Solar inks are not new, but recent advances have made it possible to achieve more with printable solar cells. This article will focus on what has been achieved in the area of solar cells and the recent developments.
Solar Ink
Solar ink can be used to print solar cells on many different surfaces, including paper, plastic and fabric. Solar ink’s greater flexibility offers obvious advantages to consumers and builders.
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.
In Europe, recent advances have seen the development of solar cells which are both printable as well as 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.
Printing the cells onto plastic film would solve this particular problem. Researchers at the University of Swansea pioneered the use of a carbon-based ink with slot-die coating (a process 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 then extracts the charge.
Slot-die coating produces a final printed output consisting of flexible, rollable solar cells. It is therefore possible to print large areas of solar panels. But there is still much work to be done, for example, increasing the performance of the perovskite and enhancing its longevity by using protective coatings or lamination techniques.
Solar ink is an environmentally friendly product because it can easily be produced with low temperatures. This reduces energy consumption. The technique is also valuable because the demand for renewable solutions will continue to increase, which translates into more opportunities for the green economy and industry.
The latest 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. Overall, the trends are that volume continues to decrease while value of sold printing inks is continuing to increase. 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.
The sales of publication stains fell to just under 250,000 tonnes in 2022. The volume of packaging inks also fell, but this time only by 4% to 530,000 tons. In examining the specifics at the national level, we can see that:
• 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 has the highest value ink industry 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.