Search

Light-driven modulation of neuronal activity at high spatial-temporal resolution is becoming of high interest in neuroscience. In addition to optogenetics, nongenetic membrane-targeted nanomachines that alter the electrical state of the neuronal membranes are in demand. Here, we engineered and characterized a photoswitchable conjugated compound (BV-1) that spontaneously partitions into the neuronal membrane and undergoes a charge transfer upon light stimulation. The activity of primary neurons is not affected in the dark, whereas millisecond light pulses of cyan light induce a progressive decrease in membrane resistance and an increase in inward current matched to a progressive depolarization and action potential firing. We found that illumination of BV-1 induces oxidation of membrane phospholipids, which is necessary for the electrophysiological effects and is associated with decreased membrane tension and increased membrane fluidity. Time-resolved atomic force microscopy and molecular dynamics simulations performed on planar lipid bilayers revealed that the underlying mechanism is a light-driven formation of pore-like structures across the plasma membrane. Such a phenomenon decreases membrane resistance and increases permeability to monovalent cations, namely, Na+, mimicking the effects of antifungal polyenes. The same effect on membrane resistance was also observed in nonexcitable cells. When sustained light stimulations are applied, neuronal swelling and death occur. The light-controlled pore-forming properties of BV-1 allow performing "on-demand" light-induced membrane poration to rapidly shift from cell-attached to perforated whole-cell patch-clamp configuration. Administration of BV-1 to ex vivo retinal explants or in vivo primary visual cortex elicited neuronal firing in response to short trains of light stimuli, followed by activity silencing upon prolonged light stimulations. BV-1 represents a versatile molecular nanomachine whose properties can be exploit

Molecular doping is pivotal to improve charge transport properties of organic semiconductors. With respect to the p-type counterpart, n-type doping is more challenging, due to the air sensitivity of the required electron rich dopants. The use of kinetically stabilized dopants precursors showed to be an efficient strategy to circumvent this issue. Among these, the benzimidazoline derivative N-DMBI-H is one of the most widely used, but its scarce miscibility within the semiconductors matrix limits its doping efficiency. The research for new benzimidazoline based dopants with improved performances has thus emerged. In this work, we study the doping of the n-type polymer P(NDI2OD-T2) with a set of new N-DMBI-H-like dopants bearing different molecular functionalization patterns. By combining optical and electrical characterization, we analyse the influence of the introduced structural modifications on the compounds performances. Via morphological characterization, we then reveal a relation between the efficiency of the analysed dopants and their solid-state interactions with the semiconductor host, highlighting that the most performing dopants are those characterized by improved intercalation in the semicrystalline polymeric microstructure and lower tendency to segregation. Our results are supported by computational studies and can help in the definition of design guidelines for more performing benzimidazoline based n-type dopants.

Cities and other human settlements are major contributors to climate change and are highly vulnerable to its impacts. They are also uniquely positioned to reduce greenhouse gas emissions and lead adaptation efforts. These compound challenges and opportunities require a comprehensive perspective on the public policy of human settlements. Drawing on core literature that has driven debate around cities and climate over recent decades, we put forward a set of boundary objects that can be applied to connect the knowledge of epistemic communities and support an integrated urbanism. We then use these boundary objects to develop the Goals-Intervention-Stakeholder-Enablers (GISE) framework for a public policy of human settlements that is both place-specific and provides insights and tools useful for climate action in cities and other human settlements worldwide. Using examples from Berlin, we apply this framework to show that climate mitigation and adaptation, public health, and well-being goals are closely linked and mutually supportive when a comprehensive approach to urban public policy is applied.

Photodynamic inhibition (PDI) of bacteria represents a powerful strategy for dealing with multidrug-resistant pathogens and infections, as it exhibits minimal development of antibiotic resistance. The PDI action stems from the generation of a triplet state in the photosensitizer (PS), which subsequently transfers energy or electrons to molecular oxygen, resulting in the formation of reactive oxygen species (ROS). These ROS are then able to damage cells, eventually causing bacterial eradication. Enhancing the efficacy of PDI includes the introduction of heavy atoms to augment triplet generation in the PS, as well as membrane intercalation to circumvent the problem of the short lifetime of ROS. However, the former approach can pose safety and environmental concerns, while achieving stable membrane partitioning remains challenging due to the complex outer envelope of bacteria. Here, we introduce a novel PS, consisting of a metal-free donor-acceptor thiophene-based conjugate molecule (BV-1). It presents several advantageous features for achieving effective PDI, namely: (i) it exhibits strong light absorption due to the conjugated donor-acceptor moieties; (ii) it exhibits spontaneous and stable membrane partitioning thanks to its amphiphilicity, accompanied by a strong fluorescence turn-on; (iii) it undergoes metal-free intersystem crossing, which occurs preferentially when the molecule resides in the membrane. All these properties, which we rationalized via optical spectroscopies and calculations, enable the effective eradication of Escherichia coli, with an inhibition concentration that is below that of current state-of-the-art treatments. Our approach holds significant potential for the development of new PS for controlling bacterial infections, particularly those caused by Gram-negative bacteria.

