With the rising success of solar photovoltaics, long-term sustainability needs to be addressed. We provide practical steps that researchers, journals and the wider community can take to embed circularity into emerging photovoltaics, from the conception of a new idea, to lab scale demonstrations, to scale-up.

Roll-to-Roll (R2R) deposition offers a promising route for scaling up the production of perovskite solar cells (PSCs); however, the performance of R2R-fabricated devices still lags behind those produced through laboratory-scale methods. One significant factor contributing to this performance gap, particularly in P-I-N structured devices, is the use of suboptimal hole transport layers (HTLs), such as poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT:PSS). In this study, we explore the potential of replacing PEDOT:PSS with poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), a more efficient and stable HTL. While undoped PTAA alone shows promise, its application on the rough surface of PET-ITO substrates is insufficient to fully replace PEDOT:PSS, leading to reduced device performance. However, when combined with a PEDOT:PSS buffer layer, PTAA demonstrated significant improvements, achieving a power conversion efficiency (PCE) of 15.2% compared to 12.6% with PTAA alone using R2R deposition. To better understand the coating characteristics and interactions of these materials, we conducted a detailed analysis of the surface topography of PET-ITO and the HTL layer using X-ray photoelectron spectroscopy (XPS) mapping. This study provides critical insights into the synergistic effects of PEDOT:PSS and PTAA, highlighting their combined potential for enhancing the efficiency of R2R-fabricated PSCs.

In their recent paper in Nature, Gao and colleagues report an aqueous-based recycling process capable of recovering all functional components from thermally degraded perovskite solar cells, including absorber materials, electrodes, and transport layers. Their method regenerates high-purity perovskites from aged devices, enabling new cells with efficiencies exceeding 23%, comparable to pristine devices.

Thanks to their direct band-gap, high absorption coefficient, low manufacturing cost, and relative abundance of component materials, perovskite materials are strong candidates for the next generation of photovoltaic devices. However, their complex photochemistry and photophysics are hindering their development. This is due, in part, to the complex charge carrier recombination pathways in these materials, as well as their instability during measurements. Here, a new characterization methodology is detailed that allows the measurement, with high certainty, of the intrinsic parameters of a single perovskite sample, such as the trap state concentration and carrier mobilities. This methodology is based on a combination of time-resolved microwave photoconductivity (TRMC) and time-resolved photoluminescence (TRPL) spectroscopy. Compared to TRPL only, this methodology is faster, does not lead to significant changes in the perovskite properties over time, and increases the certainty of the parameters retrieved. Using this methodology, green solvent systems are studied to replace the traditional harmful solvents usually used when spin-coating perovskites. Although devices made using the greener solvents presented lower efficiencies, TRMC and TRPL measurements highlighted that the perovskites made with these solvents can achieve the same performance compared to the traditional solvent system.

Synthesis and characterization of new P(III) and P(V) bis(azido)phosphines/phosphoranes supported by an N,N '-bis(2,6-diisopropylphenyl) imidazolin-2-iminato (IPrN) ligand and their reactivity with various secondary and tertiary phosphines result in the formation of chiral and/or asymmetric mono(phosphinimino)azidophosphines via the Staudinger reaction. The reaction of IPrNP(N-3)(2) (2) or IPrNP(S)(N-3)(2) (4S) with an excess of tertiary phosphine resulted in the chemoselective formation of IPrNP(N-3)(NPMe3) (7) or IPrNP(S)N-3(NPR3) (5(R)), respectively. The chemoselective Staudinger reactivity was also observed in reactions using a secondary phosphine (HPCy2) to produce IPrNP(S)N-3[NP(H)Cy-2] (6a), which exists in equilibrium with a tautomeric IPrNP(S)N-3[N(H)PCy2] form (6b), as confirmed by P-31-P-31 nuclear Overhauser effect spectroscopy (NOESY). Density functional theory (DFT) calculations point to a combination of energetically unfavorable lowest unoccupied molecular orbitals (LUMOs) and the accumulation of increasing negative charge at the terminal azido-nitrogen upon a single azide-to-phosphinimine conversion that gave rise to the observed chemoselectivity.

