Despite persistent innovations in all areas of PV production, which have helped to push prices for solar generated electricity down to previously unthinkable levels, the upfront investment required for solar remains high, prohibitively so for the 1.2 billion people living without reliable access to electricity.
It is in these energy poor communities that easily deployable solar could have a transformative effect. In most cases, companies have taken a business model approach to serving these communities – either through pay-as-you-go schemes for small rooftop installations, or building larger installations and leveraging anchor tenants such as phone companies to reduce risk.
The research team from several universities, led by Penn State professor Akhlesh Lakhtakia has taken a different approach, developing a straight forward solar cell that, while less efficient than most on the market, can produce a viable level of electricity at a greatly reduced production cost.
“Because poor people can’t afford their energy resources, they lack the wherewithal to improve their economic status,” says Lakhtakia. “They don’t need the most efficient sources. They need affordable ones, and a helpful nudge to improve their lives, that motivated us in our research.”
Lakhtakia and the team worked with Schottky-barrier solar cells, using indium gallium nitride alloy as a semiconductor. “Instead of using silicon with the Schottky cell, we explored materials that could give us some advantage with their semiconducting properties,” says Lakhtakia. “We chose indium gallium nitride, an alloy in which the proportions of indium and gallium can be varied.”
By tailoring this proportion, and incorporating a metallic back reflector, the team says it has been able to increase photon absorption and generate more current, ultimately increasing efficiency from 13% to 17%.
The researchers estimate that the simplicity of the concept, as well as the reduction in materials required could greatly reduce manufacturing costs, making PV technology affordable for more communities across the globe.
“Sometimes you have to solve societal problems not in the most efficient way, but in the most economical way,” continues Lakhtakia. “These solar cells could be deployed widely in energy resource-poor areas, and provide enough electricity to help individuals and families meet their most basic human needs.”