Magnetic nanoparticles help make smarter solar cells
doi:10.1038/nindia.2019.79 Published online 19 June 2019
Researchers have synthesised high-performance solar cells based on magnetic nanoparticles that can harness solar energy and convert it into electricity more efficiently than existing solar cells1.
Since the process to make these solar cells is eco-friendly and of low cost, they can be used widely to make electricity.
Recent studies have shown that an externally applied magnetic field can accelerate the transport of charge carriers in solar cells. However, it is not always possible to incorporate an electromagnet into a solar cell device.
To find a way, scientists from the Indian Institute of Technology and the CSIR-Indian Institute of Chemical Technology in Hyderabad, India, first deposited a mixture of titanium dioxide paste and ferric oxide nanoparticles on fluorine-doped glass slides coated with tin oxide. They then prepared the solar cells by dipping the coated glass slides in a solution of a specific light-sensitive dye.
When exposed to sunlight, the solar cells were found to reduce light loss due to reflection. This, in turn, increased their efficiency in absorbing light. Sunlight also easily penetrated through the glass slides towards the active layer of the cells.
The presence of magnetic nanoparticles in the active layer contributed significantly to the power conversion efficiency of the devices. The nanoparticles generated an internal magnetic field that increased the numbers of dissociated charge carriers in the devices, increasing open circuit voltage.
The dye molecule in the solar cells also played a vital role in enhancing the current, explain the researchers. The dye absorbs the light energy and causes electrons in the dye to jump to a layer containing titanium dioxide paste and then to the external circuit, causing a flow of electrons and leading to a current.
1. Kannan, U. M. et al. Demagnetization field driven charge transport in a TiO2 based dye sensitized solar cell. Sol. Energ. 187, 281-289 (2019)