This article develops a publication-ready integrative research study based strictly on the supplied references and examines the evolving technological, theoretical, numerical, and techno-economic landscape of next-generation solar cells, with particular emphasis on perovskite photovoltaics, tandem solar architectures, GeSe thin-film devices, CIGS-associated heterostructures, and the continuing benchmark role of crystalline silicon. The reviewed literature indicates that the contemporary photovoltaic field is no longer defined only by incremental material improvements within isolated single-junction platforms. Instead, it is increasingly shaped by the interaction between theoretical efficiency limits, absorber-layer engineering, interface control, defect management, tandem integration, stability enhancement, and cost-performance trade-offs (Al-Harbi & Kais, 2015; Andreani et al., 2019; Hadi et al., 2016; Zhang et al., 2023). Perovskite solar cells occupy a central place within this transition because they combine exceptional optoelectronic tunability with compatibility for tandem configurations and numerical design optimization, yet they remain constrained by long-term operational stability and commercialization uncertainty (Guo & Min, 2017; Zhao, 2022; Baumann et al., 2024; Zhu et al., 2023). In parallel, GeSe and CIGS-related thin-film systems continue to provide valuable pathways for absorber diversification, defect-tolerant performance, and tandem integration possibilities (Xue et al., 2017; Liu et al., 2017; Liu et al., 2020; Al-Hattab et al., 2021).

Using a qualitative integrative methodology, this study synthesizes foundational theory, simulation-based device research, materials-oriented investigations, and cost-oriented analyses. Four major findings emerge. First, the literature consistently shows that efficiency improvement is increasingly being pursued through tandem and multi-junction strategies rather than through single-junction refinement alone (Hadi et al., 2016; Liu, Junbo, & Xudong, 2023; Singh et al., 2023). Second, SCAPS-based numerical simulation has become a critical tool for absorber, transport-layer, defect, and interface optimization across multiple material systems (Atourki et al., 2016; Sharma et al., 2023; Ompong & Clements, 2024). Third, stability has emerged as the decisive bottleneck separating laboratory excellence from real-world deployment in perovskite-containing devices (Baumann et al., 2024; Zhu et al., 2023). Fourth, cost competitiveness remains unresolved: perovskites may outperform crystalline silicon in some future scenarios, but only if manufacturability, durability, and module-level reliability converge with their strong device-level performance potential (Woodhouse et al., 2019; Liu et al., 2025). The article concludes that the future of solar cell research will depend on integrating theoretical limits, practical material engineering, reliable device architectures, and lifecycle-aware economic analysis into a unified photovoltaic design paradigm.