TAGRA 2025

Perovskite solar cells (PSCs) are a leading candidate for next-generation photovoltaic technology, offering high-power conversion efficiency (PCE) and cost-effective fabrication. While is conventionally used as the electron transport layer (ETL), its required high-temperature crystallization (450) severely limits its integration into flexible devices built on heat-sensitive substrates. The growing demand for flexible and wearable energy harvesters necessitates the development of alternative low-temperature ETL materials. Zinc oxide nanorods (ZnO NRs) are a promising substitute due to their low-cost, low-temperature synthesis, high electron mobility, and aligned nanostructure. However, pristine ZnO often suffers from intrinsic defect states that hinder charge extraction and reduce PCE. To address this, we investigated nickel (Ni) doping as a strategy to modify the electrical and structural properties of ZnO. In this study, Ni-doped ZnO NRs were synthesized via a low-temperature hydrothermal growth method with varying Ni concentrations (0, 1, 3, and 5 mol%) and growth durations (5 and 9 hours) at 100C. Their structural, morphological, and optical properties were thoroughly analyzed using XRD, EDX, FESEM, and UV–Vis spectroscopy. Photovoltaic performance was assessed via current–voltage (I–V) characterization. The results demonstrate that controlled Ni incorporation successfully improved crystallinity, suppressed defect density, and significantly enhanced electron transport. This led to a marked increase in PCE compared to devices utilizing undoped ZnO. This research establishes Ni-doped ZnO NRs as a promising, low-temperature, and cost-effective ETL material for high-efficiency flexible PSCs. These findings offer valuable insights for developing scalable and energy-efficient photovoltaic devices critical for advancing flexible electronics and sustainable energy applications.