Qazi Riti Mahpara Progoti, H.M. Wasi Uddin, Shifat E. Arman, Sadit Bihongo Malitha
The rapid growth of global energy demand and the environmental impacts associated with fossil-fuel-based energy systems have intensified the need for sustainable and multifunctional renewable-energy technologies. Transparent and semi-transparent photovoltaic (TPV/STPV) systems have emerged as promising candidates because they combine electricity generation with the optical functionality of conventional transparent materials. This review critically examines recent advances in transparent solar technologies, including polymer solar cells, luminescent solar concentrators, near-infrared transparent organic photovoltaics, thin-film photovoltaics, and quantum-dot-based transparent photovoltaics. Recent studies demonstrate that semi-transparent photovoltaic devices can achieve power conversion efficiencies (PCEs) exceeding 14–16% at average visible transmittance (AVT) values of approximately 25–35%, while highly transparent systems with AVT values above 50–70% generally achieve PCEs of 6–10%. The review comparatively analyzes device architectures, optical-management strategies, transparent electrodes, and the intrinsic transparency–efficiency trade-off governing device performance. Furthermore, multifunctional applications in building-integrated photovoltaics, consumer electronics, vehicle-integrated photovoltaics, agrivoltaics, and greenhouse systems are critically evaluated using recent quantitative metrics including energy savings, indoor-light harvesting, land-use efficiency, and thermal management. Key commercialization barriers, including long-term operational stability, lead toxicity in perovskite systems, large-area fabrication challenges, transparent electrode cost, and scalable manufacturing limitations, are also discussed. Finally, future research directions involving tandem architectures, spectral-selective engineering, and flexible transparent electrodes are highlighted to support the transition of transparent photovoltaic technologies from laboratory-scale demonstrations to practical large-scale deployment.