New Solar Cell Doubles As a Touch Screen

A new finding from Singapore's Nanyang Technological University (NTU) demonstrates yet again how the flexibility and wide-ranging applicability of solar power provides it with advantages that are impossible to achieve with fossil forms of energy. NTU's breakthrough is a new solar cell material that could also be used to make the now-ubiquitous touch screens for electronic devices, information kiosks and many other display forms.

The integrated solar cell/touch screen concept parallels the emergence of building-integrated solar cells, as well as solar cells that can be incorporated into fabrics and other wearable or portable items.

In addition to the potential energy cost savings related to consumer products, NTU's new solar cell material could also provide businesses with a low-emission platform for colorful lighting displays, especially when combined with a storage system that enables night-time use.

A new solar cell material from NTU

The main challenge for solar cell innovators is balancing the cost of the cell against the solar conversion efficiency of the cell.

Currently, silicon is the gold standard for efficiency, but when you consider other factors, such as the cost of raw materials, manufacturing, shipping and installation, as well as the range of applications, silicon is making room for a new generation of solar cells.

NTU's solution is perovskite, a relatively inexpensive mineral composed of calcium titanate (titanate is a salt composed of titanium and oxygen), originally discovered in Russia.

Initially, the NTU team was focused on developing a new hybrid solar cell material made with perovskite. The touch screen angle came almost by accident, when the lead researcher had his team shine a laser on the hybrid material.

In a highly unusual result for a solar cell, the material glowed brightly. The phenomenon demonstrated that the perskovite hybrid was a good light emitter as well as a good solar energy absorber.

So far, the team has identified at least four factors in favor of the new material. One is its durability as a solar energy collector, and the another is its "tunability." That refers to the wide range of colors that the team can achieve by tweaking the composition of the hybrid.

A third factor is the hybrid's translucency, which could result in a new breakthrough for building-integrated solar, since it could be used in place of tinted windows.

Finally, the material can also emit light in laser form, which provides it with a whole new range of applications as the basis for light detection and control devices.

Perovskite and Russia

It's worth noting, in consideration of the inflammatory situation currently underway between Russia and Ukraine, that sourcing of raw materials presents a critical challenge for the solar industry specifically and the clean technology sector in general.

Much of today's clean tech depends on silicon, lithium and other materials that are vulnerable to commodities price spikes, with non-source countries being particularly vulnerable.

In this regard the U.S. is at a disadvantage, so the race is on to develop domestic sources. Lithium production in the U.S., for example, is on the rise -- thanks partly to federal funding for expansion of the Kings Mountain lithium plant by the company Rockwood Lithium.

Federal funding is also behind efforts to develop domestically-sourced alternative materials, through the REACT (Rare Earth Alternatives in Critical Technologies), initiative under the Department of Energy.

Last year, the administration also launched the Critical Materials Institute, an innovation hub organized under the Energy Department.

As for perovskite, the U.S. could be in a good position to develop a clean tech sector based on that material, since Arkansas is one known domestic source.

Image (cropped): Courtesy of NTU

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