Alan D. F. Dunbar

Semiconductors underpin many modern technologies, from data processing and displays to power generation, and their performance relies on precise thin-film deposition processes. These processes control the composition and interfaces between device layers, ensuring that semiconducting materials function reliably without degradation. In high-value devices such as perovskite solar cells, variations in deposition methods can significantly affect both material use and product quality. Improving the precision, consistency, and sustainability of thin-film deposition is therefore essential to enable scalable, efficient, and environmentally responsible manufacturing. This study employs a process-based Life Cycle Assessment (LCA), extended to include activity-level steps, to evaluate environmental impacts across laboratory- and pilot-scale perovskite solar cell production. The analysis highlights energy consumption in processing equipment and facility operations as the dominant environmental burden, with the deposition stage representing a key target for efficiency improvements. Scaling from laboratory to pilot-scale production reduces perovskite solar cell manufacturing costs by approximately 99.8% per m² of active area, with an additional ∼8% reduction achieved through enhanced process control. At this scale, environmental impacts decrease by over 98% across global warming potential, human toxicity and aquatic ecotoxicity. Further integration of automated control systems lowers global warming and toxicity impacts by around 10%, while substituting grid electricity with low-carbon wind power amplifies these gains, reducing carbon emissions by up to 79%. The results demonstrate that combining process optimization with renewable energy sourcing provides a clear pathway toward sustainable, scalable perovskite solar cell manufacturing. The methodology is also broadly applicable to other thin-film semiconductor processes, offering guidance for improving operational efficiency while minimizing environmental impact.

Photovoltaics (PVs), the fastest-growing renewable energy source, play a crucial role in decarbonizing global energy systems.

Morin dye is known as a cheap and readily available selective ‘off → on’ fluorescent sensitiser when immobilised in a phase transfer membrane for the detection of Al³⁺ ions. Here, a morin derivative, NaMSA, which readily dissolves in water with good long-term stability is used in conjunction with a fibre-optic transducer with lock-in detection to detect Al³⁺ in drinking water below the potability limit. The combination of a water-soluble dye and the fibre-optic transducer require neither membrane preparation nor a fluorescence spectrometer yet still display a high figure of merit. The known ability to recover morin-based Al³⁺ cation sensors selectively by exposure to fluoride (F⁻) anions is further developed, enabling a complementary sensing of either fluoride anions, or aluminium cations, using the same dye with a sub-micromolar limit-of-detection for both ions. The sensor performance parameters compare favourably to prior reports on both aqueous aluminium and fluoride ion sensing.

Understanding the kinetics of the crystallization process for organometal halide perovskite formation is critical in determining the crystalline, nanoscale morphology and therefore the electronic properties of the films produced during thin film formation from solution. In this work, in situ grazing incidence small-angle X-ray scattering (GISAXS) and optical microscopy measurements are used to investigate the processes of nucleation and growth of pristine mixed halide perovskite (MAPbI_3–xCl_x) crystalline films deposited by bar coating at 60 °C, with and without additives in the solution. A small amount of 1,8-diiodooctane (DIO) and hydriodic acid (HI) added to MAPbI_3–xCl_x is shown to increase the numbers of nucleation centers promoting heterogeneous nucleation and accelerate and modify the size of nuclei during nucleation and growth. A generalized formation mechanism is derived from the overlapping parameters obtained from real-time GISAXS and optical microscopy, which revealed that during nucleation, perovskite precursors cluster before becoming the nuclei that function as elemental units for subsequent formation of perovskite crystals. Additive-free MAPbI_3–xCl_x follows reaction-controlled growth, in contrast with when DIO and HI are present, and it is highly possible that the growth then follows a hindered diffusion-controlled mechanism. These results provide important details of the crystallization mechanisms occurring and will help to develop greater control over perovskite films produced.

