strategies to sta...

2D halide perovskites feature a versatile structure, which not only enables the fine‐tuning of their optoelectronic properties but also makes them appealing as model systems to investigate the fundamental properties of hybrid perovskites. In this study, the authors analyze the changes in the optical absorption of 2D Dion‐Jacobson mixed halide perov...

Layered Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) hybrid perovskite are promising materials for optoelectronic applications due to their modular structure. To fully exploit their functionality, mechanical stimuli could be used to control their properties without changing the composition. However, the responsiveness of these systems to pressure...

Layered Hybrid Perovskites Mechanical pressure can be a tool for tailoring optoelectronic properties of layered hybrid perovskites without changing their composition. In article number 2108720, Bruno Ehrler, Jovana V. Milić, and co‐workers demonstrate that Dion–Jacobson and Ruddlesden–Popper perovskites based on 1,4‐phenylenedimethylammonium and be...

Layered hybrid perovskites are based on organic spacers separating hybrid perovskite slabs. We employ arene and perfluoroarene moieties based on 1,4-phenylenedimethylammonium (PDMA) and its perfluorinated analogue (F-PDMA) in the assembly of hybrid layered Dion-Jacobson perovskite phases. The resulting materials are investigated by X-ray diffractio...

Predicting the performance of solar cells though analytical models is important for the theory-guided optimization of these devices. Earlier models neglect the impact of the optical generation in the quasi-neutral regions of a perovskite solar cell. Here, a new model is developed that takes optical generation in these regions into account. The mode...

Dion–Jacobson (DJ) iodoplumbates based on 1,4-phenylenedimethanammonium (PDMA) have recently emerged as promising light absorbers for perovskite solar cells. While PDMA is one of the simplest aromatic spacers potentially capable of forming a DJ structure based on (PDMA)An−1PbnI3n+1 composition, the crystallographic proof has not been reported so fa...

One of the most prominent hole‐transporting material (HTM) for hybrid perovskite solar cells has been 2,2″,7,7″‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (spiro‐OMeTAD), which is commonly doped with metal bis(trifluoromethylsulfonyl)imide (M(TFSI)n) salts that contribute to generating the active radical cation HTM species. The und...

Layered hybrid perovskites (LHPs) have recently emerged as attractive materials in optoelectronics, particularly due to higher environmental and operational stabilities as compared to their three-dimensional metal-halide perovskite analogues. These materials are based on hybrid halide perovskite layers templated by organic moieties that connect adj...

Mechanical reliability of perovskite solar cells is an important factor in ensuring their operational stability, yet it remains a critical challenge. Researchers have now demonstrated that interfacial self-assembled monolayers increase adhesion toughness between the perovskite and charge-transport layers, enhancing the device stability.

There is an ongoing surge of interest in the use of formamidinium (FA) lead iodide perovskites in photovoltaics due to their exceptional optoelectronic properties. However, thermodynamic instability of the desired cubic perovskite (α-FAPbI3) phase at ambient conditions leads to the formation of a yellow non-perovskite (δ-FAPbI3) phase that compromi...

Two-dimensional (2D) halide perovskites feature a versatile structure, which not only enables the fine-tuning of their optoelectronic properties but also makes them appealing as model systems to investigate the fundamental properties of hybrid perovskites. In this study, we analyzed the changes in the optical absorption of 2D Dion-Jacobson mixed ha...

Formamidinium lead iodide perovskites are promising light-harvesting materials, yet stabilizing them under operating conditions without compromising optimal optoelectronic properties remains challenging. We report a multimodal host–guest complexation strategy to overcome this challenge using a crown ether, dibenzo-21-crown-7, which acts as a vehicl...

The commercialization of perovskite solar cells is mainly limited by their operational stability. Interlayer modification by thin interface materials between the perovskite and the charge transport layers is one of the most effective methods to promote the efficiency and stability of perovskite devices. However, the commonly used interlayer materia...

p>The commercialization of perovskite solar cells is mainly limited by their operational stability. Interlayer modification by thin interface materials between the perovskite and the charge transport layers is one of the most effective methods to promote the efficiency and stability of perovskite devices. However, the commonly used interlayer mater...

Photoluminescence (PL) spectra of atomically thin 2D lead iodide perovskite films are shown to depend on excited-state density, especially at cryogenic temperatures. At high excited-state densities and low temperatures, free exciton (FE) emission is so suppressed by exciton–exciton annihilation (EEA) that other—normally much weaker—emissions domina...

Global societal challenges emphasize the importance of collaboration between scientists and policy‐makers, while the participation of a diverse group of professionals, including early‐career scientists, is critical towards a sustainable future. The European Young Chemists’ Network (EYCN) has been actively working with the European Chemical Society...

