Murthy Grandhi

Powering your electronic devices with indoor lighting might soon be reality

Picture this: you turn on your coffee machine as your kids are watching TV on a gloomy Saturday morning in November. Your coffee machine is powered by your kitchen lights, your kitchen lights are powered by the light of Peppa the Pig blasting on the TV screen. No electric wires, plugs or electricity bills required. This is theoretically possible with indoor photovoltaics that Murthy Grandhi is currently conducting research on at Tampere University.

Murthy Grandhi, a Postdoctoral Research Fellow at the Tampere Institute for Advanced Studies and a postdoctoral researcher in the Hybrid Solar Cells (HSC) group at Tampere University moved to Tampere in 2020 to pursue his long-standing aim of conducting research on photovoltaic applications, which means applications that convert light into electricity.

– Imagine how exciting it will be to capture the light coming from indoor lights in homes, supermarkets, and other indoor environments and convert it into electricity to power various electronic devices. It is possible with indoor photovoltaics, Grandhi explains.

Photovoltaics is the conversion of light, traditionally sunlight, into electrical power. The photovoltaic effect is a physical and chemical phenomenon, widely studied and commercially used in solar panels.


A well-known material called halide perovskite recently changed the game for solar electricity

Just ten years ago no-one thought that perovskite, a calcium titanium oxide mineral first discovered in 1839, would revolutionize research in photovoltaics. Currently perovskite is seen as a promising new raw material for solar panels.

– Getting rid of lead, a toxic metal in perovskite, is mandatory for its widespread applications. The resultant materials are perovskite-inspired materials, Grandhi says.

– The photovoltaic devices based on these perovskite-inspired materials possess suitable properties for indoor light harvesting.

The studies on this research topic are still in their infancy due to challenges associated with efficient indoor light-to-electricity conversion. Indoor light, which mainly comes from (fluorescent lamps (FL) and light-emitting diodes (LED), is very different from sunlight in terms of the emission spectra and intensity. This is also why the same technology that harvests sunlight in solar panels cannot be used to harvest the light from indoor lighting.

– My current research aims to establish a processing method for new perovskite-inspired materials that optimizes various photovoltaic device aspects for efficient indoor light harvesting, Grandhi explains.


The future shines brightly for solar energy and indoor photovoltaics

Amidst the current global energy crisis, solar energy is the only key to a clean energy future. Grandhi’s future plans involve developing low-cost inorganic semiconductor thin films and nanocrystals for efficient and eco-friendly indoor photovoltaics and solar cells.

– My future research may certainly lead to a high-impact contribution to the scientific as well as the industrial community, Grandhi concludes.

Keywords: solar energy, solar cells, photovoltaics, indoor photovoltaics, clean energy, perovskite, Tampere University, Tampere Institute for Advanced Study