Volume 92, Issue 5 - IUPAC-SOLVAY International Award for Young Chemists

Despite rapid advancements in power conversion efficiency in the last decade, perovskite solar cells still perform below their thermodynamic efficiency limits. Non-radiative recombination, in particular, has limited the external radiative efficiency and open circuit voltage in the highest performing devices. We review the historical progress in enhancing perovskite external radiative efficiency and determine key strategies for reaching high optoelectronic quality. Specifically, we focus on non-radiative recombination within the perovskite layer and highlight novel approaches to reduce energy losses at interfaces and through parasitic absorption. By strategically targeting defects, it is likely that the next set of record-performing devices with ultra-low voltage losses will be achieved.

Photoinduced charge generation forms the physical basis for energy conversion in organic photovoltaic (OPV) technology. The fundamental initial steps involved are absorption of light by organic semiconductors (generally π-conjugated polymers) to generate photoexcited states (Frenkel excitons) followed by charge transfer and charge separation processes in presence of suitable acceptor. The absorbed photon energy must be utilized completely for achieving maximum device efficiency. However progressive relaxation losses of instantaneously generated high-energy or hot-excited states form major bottleneck for maximum derivable voltage. This efficiency limiting factor has been challenged recently by the role of hot-carriers in efficient generation of charges. Therefore tailoring the dissociation of hot-exciton to be temporally faster than all relaxation processes could minimize the energy loss pathways. Implementation of this concept of hot-carrier photovoltaics demands critical understanding of molecular parameters that circumvent all energy relaxation processes and favor hot-carrier generation. In my dissertation work, I have examined the fate of photo-generated excitons in the context of polymer backbone and morphology, and therefore obtain a fundamental structure-function correlation in organic semiconductors.

Organic electronics are at the forefront of modern research, with goals of creating more efficient and environmentally benign devices. Organic molecules can achieve this as they typically result in materials that are solution-processable and less toxic than their transition-metal counterparts. Electrochromic molecules have unique color changing properties upon passing an electrical current making them highly sought after for colored displays, dimming mirrors, and smart windows. Part of my PhD work was devoted to developing a new class of electrochromic molecules, the phosphoryl-bridged viologens, with more favorable redox properties and new color changing modes. In order to understand the necessity and potential of new electrochromes, it is important to assess the history of the field and its future. In addition to designing new molecules for electrochromic devices, it is equally important to design a multifunctional species with a bright, competitive future across various organic electronic applications.

Electrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.

Bicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butanes are structurally unique compounds that exhibit diverse chemistry. Bicyclo[1.1.0]butane is a four-membered carbocycle with a bridging C(1)-C(3) bond and 1-azabicyclo[1.1.0]butane is an analog of bicyclo[1.1.0]butane featuring a nitrogen atom at one bridgehead. These structures are highly strained, allowing them to participate in a range of strain-releasing reactions which typically cleave the central, strained bond to deliver cyclobutanes or azetidines. However, despite these molecules being discovered in the 1950s and 1960s, and possessing a myriad of alluring chemical features, the chemistry and applications of bicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butanes remain underexplored. In the past 5 years, there has been a resurgent interest in their chemistry driven by the pharmaceutical industry’s increasing desire for new methods to access cyclobutanes and azetidines. This short review intends to provide a timely summary of the most recent developments in the chemistry of bicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butane to highlight the diverse chemistry they can access, their value as synthetic precursors to cyclobutanes and azetidines, and to identify areas for future research.

This short review summarizes our recent progress in fiber-shaped lithium-ion batteries and lithium-air batteries based on carbon nanotube hybrid fiber electrodes. The fiber architecture allows batteries to be deformable in all dimensions and bear various deformations such as bending, tying, twisting and even stretching. They are scaled up and further woven into breathable, flexible, stretchable and shape-memory textiles to effectively meet the requirements of modern electronics such as wearable products.

In this short review, different phenomena that are triggered by the interaction of different compounds or clusters of compounds with electron-deficient systems, in particular beryllium and boron compounds, have been discussed in some detail. Particular attention was devoted to the huge acidity enhancements that can be induced through the interaction of conventional bases with B or Be containing compounds, which change these conventional bases in extremely strong proton donors. We have paid also attention to the cooperativity between Be bonds with other weak interactions, which results in a substantial increase of their strength, that can lead in some specific cases to the spontaneous formation of ion-pairs in the gas phase. Finally, the behavior of different Be derivatives as electron and anion sponges is discussed as well as the conditions needed to have clusters exhibiting rather strong Be–Be bonds, even though the Be–Be interaction in Be 2 dimer is extremely weak. Finally, some attention was paid to systems with extremely short Be–Be distances but without a bond.

I am a professor at Chalmers University of Technology in Sweden. I trained in chemistry in Sweden but went to the USA for my postdoc. I remained there for 12 years, being faculty at two American universities, before I returned to Sweden for a professorship in the northern city of Umeå. More recently, I returned to my alma mater Chalmers University of Technology in Gothenburg, where I have taken on senior leadership roles. On paper, my career trajectory looks straightforward, but there are many detrimental aspects and lucky coincidences that are not listed on my CV. Life in academia is never easy, and one is never ‘done’. But working in academia is wonderful, as it provides so much freedom and creativity, including being very accommodating towards having kids. Here, I will describe my own personal journey, with the hope of inspiring young women to follow their own path in academia. Yes, there is still bias against women in academia, but change is happening, and the many benefits of being an academic beat such drawbacks.

This brief Technical Report summarizes the key points on the nomenclature of macromolecules and polymers.