Polyelectrolyte adhesives, either poly[2-(dimethylamino)ethyl methacrylate] or poly(methacrylic acid), functionalized with a surface-active calix[4]resorcinarene were grafted onto silicon wafers. Adhesion studies on these grafted-to brushes using polyelectrolyte hydrogels of opposite charge showed that it is the calix[4]resorcinarene, rather than adsorption of polyelectrolyte monomers, that adheres the brush to the silicon substrate. The adhesion measured was similar to that measured using polymers grafted from the surface, and was stronger than a control layer of poly(vinyl acetate) under the same test conditions. The limiting factor was determined to be adhesive failure at the hydrogel-brush interface, rather than the brush-silicon interface. Therefore, the adhesion has not been adversely affected by changing from a grafted-from to a grafted-to brush, demonstrating the possibility of a one-pot approach to creating switchable adhesives.

The interchain spacing and screening length modification of deuterated PSS (d-PSS) backbone chains in zwitterion-doped PEDOT:d-PSS were studied as a function of the doping concentration using small angle neutron scattering. Results suggest that the dopant, 3-(N,N-Dimethylmyristylammonio)propanesulfonate (DYMAP), forms worm-like micelle structures in the PEDOT:d-PSS dispersion that grow in size as the doping concentration increases. The interchain spacing between negatively charged d-PSS remains unaffected by DYMAP up to 15 mM doping concentration. However, from 15 to 25 mM doping concentration, the interchain spacing increases due to steric interactions of grown DYMAP worm-like micelles with the d-PSS chains. At 30 mM doping concentration, the interchain distance between negatively charged d-PSS chains is reduced due to the gelation of the PEDOT:d-PSS dispersion caused by the crosslinking between long DYMAP worm-like micelles and d-PSS chains. Meanwhile, the screening length of the neutralized d-PSS segments attached to the PEDOT oligomers increases as the DYMAP concentration increases form 5 to 30 mM due to the neutralization of the negatively charged d-PSS segments by their Coulomb interaction with the cation in DYMAP.

In a proof‐of‐concept study, this work demonstrates that incorporating a specifically designed block copolymer as an interfacial layer between a charge transport layer and the photoactive layer in organic solar cells can enhance the interface between these layers leading to both performance and stability improvements of the device. This is achieved by incorporating a P3HT₅₀‐b‐PSS_x block copolymer as an interfacial layer between the hole transporting and photoactive layers, which results in the improvement of the interfacial roughness, energy level alignment, and stability between these layers. Specifically, the incorporation of a 10 nm P3HT₅₀‐b‐PSS₁₆ and a 13 nm P3HT₅₀‐b‐PSS₂₃ interfacial layer results in a 9% and a 12% increase in device efficiency respectively compared to the reference devices. In addition to having a higher initial efficiency, the devices with the block copolymer continue to have a higher normalized efficiency than the control devices after 2200 h of storage, demonstrating that the block copolymer not only improves device efficiency, but crucially, prevents degradation by stabilizing the interface between the hole transporting layer and the photoactive layer. This study proves that appropriately designed and optimized block copolymers can simultaneously stabilize and improve the efficiency of organic solar cells.

In situ wide-angle X-ray scattering (WAXS) has been measured during the spin coating process used to make the precursor films required for the formation of thin films of perovskite. A customized hollow axis spin coater was developed to permit the scattered X-rays to be collected in transmission geometry during the deposition process. Spin coating is the technique most commonly used in laboratories to make thin perovskite films. The dynamics of spin-casting MAPbI_3–xCl_x and FAPbI_3–xCl_x films have been investigated and compared to investigate the differences between the dynamics of MAPbI_3–xCl_x and FAPbI_3–xCl_x film formation. In particular, we focus on the crystallization dynamics of the precursor film formation. When casting MAPbI_3–xCl_x, we observed relatively fast 1D crystallization of the intermediate product MA₂PbI₃Cl. There was an absence of the desired perovskite phase formed directly; it only appeared after an annealing step that converted the MA₂PbI₃Cl to MAPbI₃. In contrast, slower crystallization via a 3D precursor was observed for FAPbI_3–xCl_x film formation compared to MAPbI_3–xCl_x. Another important finding was that some FAPbI_3–xCl_x perovskite was generated directly during spin-casting before annealing. These findings indicate that there are significant differences between the crystallization pathways for these two perovskite materials. These are likely to explain the differences in the lifetimes of the resulting perovskite solar cell devices produced using FA and MA cations.