Over the past three decades, dye‐sensitized solar cells (i. e. Grätzel cells) have evolved from a pioneering concept of molecular photovoltaics to large‐scale industrial deployment. In this review article, we provide a historical overview of the developments with a focus on the scientific advancements that have set the stage for this technology to...

Hybrid halide perovskites feature mixed ionic-electronic conductivities that are enhanced under device operating conditions. This has been extensively investigated over the past years by a wide range of techniques. In particular, the suppression of ionic motion by means of material and device engineering has been of increasing interest, such as thr...

The use of layered perovskites is an important strategy to improve the stability of hybrid perovskite materials and their optoelectronic devices. However, tailoring their properties requires accurate structure determination at the atomic scale, which is a challenge for conventional diffraction-based techniques. We demonstrate the use of nuclear mag...

This editorial provides suggestions on scientific writing from the perspective of early-career chemists to facilitate the writing process and provides relevant resources for early-career researchers in preparing their first manuscripts.

Layered hybrid halide perovskites are known to be more environmentally stable than their 3D analogues. The enhanced stability is particularly relevant for Dion-Jacobson-type layered perovskites due to their promising photovoltaic performances. However, in contrast to the expected resilience to moisture, we reveal that the structure of Dion-Jacobson...

The use of molecular modulators to reduce the defect density at the surface and grain boundaries of perovskite materials has been demonstrated to be an effective approach to enhance the photovoltaic performance and device stability of perovskite solar cells. Herein, we employ crown ethers to modulate perovskite films, affording passivation of under...

Layered hybrid perovskites have emerged as a promising alternative to stabilizing hybrid organic–inorganic perovskite materials, which are predominantly based on Ruddlesden‐Popper structures. Formamidinium (FA)‐based Dion‐Jacobson perovskite analogs are developed that feature bifunctional organic spacers separating the hybrid perovskite slabs by in...

Layered hybrid perovskites comprising adamantyl spacer (A) cations based on the A2FAn–1PbnI3n+1 (n = 1–3, FA = formamidinium) compositions have recently been shown to act as promising materials for photovoltaic applications. While the corresponding perovskite solar cells show performances and stabilities that are superior in comparison to other lay...

There has been an ongoing effort to overcome the limitations associated with the stability of hybrid organic-inorganic perovskite solar cells by using different organic agents as additives to the perovskite formulations. The functionality of organic additives has been predominantly limited to exploiting hydrogen-bonding interactions, while the rele...

Formamidinium (FA) lead iodide perovskite materials feature promising photovoltaic performances in conjunction with superior thermal stabilities. However, the conversion of the perovskite α‐FAPbI 3 phase to the thermodynamically stable yet photovoltaically inactive δ‐FAPbI3 phase compromises the photovoltaic performances of the corresponding solar...

Formamidinium (FA) lead iodide perovskite materials feature promising photovoltaic performances in conjunction with superior thermal stabilities. However, the conversion of the perovskite α‐FAPbI 3 phase to the thermodynamically stable yet photovoltaically inactive δ‐FAPbI3 phase compromises the photovoltaic performances of the corresponding solar...

Over the past decade, we witnessed a remarkable development of a new generation of photovoltaic technologies, in particular dye-sensitized and perovskite solar cells. These systems have demonstrated potential to provide solutions for a more sustainable future in energy conversion. Both of these technologies, however, still encounter a number of cha...

Chemical doping of inorganic-organic hybrid perovskites is an effective way of improving the performance and operational stability of perovskite solar cells (PSCs). Here we use 5-ammonium valeric acid (AVAI) to chemically stabilize the structure of α-FAPbI3. Using solid-state MAS NMR, we demonstrate the atomic-level interaction between the molecula...

Preventing the degradation of metal perovskite solar cells (PSCs) by humid air poses a substantial challenge for their future deployment. We introduce here a two-dimensional (2D) A2PbI4 perovskite layer using pentafluorophenylethylammonium (FEA) as a fluoroarene cation inserted between the 3D light-harvesting perovskite film and the hole-transporti...

Nanoscale machines have inspired the search for molecular grippers, and the effort has been expedited by the development of redox‐active, quinone‐based resorcin[4]arene cavitands. The article describes the breakthroughs in the design and control of resorcin[4]arenes by electronic and electromagnetic stimuli using various electroanalytical, spectros...

The quest for nanoscale molecular machines has inspired the search for their close relatives, molecular grippers. This path was paved by the development of resorcin[4]arene cavitands and their quinone‐based redox‐active congeners. In this Concept article, the efforts to design and establish the control of quinone‐functionalized resorcin[4]arenes by...

