During scheduled maintenance on a hot water storage facility in Marburg, Germany, in November 2021, engineers from the municipal utility attached 18 solar panels to the exterior of the main cylindrical tank.

These solar panels, developed by the German solar company Heliatek, differ from the usual flat, rigid, silicon panels commonly seen on rooftops or in solar parks. Instead, they are ultra-thin organic films.

Heliatek’s revolutionary solar panels

Heliatek has extensively used these flexible panels on structures like office towers, curved bus stop roofs, and even the cylindrical shaft of a windmill that stands 80 meters tall.

The company’s objective is to expand the applications of solar power beyond flat land. There’s a significant market where traditional photovoltaics are not effective, according to Jan Birnstock, the Chief Technical Officer at Heliatek.

Compared to silicon panels, the organic photovoltaics (OPVs) used by Heliatek are more than 10 times lighter and, in some cases, can be produced at half the cost. Some OPVs are even transparent, making it possible for solar panels to be incorporated into building facades, windows, and indoor spaces.

Birnstock imagines a future where every building is transformed into an electricity-generating structure.

According to Science, Heliatek’s panels are among the few OPVs currently in practical use. They convert around 9% of sunlight into electricity, which is much less than inorganic thin film alternatives.

However, researchers worldwide have made significant strides in developing new materials and designs. In laboratory prototypes, these advancements have achieved efficiencies of nearly 20%. This approaches the efficiency levels of silicon and alternative thin-film solar cells made from materials like copper, indium, gallium, and selenium (CIGS).

Unlike silicon crystals and CIGS, which have limited chemical options available to researchers, OPVs offer the flexibility to modify bonds, rearrange atoms, and incorporate elements from across the periodic table. These adjustments provide chemists with the ability to optimize their materials’ light absorption, charge conduction, and resistance to degradation.

While OPVs still have some shortcomings in these aspects, there is substantial room for exploration and improvement, as stated by Stephen Forrest, an OPV chemist at the University of Michigan, Ann Arbor.

Scaling laboratory-made OPVs to produce large-scale panels is still a difficult task, despite their promising attributes. However, the potential of OPVs is substantial.

OPVs and climate change

Conventional solar power, primarily based on silicon, has already achieved significant success as a green energy source. Conventional solar panels provide about 3% of global electricity.

Solar energy is the fastest-growing energy source, with an annual increase of over 200 gigawatts. There’s currently enough solar energy to power 150 million homes worldwide. With sustained engineering advancements and a global supply chain, the price of solar power continues to decrease.

However, the growth of solar and other green energy sources is insufficient to meet the increasing demand and address the need to mitigate climate change. The world’s electricity demand is projected to double by 2050 due to global economic development, population growth, and the expected shift of vehicles from petroleum to electricity.

To achieve global net zero carbon emissions by 2050, countries must install renewables at a pace four times faster than the current rate, as stated by the International Energy Agency. This represents a formidable challenge. The world requires rapid deployment of new renewable energy sources.

Advocates of OPVs, including Heliatek, do not see this technology as a replacement for conventional silicon panels. Instead, they view it as an enabler for new and innovative uses of solar power where silicon panels are not feasible.

For more information about Heliatek’s ultrathin organic solar panels, check out this insightful video.

Image Source: DW, https://shorturl.at/bEV19