Effective electric energy storage plays a central role in mitigating carbon emissions and other current energy concerns. Hence, this chapter aims to provide an up-to-date discussion on emerging electrode materials for electrochemical capacitors (ECs). The basic concepts, components, fabrication, and electrochemical characterization techniques utilized for ECs are described. In the past, transition metal oxides, particularly RuO2 and MnO2, received significant attention as electrode materials as they have potential to achieve high specific capacitances (Cs) of up to 2200 and 1370 F/g, respectively. Although carbonaceous electrode materials achieve lower Cs (20–300 F/g range) and energy densities (Es) than intrinsic pseudocapacitive materials, they have advantages of natural abundance, low cost, chemical stability, and high conductivity in ECs. The increasing interest in the potential of nanostructured materials in ECs has led to the further development of carbon-based materials. Extrinsic pseudocapacitance can be engineered through decreasing the sizes and nano-structuring of electrode materials. This chapter details the potential opportunities and pitfalls to boost ECs from nano-sizing and nano-structuring of transition metal and carbonaceous materials, and the synergistic effect of nanocomposites due to the enhanced ability to store charge via both intrinsic electrochemical double layer and extrinsic pseudocapacitance effects (from nano-sizing, doping, and introduction of surface functionalities). In summary, the chapter highlights how material science can tailor electrochemical properties and lead to the emergence of new electrode materials with tremendous prospects that promote the sustainability of electrical energy storage systems.

The rapid evolution of perovskite solar cells (PSCs) has positioned this technology as a promising candidate in the global transition towards sustainable energy sources. As the renewable energy sector continues...

Nickel hydroxide has been successfully employed as a precursor to the widely used, inorganic hole transport material (HTM) nickel oxide (NiOx). However, manufacturing NiOx HTM layers from nickel hydroxide is more complicated than those involving organometallic precursors due to its poor solubility/dispersibility. We report here a substantial increase in nickel hydroxide dispersibility in organic solvents by complexing it with monoethanolamine. These improvements have enabled us to develop a simpler method for processing nickel hydroxide that resemble the known sol-gel method. The new metal complex remains dispersed for months and converts to nickel oxide at a temperature similar to that of nickel hydroxide (270-300 degrees C). An extensive characterisation of NiOx films obtained from the deposited precursor has been carried out. Perovskites solar cells have also been built with these films as a proof of concept, showing promising results for the layers sintered at low (270 degrees C) and high (500 degrees C) temperatures. The pixel with highest efficiency for both sintering temperatures were 14.7 % and 16.7 %, respectively, which are close to or surpass the ones of the control samples (15.4 % and 15.7 %, respectively). The applied unpaired t-test statistical method showed that the mean efficiency values for our thick samples prepared at 270 degrees C are not statistically different from those of the control cells. Furthermore, the samples prepared at 500 degrees C presented a significant statistical difference with the control cells, showing higher average efficiencies (12.8 % and 13.3 % versus 11.4 % and 11.7 %, reverse and forward measurements, respectively). The simplicity of the manufacturing method developed, together with the use of non-toxic organic compounds for its preparation and the promising results observed in solar devices, makes it suitable for being upscaled.

Mesoscopic carbon-based perovskite solar cells (CPSCs) are often cited as a potential frontrunner to perovskite commercialization. Infiltration, the extent to which perovskite fills the mesoporous scaffold, is critical for optimum performance and stability. However, infiltration data are usually presented as qualitative photographic comparisons of samples with extreme infiltration variation. This work examines how small infiltration defects impact performance using an optical microscopy examination of the base TiO2 layer to identify issues and develop targeted techniques for infiltration enhancement. Critically, the uninfiltrated area at the base of the stack was found to correlate well with PCE across multiple batches of varied print quality and ZrO2 thickness. Through reduction of mesh mark defects and improvement of print quality in the ZrO2 and carbon layers, a champion PCE of 15.01% is attained. It follows that this facile, multiscaled, nondestructive technique could enable targeted performance enhancement and quality control in future scale-up initiatives.

Renewable materials should be appraised for advancing the sustainability of perovskite solar cells (PSCs). In particular, emerging applications of biologically-derived materials (biomaterials) in PSCs have tremendous potential in enhancing charge transport, device performance, flexibility, long-term stability, sustainability, and circularity strategies. This review discusses the current status and identifies new research directions for biomaterials as either substitutes or composite constituents with other functional materials in charge transport layers and as solvent systems for PSCs. The current understanding of the effect of cellulose on power conversion efficiency (PCE), shape, and long-term stability of PSCs is discussed in terms of surface roughness, wettability, optical properties, defect concentration, and flexibility. Flexible PSCs that utilise biomaterials are advantageous for transportation and widespread implementation, but suffer several other possible adverse effects that lower the PCE due to decreased electron mobility from increased charge traps during bending cycles. Biomaterials have considerable scope in defect passivation, boosting PCE, and long-term stability of PSCs when applied in charge transport layers, particularly as interfacial layers between the electron transport layer and active materials.