A key feature of resorcin[4]arene cavitands is their ability to switch between a closed/contracted (Vase) and an open/expanded (Kite) conformation. The mechanism and dynamics of this interconversion remains, however, elusive. In the present study, the Vase‐Kite transitions of a quinoxaline‐based and of a dinitrobenzene‐based resorcin[4]arene are in...

Hybrid organic–inorganic perovskites have become one of the leading thin-film semiconductors for optoelectronics. Their broad application will greatly depend on overcoming the key obstacles associated with poor stability and limited scalability. There has been an ongoing effort to diminish some of these limitations by using organic additives. Howev...

The control of molecular systems by electrical charge or light is a prerequisite for their application in nanoelectronics. Such potential has been uniquely exploited in quinone-based resorcin[4]arene cavitands that can act as molecular grippers, reversibly expanding and contracting in response to electrical or electromagnetic stimuli. The developme...

The utility of molecular actuators in nanoelectronics requires activation of mechanical motion by electric charge at the interface with conductive surfaces. We functionalized redox‐active resorcin[4]arene‐quinone cavitands with thioethers as surface‐anchoring groups at the lower rim and investigated their propensity to act as electroswitchable actu...

Three-dimensional (3D) perovskite materials display remarkable potential in photovoltaics owing to their superior solar-to-electric power conversion efficiency, with current efforts focused on improving stability. Two-dimensional (2D) perovskite analogues feature greater stability toward environmental factors, such as moisture, owing to a hydrophob...

Chalcogen bonding (CB) is the focus of increased attention for its applications in medicinal chemistry, materials science, and crystal engineering. However, the origin of sulfur's recognition properties remains controversial, and experimental evidence for supporting theories is still emerging. Here, a comprehensive evaluation of sulfur CB interacti...

Perovskite solar cells present one of the most prominent photovoltaic technologies, yet their stability, scalability, and engineering at the molecular level remain challenging. We demonstrate a concept of multifunctional molecular modulation of scalable and operationally stable perovskite solar cells that exhibit exceptional solar-to-electric power...

Perovskite solar cells present one of the most prominent photovoltaic technologies, yet their stability, scalability, and engineering at the molecular level remain challenging. We demonstrate a concept of multifunctional molecular modulation of scalable and operationally stable perovskite solar cells that exhibit exceptional solar-to-electric power...

The efficiency of perovskite solar cells (PSCs) is currently limited by non-radiative recombination losses. One potential loss channel consists of electrons recombining at the interface with the hole transport layer (HTL). We synthesized adamantylammonium halides (ADAHX, X = Cl–, Br−, I–) and demonstrated that ADAHI interacts with the perovskite su...

We present an investigation of the photocyclization of novel aromatic diarylethene (DAE) systems 1−3 based on pyrazine, quinoxaline, and helicene scaffolds. These prospective photoswitches were designed using density functional theory calculations and analyzed in solution and in the solid state by cyclic and rotating disk voltammetry, UV−vis and tr...

A light-actuated resorcin[4]arene cavitand equipped with two quinone (Q) and two opposite Ru(II)-based photosensitizing walls was synthesized and investigated. The cavitand is capable of switching from an open to a contracted conformation upon reduction of the two Q to the corresponding SQ radical anions by intramolecular photoinduced electron tran...

One of the most challenging obstacles to commercialization of perovskite solar cells (PSCs) is their instability toward environmental conditions. An emerging solution to overcome these challenges relies on graphene‐based composites, in particular, solution‐processable reduced graphene oxide (rGO), whose high electrical and thermal conductivity, alo...

While metal halide perovskite solar cells (PVSCs) have drawn intense attention due to their high solar-to-power conversion efficiency (PCE), their practical application is hampered by the poor long-term stability against moisture. Although strategies have been reported to solve this issue, these methods are introduced during core-device fabrication...

Semiquinones (SQ) are generated in photosynthetic organisms upon photoinduced electron transfer to quinones (Q). They are stabilized by hydrogen bonding (HB) with the neighboring residues, which alters the properties of the reaction center. We designed, synthesized, and investigated resorcin[4]arene cavitands inspired by this function of SQ in natu...

The development of semiquinone-based resorcin[4]arene cavitands expands the toolbox of switchable molecular grippers by introducing the first paramagnetic representatives. The semiquinone (SQ) states were generated electrochemically, chemically, and photochemically. We analyzed their electronic, conformational, and binding properties by cyclic volt...

Various H-bond acceptor groups were evaluated for their propensity to induce conformational switching between the kite and vase forms of diquinone-diquinoxaline resorcin[4]arene cavitands upon redox interconversion. The H-bond acceptors were placed on the quinoxaline walls with the purpose of stabilizing the vase form only in the reduced hydroquino...