Vol.:(0123456789) 1 3 Applied Nanoscience https://doi.org/10.1007/s13204-018-00949-4 ORIGINAL ARTICLE Utilization of 2D gahnite nanosheets as highly conductive, transparent and light trapping front contact for silicon solar cells Gobinath Velu Kaliyannan 1  · Senthil Velmurugan Palanisamy 1  · Manivasakan Palanisamy 2  · Moganapriya Chinnasamy 1  · Sankaranarayanan Somasundaram 1  · Nithyavathy Nagarajan 1  · Rajasekar Rathanasamy 1 Received: 10 November 2018 / Accepted: 31 December 2018 © King Abdulaziz City for Science and Technology 2019 Abstract The current scenario illustrates distinct interest in developing renewable energy sources for power generation. In this regard, several researches are performed in enhancing the power conversion efciency of solar cells. The present work focuses on utilizing ZnAl 2 O 4 (gahnite) spinel as antirefection coating material to improve the power conversion efciency of silicon solar cells. Gahnite was synthesized using two precursors namely zinc nitrate hexahydrate and aluminum nitrate nonahydrate through sol–gel technique. The thickness of the prepared gahnite sheets measured through atomic force microscopy was around 50 nm. Single to quintuple layers of gahnite was deposited on silicon solar substrate using spin coating technique. The infuence of gahnite coating on the structural, optical, electrical properties and cell temperature of silicon solar cells are analyzed. The synthesized gahnite bears spinel crystal structure in the form of two dimensional nanosheet. Increment in layer thickness proves the deposition of single to quintuple layer on silicon substrate. A maximum of 93% transmittance and 20.72% power conversion efciency at a low cell temperature (39.4 °C) has been achieved for triple layer deposition proving difusion of more photons on the substrate. The obtained results prove gahnite as suitable anti-refection coating material for enhancing the power conversion efciency of silicon solar cells. Keywords Silicon solar cell · Sol–gel · Anti-refection coating · Gahnite · Power conversion efciency Introduction The demand for energy is increasing day by day and devel- opment of sustainable power generation is a critical issue. To overcome this constraint, renewable energy sources such as solar energy are developed by researchers. In India, poly- crystalline silicon-based solar cells are vastly employed as energy conversion device owing to their technical charac- teristics and low cost. However, the power conversion ef- ciency (PCE) of polycrystalline solar cells is quite low due to high refection loss of sun illumination. Solar radiation is the most important factor in the design and the evaluation of photovoltaic devices. Solar radiation intensity alters for diferent geographical location. The latter plays a vital role in the surveys of sizing of photovoltaic device, hydrology, ecology, agronomy and evaluations of their performances (Tahâş et al. 2011). Several techniques were developed by researchers to improve the PCE of silicon solar cells through minimizing the refection losses. Anti-refection coating (ARC) is one among the efective approaches employed to control refection loss. ARC coating helps to reduce the optical losses and improve the absorption properties of the system (Bouhafs et al. 1998; Lien et al. 2006). In recent years, metal oxide semiconductors are widely employed as ARC material due to their potential optical and electrical properties. Zinc oxide based ARC thin flms deposited on silicon solar cells used as transparent conduc- tive thin flm electrodes possess considerable electrical con- ductivity, optical transparency, non-toxicity and good sta- bility to plasma environment with nominal production cost (Balaprakash et al. 2018; Verma et al. 2010). In addition, zinc oxide-based thin flm acts as a transparent conductive * Rajasekar Rathanasamy rajasekar.cr@gmail.com 1 School of Building and Mechanical Sciences, Kongu Engineering College, Perundurai, Tamil Nadu 638 060, India 2 Department of Chemistry, Bharathiar University Arts and Science College, Modakurichi, Erode, Tamil Nadu 638104, India