Thanks to their high absorption coefficient and ideal band-gap [1], lead halide perovskite materials are good candidates for the next generation of solar cells with an impressive certified power conversion efficiency of >26% [2]. However, the development of perovskite based solar cells is impeded, in some architectures, by obstacles including degradation of the perovskite layer by light, oxygen, and moisture. Photoluminescence (PL) is a measure of photoexcited carrier radiative recombination and is thus a great tool for studying charge carrier processes in solar cells as the later operates through the absorption of light. However, measuring the steady state and time-resolved photoluminescence (PL) of perovskite thin-films is not as straightforward as initially thought, highlighting the sometimes-surprising nature of these materials. [3-5] This has implications for the use of these materials in photovoltaics and LEDs. We will discuss our utilisation of PL studies to understand the stability and performance of perovskite materials. The impact of the incorporation of nanomaterials into perovskite devices will be discussed along with the opportunities and challenges this affords in terms of sustainability and performance. We will discuss the work of The Applied Photochemistry Group at the SPECIFIC Innovation and Knowledge Centre, Swansea University, which aims to develop an understanding of the photostability and photochemistry of materials and devices to advance performance, sustainability, and design for circular economy. Yang, WS; Park, BW; Jung, EH; Jeon, NJ; Kim, YC; Lee, DU; Shin, SS; Seo, J; Kim, EK; Noh, JH; Seok, SI. Science, 2017, 356(6345), 1376-1379. Best Research-Cell Efficiency Chart | Photovoltaic Research | NREL. [Online]. Péan, EV; De Castro, CS; Davies, ML. Materials Letters, 2019, 243, 191-194. Péan, EV; Dimitrov, S; De Castro, CS; Davies, ML. Phys. Chem. Chem. Phys., 2020, 22, 28345-28358. Péan, EV; Davies, ML. J. Chem. Inf. Model. 2023, 63, 15, 4477–4482

Perovskite photovoltaics have shown great promise in device efficiency but also the promise of scalability through solution-processed manufacture. Efforts to scale perovskites have been taken through printable mesoporous scaffolds and slot die coating of flexible substrates roll-to-roll (R2R). However, to date there has been no demonstration of entirely R2R-coated devices due to the lack of a compatible solution-processable back electrode; instead, high-value evaporated metal contacts are employed as a post process. Here, in this study, the combination of a low-temperature device structure and R2R-compatible solution formulations is employed to make a fully R2R printable device architecture overcoming interlayer incompatibilities and recombination losses. Therefore, the n-i-p device structure of SnO2 /perovskite/poly(3,4-ethylenedioxythiophene)/carbon is employed to form an ohmic contact between a p-type semiconductor and printable carbon electrode. In particular, the results show that the small-scale device efficiencies of 13-14% are achieved, matching the device performance of evaporated gold electrodes. Also, this entirely R2R-coated perovskite prototype represents a game changer, reaching over 10% (10.8) stabilized power conversion efficiency with unencapsulated long-term stability retaining 84% of its original efficiency over 1000 h under 70% RH and 25 °C.

Introduction Gold standard treatment for Obstructive Sleep Apnoea (OSA) in paediatrics is adenotonsillectomy (AT). Continuous Positive Airway Pressure (CPAP) is frequently used if AT is not possible or OSA remains unresolved.1 Tolerance of CPAP is challenging in paediatrics. Automatic Positive Airway Pressure (APAP) is a recent ventilator technology enabling automatic adjustment of pressure within specified range in response to events. Case A 16-year-old boy with Crouzon’s syndrome attending for a follow up cardiorespiratory sleep study, after using CPAP for >10 years with good adherence. Prescribed study plan was to start on current 9cmH2O CPAP and follow in-house titration protocol. During this study CPAP was reduced from 9cmH2O to 7cmH2O. Gas exchange was stable and normal across all pressures however signs of obstruction (boxing of respiratory effort and flow limitation) were observed while supine on 7cmH2O. Obstructive respiratory events did not achieve American Academy of Sleep Medicine (AASM) scoring criteria and therefore pressure was not up titrated. APAP was trialled as treatment during a follow-up study four months later. APAP boundaries were prescribed from 5cmH2O to 12cmH2O. Similarly in this study gas exchange was maintained within normal limits. Average pressure overnight was 9cmH2O (7cmH2O in Quiet Sleep and 10cmH2O in Active Sleep). Supine sleep was recorded and there were no underlying signs of obstruction observed. Conclusion These studies illustrate the utility of APAP in paediatrics for treating sub criteria obstructive events when compared with a predetermined manual titration protocol. Future plans are to trial APAP further in selected patient groups and ages. Reference Khaytin I, Tapia IE, Beck SE. J Clin Sleep Med 2020;16(10):1825–1826.

High-temperature treatment increased the conductivity, carrier density and mobility of N-RGO. Inclusion of PANI tailored activities from capacitive to battery-like and diffusion-controlled.