Luminescent solar concentrators (LSCs) are rapidly emerging as the key enabling technology towards the realization of zero-energy buildings. The development of new efficient and sustainable luminophores is crucial for further improvement. The large Stokes shift, luminescent and persistent radicals prepared using sustainable routes offer advantages for large-area transparent LSCs featuring minimal colour distortion of the transmitted light. LSCs based on the best performing luminescent radicals are largely unaffected by reabsorption losses, thus providing a better performance with respect to the literature standards over active areas exceeding 400 cm2.

Luminescent solar concentrators (LSCs) are becoming an increasingly relevant topic for building integrated photovoltaics. Even if such devices are relatively simple planar waveguides doped with a luminescent material, the achievement of relevant efficiencies requires a careful optimisation of both the matrix and the luminophore. Most of the recent literature focuses on the performance, yet the overall sustainability of the strategy is a topic at least as important. In this respect the luminophore plays a crucial role. Suitable materials must feature a near unit emission quantum yield, efficient light harvesting and a large separation between absorption and emission to reduce reabsorption losses. Due to the target application, such materials must also be readily available in large quantities through sustainable processes. Instead of going for performance first and then scaling up/optimising the synthesis, in this paper we offer a reversed perspective. We have first designed and computationally characterised materials having structural features compatible with a green chemistry synthetic approach, namely, micellar catalysis. Later, we have characterised the most promising materials in LSC devices, and we have compared their performance with commercially available, non-green chemistry compliant alternatives having similar spectral features. In the overall, we demonstrate comparable performance, but greatly improved sustainability and scalability. This journal is

This corrigendum resolves an error in figure 17 and clarifies the scope of the cement sector in figure 2. Figure 17 in the original published manuscript depicts a Kaya identity for the agriculture, forestry and other land uses (AFOLU) sector. We unintentionally excluded land-use CO2 emissions from total greenhouse gas (GHG) emissions in this identity, and depicted only agricultural GHG emissions.

The photon upconversion based on sensitized triplet–triplet annihilation (sTTA-UC) is a spin-flip mechanism exploited to recover the energy stored on dark triplet states in conjugated systems. In this process, a high-energy fluorescent singlet is created through the collision and fusion of two low-energy triplets belonging to different diffusing molecules. Its high yield in solution under low excitation intensity and noncoherent light highlighted the huge potential of sTTA-UC to provide a breakthrough in solar technologies. However, its diffusion-limited nature restrains its efficiency in the solid state. To overcome this issue, we propose a single-molecule system that is able to host simultaneously more than one triplet, thus enabling a diffusion-free intramolecular TTA. We obtain the first direct demonstration of intramolecular triplet fusion by tailored photoluminescence spectroscopy experiments, thus opening the way to realize a new family of single-molecule upconverters with huge potential in solar and lighting technologies by accessing the natural triplets’ energy reservoir.

Luminescent solar concentrators (LSCs) have recently emerged as valuable candidates for the realization of aesthetically pleasing solar windows for near-zero-energy consumption buildings. The growing demand by the building-integrated photovoltaic sector is urging the development of sustainable production methods that minimize the use of polluting organic solvents and hazardous materials, while still enabling industrial-grade LSCs. Here, we introduce a new class of benzothieno-benzothiophene (BTBT) derivatives as highly efficient reabsorption-free emitters for transparent LSCs featuring high stability and a solvent-free chemical access with sustainability factor as low as 21, 10 to 50 times lower than conventional LSC emitters. By embedding our BTBT emitters in optical-grade polymeric waveguides, we produced large-area (40 cm × 40 cm) LSCs with optical power efficiency as high as 3% (corresponding to an optical quantum efficiency of 54%). These results represent an important advancement toward sustainable solar glazing systems for green architecture.The growing demand for building-integrated photovoltaic technologies for near-zero-energy buildings is motivating the scientific community to develop devices that meet the functional, energetic, and aesthetic needs for sustainable architecture. Luminescent solar concentrators (LSCs) are emerging as valuable solutions to realize aesthetically pleasing semitransparent photovoltaic windows capable of converting urban buildings into energy generators. In this work, we report on efficient, transparent LSCs based on a novel class of reabsorption-free derivatives synthesized through a solvent-free route that massively improves the sustainability factor with respect to the state of the art. Optical-grade polymeric LSCs are produced via industrial methods with an optical power efficiency as high as 3% despite their transparency in the visible region. These results represent an important step forward for sustainable solar glazing s