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Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic greenhouse gas emissions, and meeting increases in future demand for low-carbon electricity. In order to fulfill ambitions for net-zero carbon dioxide equivalent (CO 2 eq) emissions worldwide, the global cumulative capacity of solar PVs must increase by an order of magnitude from 0.9 TW p in 2021 to 8.5 TW p by 2050 according to the International Renewable Energy Agency, which is considered to be a highly conservative estimate. In 2020, the Henry Royce Institute brought together the UK PV community to discuss the critical technological and infrastructure challenges that need to be overcome to address the vast challenges in accelerating PV deployment. Herein, we examine the key developments in the global community, especially the progress made in the field since this earlier roadmap, bringing together experts primarily from the UK across the breadth of the PVs community. The focus is both on the challenges in improving the efficiency, stability and levelized cost of electricity of current technologies for utility-scale PVs, as well as the fundamental questions in novel technologies that can have a significant impact on emerging markets, such as indoor PVs, space PVs, and agrivoltaics. We discuss challenges in advanced metrology and computational tools, as well as the growing synergies between PVs and solar fuels, and offer a perspective on the environmental sustainability of the PV industry. Through this roadmap, we emphasize promising pathways forward in both the short- and long-term, and for communities working on technologies across a range of maturity levels to learn from each other.

Halide perovskites offer outstanding potential for the next generation of cost-effective optoelectronic devices. Perovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) of 26.7% in single-junction configurations and 34.6% in perovskite/silicon tandem cells. However, before perovskites can be commercially viable on a large scale, challenges related to device performance and phase stability must be addressed. Despite their impressive performance, perovskites still exhibit a high density of defects and non-radiative trap states, leading to local electrical and chemical heterogeneities that limit overall device efficiency. Gaining a deep understanding of these nanoscale heterogeneities is crucial for minimizing performance losses and improving stability. Scanning probe microscopy (SPM) is a key technique for exploring material properties at the nanoscale with high precision. This thesis focuses on using SPM to characterize perovskites and understand their nanoscale charge transport properties. The first section of this thesis examines the thermal reaction between copper (Cu) and perovskite absorbers, which is particularly relevant as copper is a common electrode material in inverted p-i-n perovskite structures. It has been frequently reported that metal electrodes can diffuse into the perovskite layer. The findings reveal that Cu particles migrate to grain boundaries (GBs) and react with lead iodide (PbI2) during the perovskite's decomposition, with Cu ions primarily integrating into the A-site cations of the perovskite lattice. This leads to the formation of Cu-rich, organic A-site-deficient perovskites mainly at the GBs, which detrimentally affect the overall performance of the device. The second section of the thesis explores the impact of adding methylammonium chloride (MACl) to formamidinium lead triiodide (FAPbI3) perovskites, a universal additive for achieving high-efficiency perovskites. Using nano-IR AFM measurements, the incorporation of MACl causes heterogeneity in formamidinium (FA+) cations within FAPbI3 perovskites was revealed, promoting the selective formation of benign methylformamidinium (MFA+) byproducts primarily at GBs. These byproducts suppress the unwanted local formation of 2H-FAPbI3 and enhance charge separation at the GBs. The final section of this thesis demonstrates that introducing ferroelectric polarization using a highly crystalline 2D PEA2PbI4 perovskite fabricated through the solid-state in-plane growth (SIG) process on top of a 3D perovskite layer can significantly improve charge separation, thereby boosting the performance of perovskite solar cells. This results in the formation of distinct polarization between GBs and grain interiors (GIs) regions. This polarization facilitates effective charge separation due to the presence of opposite dipoles, leading to an exceptional PCE of 25.8%, with a certified efficiency of 25.2%.

Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic greenhouse gas emissions, and meeting increases in future demand for low-carbon electricity. In order to fulfil ambitions for net-zero carbon dioxide equivalent (CO2eq) emissions worldwide, the global cumulative capacity of solar PVs must increase by an order of magnitude from 0.9 TWp in 2021 to 8.5 TWp by 2050 according to the International Renewable Energy Agency, which is considered to be a highly conservative estimate. In 2020, the Henry Royce Institute brought together the UK PV community to discuss the critical technological and infrastructure challenges that need to be overcome to address the vast challenges in accelerating PV deployment. Herein, we examine the key developments in the global community, especially the progress made in the field since this earlier roadmap, bringing together experts primarily from the UK across the breadth of the photovoltaics community. The focus is both on the challenges in improving the efficiency, stability and levelized cost of electricity of current technologies for utility-scale PVs, as well as the fundamental questions in novel technologies that can have a significant impact on emerging markets, such as indoor PVs, space PVs, and agrivoltaics. We discuss challenges in advanced metrology and computational tools, as well as the growing synergies between PVs and solar fuels, and offer a perspective on the environmental sustainability of the PV industry. Through this roadmap, we emphasize promising pathways forward in both the short- and long-term, and for communities working on technologies across a range of maturity levels to learn from each other.

This study evaluated milking characteristics and milk productivity of a domestically developed automatic milking system (AMS-K) and compared its performance with a commercially imported AMS (AMS-C), under identical farm management conditions. Milking performance of AMS-K was monitored over a three-month operating period, and a comparative analysis was subsequently conducted using a total of 50 Holstein cows, with 25 cows allocated to each system based on similar parity, days in milk, and milk yield. During the three-month operation of AMS-K, milk yield per milking significantly increased in from 13.81 kg in the 1st month to 15.99 kg in the 3rd month, and daily milk yield increased by 4.01–7.52% compared with the initial operating period. Milking frequency decreased from 2.53 to 2.27 times per day, but remained higher than conventional twice-daily milking. Average milking interval increased from 9.37 to 10.34 h, which was within the optimal range (9–10 h) for AMS operation. Milking stall occupancy and teat-cup attachment times gradually increased, whereas milking time showed no significant change. Somatic cell count initially increased but stabilized after three months. Milking efficiency ranged from 2.44 to 2.56 kg/min. In the system comparison, AMS-C showed shorter milking stall occupancy time, higher milking frequency, and higher milking efficiency than AMS-K, whereas AMS-K showed higher milk yield per milking, associated with longer milking interval. Across both systems, multiparous cows exhibited longer milking intervals and higher milk yields than primiparous cows in both AMSs. Theoretical milking capacity per AMS was 54.45 cows (primiparous) and 37.77 cows (multiparous) for AMS-K, sufficient for an average Korean dairy farm. Our results demonstrate that AMS-K achieved stable milking performance, milk quality, and operational efficiency comparable to the imported AMS. AMS-K shows great potential for practical applications and commercialization in Korean dairy farms.

Virtual reality (VR) has been utilized in clinical treatment because it can efficiently simulate situations that are difficult to control in the real world. In this study, we evaluated the efficacy of VR in patients with chronic subjective tinnitus. We assessed the clinical effectiveness based on electroencephalogram (EEG) analysis and questionnaire responses after patients participated in a 6–8-week VR-based tinnitus relief program. The intervention involved removing tinnitus avatars in the VR, through which we expected the patients to experience subjective tinnitus control. Standardized low-resolution brain electromagnetic tomography was used to analyze changes in source activity in prefrontal regions associated with tinnitus. The study included patients aged 27–68 years with chronic non-pulsatile tinnitus lasting ≥3 months. Patients completed VR sessions, neurological EEGs, and questionnaires. Statistically significant differences were observed in the tinnitus handicap questionnaire total scores immediately after treatment (p = 0.002) and 1-month post-treatment (p = 0.001) compared to those before treatment. Significant changes were also found in the visual numeric scale and profile of mood states scores 1-month post-treatment. Additionally, significant changes were observed in sensor-level and source-level power spectrum criteria immediately following the VR experiment, suggesting that similar to some forms of cognitive behavioral therapy, VR-based programs may help alleviate tinnitus-related distress in patients with chronic subjective tinnitus.