Steroid hormones, being potent endocrine-disruptors, are a menace to human health and aquatic life. Herein, visible-light induced photocatalytic degradation of estrone (E1) by hexagonal copper selenide (CuSe) nanoflakes has been reported. CuSe was synthesised by a facile and low-temperature (100 oC) co-precipitation method and was characterised. The nanocrystals were of stoichiometric Cu:Se ratio with Se2- and Cu in the + 1/+ 2 mixedvalence state and exhibited laminar, flake-like morphology with a preferred hexagonal close-packed structure (P63/mmc) having average particle size and thickness of 0.229 +/- 0.146 mu m and 0.05 +/- 0.02 mu m, respectively. The adsorption isotherms of E1 were linear and the adsorption process was exothermic. The reactivity of E1 under aqueous suspensions of CuSe exposed to visible light exhibited pseudo-first-order kinetics with a rate constant, k, that varied with initial E1 concentration, light power, catalyst dose, and pH. Particularly, k was almost constant over the range pH5-9 but substantially increased as pH rose to 11, while light power and catalyst dose increased k up to a maximum, and the initial concentration reduced k. Surprisingly, CuSe oxidised E1, even in the absence of light, and leached species that were identified and their time-dependency was determined. We concluded that the disappearance of E1 by CuSe is attributed to synergetic effects of adsorption, oxidation by CuSe, and photocatalytic degradation. Supported by liquid-mass spectrometry analysis and molecular chemistry calculations, we also suggested a possible mechanism for E1 degradation. Thus, hexagonal CuSe nanocrystals can be a promising candidate for the treatment of endocrine-disrupting chemicals (EDC)-contaminated wastewaters.

Ruthenium(II) polypyridyl complexes (RPCs) that emit from metal-to-ligand charge transfer (MLCT) states have been developed as DNA probes and are being examined as potential anticancer agents. Here, we report that MLCT-emissive RPCs that bind DNA undergo Fo''rster resonance energy transfer (FRET) with Cy5.5-labeled DNA, forming mega-Stokes shift FRET pairs. Based on this discovery, we developed a simple and rapid FRET binding assay to examine DNA-binding interactions of RPCs with diverse photophysical properties, including non-"light switch" complexes [Ru(dppz)2(5,5 ' dmb)]2+ and [Ru(PIP)2(5,5 ' dmb)]2+ (dppz = dipyridophenazine, 5,5 ' dmb = 5,5 '-dimethyl-2,2 '-bipyridine, PIP = 2-phenyl-imidazo[4,5-f ][1,10]-phenanthroline). Binding affinities toward duplex, G-quadruplex, three-way junction, and mismatch DNA were determined, and derived FRET donor-acceptor proximities provide information on potential binding sites. Molecules characterized by this method demonstrate encouraging anticancer properties, including synergy with the PARP inhibitor Olaparib, and mechanistic studies indicate that [Ru(PIP)2(5,5 ' dmb)]2+ acts to block DNA replication fork progression.

Background Home Sleep Apnoea Testing (HSAT) for the diagnosis of Obstructive Sleep Apnoea (OSA) in children has recently gained momentum. Technical quality of HSAT is paramount to interpretability, with published data indicating wide variation in quality (46-87% 1,2). This audit aimed to assess the technical quality of HSATs performed at our Paediatric Trust. Standards HSAT was performed in line with published American Academy of Sleep Medicine (AASM) standards.3 Referral criteria specify non- syndromic children (2-17yrs) with clinical suspicion of OSA. In-laboratory quality standards were implemented to assess interpretability of each study. Minimum requirements were: total sleep time (TST) ≥ 4hrs, artefact-free SpO2 recording for ≥ 4hrs of TST, and signals required to score respiratory events (nasal flow and/or respiratory effort bands) for ≥ 4hrs of TST. Target interpretability score is ≥ 75%. Methods All consecutively recorded HSATs between 03/12/2019-01/03/2022 were retrospectively evaluated for meeting referral criteria and their interpretability. Results 97 HSATs were performed. Mean age 7.7 ± 4.3yrs (59% male). 80% of HSATs performed met referral criteria. Total interpretability was 76.3% with only a small difference identified between those performed on patients meeting referral criteria and those not (76.9% vs 73.7% respectively). Primary causes of uninterpretable studies were: intolerance of all sensors (26.1%), absence of SpO2 (26.1%), and insufficient signals required to score respiratory events (34.8%). Conclusion Interpretability score met our predefined target. Majority of HSATs were performed in patients meeting referral criteria. Recommendations to address uninterpretable HSATs include: improved parental teaching, modify SpO2 sensor attachment policy, and implement psychosocial support techniques. References G.G. et al. 2019. Journal of sleep research 2019;28(6):e12856. M.M. et al. Sleep Medicine 2020;68:146-152. R.B. et al. AASM 2020.