Solar inks have not been around for very long, but recent advancements in the field of printable solar cells has made them more effective. This article focuses on the latest developments in this field and what is possible.
Solar ink, a form conductive ink, is capable of printing solar cells on a variety of substrates including plastics and fabrics. Solar ink printing offers greater versatility, which is beneficial to both consumers and contractors. This flexibility could include broad-wall solar power generation for the home.
It is possible to create thin, flexible solar panels. This technology overcomes the limitations associated with fixed solar cells, which, despite their eco-friendliness, are difficult to manufacture and fragile.
The industry is also in the position that, to meet the demands of the 21st century for traditional solar cells, the materials required for their production will be exhausted by mid-century.
Recent developments in Europe have led to the emergence and use of solar cell that is both printable and rollable. They have been produced in labs under conditions that remove oxygen and water, resulting in cells with an efficiency comparable to conventional solar cells.
This would be very expensive to manufacture in the industry, but printing them on plastic film solves this problem. Researchers at the University of Swansea pioneered the use of a carbon-based ink with a slot-die coating technique (a technique that is used to produce photographic films) for on-film printing of solar cells.
One of the requirements for this been the development of perovskite and semiconductor layers that have thicknesses of 50 – 500 nm within the cell. Years of research has also led to a process which eliminates the need for highly toxic solvents in solar cell production.
Solar cells generate free electrons when light strikes them. The semiconductor layer is crucial in achieving an efficient power conversion. It prevents electron absorption. Carbon ink is used to extract the charge.
The slot-die process produces flexible solar cells that can be rolled up. It is therefore possible to print large areas of solar panels. There is still much to be done in this area, including increasing the efficiency of perovskite structure and finding ways to enhance their longevity through lamination or protective layering techniques.
The production of solar ink in general has already proven to be an eco-friendly option, as it can be produced at low temperatures and therefore reduce energy consumption. The technique is also valuable because the demand for renewable solutions will continue to increase, which will translate into more opportunities for the green economy and for industry.
Recent Statistics on European Sales
The European Printing Ink Association, or EuPIA, has recently published their annual statistics for the printing ink industry on the continent. The overall trends show that the volume of inks continues to decline while their value is increasing. Statistics are based on the 26 member companies, which account for 90% of total sales.
Publication inks include web offset (coldset or heatset), sheetfed offset, publication gravure and overprint varnishes. Packaging inks are flexographic inks. Specialty gravure inks. Radcure inks.
In 2022, sales of publication inks fell by a little over 15% to 250,000 tonnes. Packaging inks were also sold at lower volumes, by 4% and 530,000 tonnes. When we look at the national details, some important points and indicators emerge:
• Of the big five economies in the west, Italy boasted the strongest annual growth in ink sales at 13.6%, increasing the value of inks to its economy to more than €400 million. Spain placed second with ink sales rising by 10.7% in 2022 to total more than €200 million. The UK and France increased sales by 8.5% and 6.9% respectively to both reach about €260 million. Germany remains the pre-eminent industry and market with sales in excess of €575 million and growing by 7.4%. Italy is the second most valuable market for ink after Germany.
• From the mid-sized and smaller economies, some of the best performers were the Netherlands, Czech Republic, Sweden, Croatia and Portugal, although none of these have ink sales in excess of €100 million and most have sales fewer than €50 million.
• In Eastern Europe disruption for some brought opportunity for others. Ukrainian ink sales fell by nearly 44% to around €13-14 million while those in neighbouring Belarus rose by 115% to about €12 million. Russian ink sales were seen to fare badly last year, collapsing by 35% to around €110 million. Meanwhile in the regionally prominent Turkish economy, turnover from inks grew by more than 24% to over €275 million. Inks are now the third most valuable sector in Europe, after Germany and Italy.