The paper begins by highlighting the escalating global energy demand driven by industrial growth and population increase. It emphasizes the need to transition from fossil fuels to renewable energy sources like solar PV to meet this demand and mitigate environmental damage. The introduction defines solar energy and solar irradiance, explaining the process of converting solar irradiance into thermal or electrical energy. It then contrasts solar energy's sustainability with that of fossil fuels, noting the abundance of solar energy yet highlighting the cost challenges associated with its collection, conversion, and storage. The introduction also compares solar energy to other renewable sources (Biomass, Geothermal, Hydro-energy, Wind energy) highlighting its advantages and disadvantages, before stating the paper's aim which is to explore the diverse applications of solar PV systems and their contribution to achieving the Sustainable Development Goals (SDGs) through a bibliometric study analyzing publication trends related to solar energy and its applications (Large Scale Solar PV, Residential Solar PV, Green Hydrogen, Water Desalination, and Transportation) within the framework of the SDGs, identifying research gaps, and determining frequent keywords in each field.

The paper reviews the fundamentals of solar PV technology, explaining the photovoltaic (PV) effect and the components of a solar PV system (PV panel/array, battery, charge controller, inverter). It categorizes solar PV technologies into three generations: first-generation (monocrystalline and polycrystalline silicon cells), second-generation (thin-film cells like amorphous silicon, cadmium telluride, and copper indium gallium diselenide), and third-generation (under research and development, including organic PV and concentrated PV cells). A comparison table summarizes the advantages and disadvantages of each generation. The literature review then delves into the applications of solar PV technology, starting with large-scale solar PV power plants. It discusses their components (PV modules, mounting and tracking systems, inverters, transformers, and grid interface) and the factors influencing their design and performance. Residential applications of solar PV are explored, comparing grid-connected and stand-alone systems. The review then explores the use of solar PV in powering HVAC units, water pumps, and its crucial role in green hydrogen production, where it contrasts grey, blue, and green hydrogen production methods. Further applications in water desalination (reverse osmosis, electrodialysis reversal, and membrane distillation) and transportation (electric vehicles) are reviewed, highlighting the potential of solar energy in mitigating CO2 emissions and promoting sustainable transportation.

The bibliometric analysis utilized the Scopus database to collect data on scientific publications related to "solar" and its applications in the context of the SDGs from 2011 to 2021. The initial search yielded 276,989 documents, which were further refined by language (English) and document type (journal publications). This was followed by a combined search with each SDG individually along with the five chosen solar applications. Data cleaning in Microsoft Excel involved removing duplicates and repeated words to prepare the dataset for analysis. The process involved formulating a search query, specifying the date range (2011–2021), applying restrictions to the search (English language, journal publications), collecting the publications, performing data extraction from Scopus, data cleaning, creating dashboards, carrying out bibliometric analysis, and creating visual representations in PowerPoint and word art. The research focuses on identifying the distribution of solar-related publications across various SDGs and the five applications, analyzing publication trends over time, and identifying frequent keywords within each SDG and application.

The analysis of 126,513 documents revealed that SDG 7 (Affordable and Clean Energy) dominated solar energy research, accounting for over 72% of the publications. A significant research gap was identified across several other SDGs, especially SDGs 1, 4, 5, 9, 10, and 16. The number of publications increased annually, indicating growing interest in solar energy's role in sustainable development. Among the five applications, large-scale solar PV power plants had the highest number of publications, followed by transportation, residential applications, water desalination, and green hydrogen production. The analysis of keywords revealed "Solar Power Generation" as the most frequent keyword in the overall solar analysis, while other applications featured keywords directly related to their respective fields (e.g., "Photovoltaic Cells" for residential and large-scale applications, "Hydrogen Production" for green hydrogen). Country-wise analysis showed China, the USA, and India as major contributors to solar energy research, with China consistently leading in several categories. Dashboards summarizing key findings are created based on total publications, patents, open-access articles, yearly publications, and top three countries. These dashboards visually represent the most significant findings, including the total number of publications, number of patents registered, percentage of open-access articles, yearly publication trends, top three countries by publication count, and a word cloud depicting the most frequent keywords extracted from the data. Significant differences are observed between the leading countries (China, USA) and the others, suggesting potential future trends.

The findings highlight the disproportionate focus on the technical aspects of solar energy within SDG 7, neglecting the broader social and economic dimensions of its impact on other SDGs. The significant research gap in areas like poverty reduction, quality education, gender equality, and peace necessitates a shift in research priorities to address these interconnected aspects of sustainable development. The geographical distribution of research, with China, the USA, and India as dominant contributors, indicates a need for wider global participation to ensure equitable access to solar energy technologies and their benefits. The growing number of publications signifies the increasing recognition of solar energy's importance, yet emphasizes the need to direct this growth toward more holistic sustainability goals. The keyword analysis confirms the focus on specific technological aspects within each application, suggesting the need for interdisciplinary research that integrates technological advancements with societal needs and economic considerations.

The study concludes that while solar energy holds immense potential for sustainable development, research efforts must broaden beyond the technical aspects of clean energy production to encompass the social, economic, and political dimensions that impact other SDGs. The disproportionate research focus on SDG 7 necessitates a strategic redirection of research funding and collaboration to address the identified research gaps. Future research should investigate the societal and economic impacts of solar energy, focusing on job creation, GDP growth, and gender equality within solar projects. Policymakers should align funding with national SDG priorities, promote broader global participation, and encourage open-access publication to enhance knowledge dissemination.

The study is limited by its reliance on the Scopus database, potentially excluding publications from other sources. The keyword analysis, while insightful, might not fully capture the nuanced relationships between solar energy applications and different SDGs. The bibliometric analysis provides a quantitative overview of research trends but doesn't delve into the quality or impact of individual studies. The analysis is limited to the period 2011-2021, therefore missing more recent data that could change the conclusions.