News Article

Silver Improves Efficiency Of Kesterite Solar Cells


Estonian researchers improve efficiency of solar cells from 6.6 percent to 8.7 percent

As a result of a two-year joint project, materials researchers at Tallinn University of Technology in Estonia have improved the efficiency of next generation solar cells by partial substitution of copper with silver in absorber material. They published the results in the Journal of Materials Chemistry A.

The TalTech researchers are developing cells using an unusual compound semiconductor material called kesterite, a non-toxic competitor to perovskite with the formula Cu2ZnSn(Se,S)4,

To produce kesterites, TalTech researchers use a monograin powder technology, which they say is unique. "The monograin powder technology we are developing differs from other similar solar cell manufacturing technologies used in the world in terms of its method. Compared to vacuum evaporation or sputtering technologies, which are widely used to produce thin-film structures, the monograin powder technology is less expensive," explains Marit Kauk-Kuusik (pictured above), senior researcher at TalTech Laboratory of Photovoltaic Materials.

Powder growth involves heating the chemical components in a chamber furnace at 750degC for four days. Afterwards, the mass obtained is washed and sieved. The synthesised microcrystalline powder, monograin powder, is then used for the production of solar cells. The powder technology differs from other production methods in particular due to its low cost, since it does not require any expensive high vacuum equipment.

The monograin powder consists of microcrystals that form parallel connected miniature solar cells in a large module (covered with an ultra-thin buffer layer). The researchers saysthis provides major advantages for photovoltaic modules: the photovoltaics cells are lightweight, flexible, can be transparent, while being environmentally friendly and significantly less expensive that silicon technology.

The indicator of the quality of photovoltaics is the efficiency. Efficiency depends not only on the properties of the materials used and the structure of the solar cell, but also on solar radiation intensity, angle of incidence and temperature.

The ideal conditions for achieving the maximum efficiency are in cold sunny mountains, not in a hot desert, as one would expect, because heat does not improve solar cell's efficiency. It is possible to calculate the maximum theoretical efficiency for each solar panel, which, unfortunately, has so far been impossible to achieve in reality, but it is an objective to pursue.

"We have reached the point in our development where partial replacement of copper with silver in kesterite absorber materials can increase efficiency by 2 percent. This is because copper is highly mobile in nature, causing unstable solar cell efficiency. The replacement of 1 percent copper with silver improved the efficiency of monograin layer solar cells from 6.6 percent to 8.7 percent," Kauk-Kuusik says.

The monograin layer solar cell technology is implemented by the Estonian-Austrian joint venture Crystalsol GmbH. In order to commercialise the photovoltaic technology developed, the researchers think the solar cell efficiency should be increased to 15 percent.

'The effect of Ag alloying of Cu2(Zn,Cd)SnS4 on the monograin powder properties and solar cell performance' by Kristi Timmo et al; Journal of Materials Chemistry A, Issue 42, 2019

AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.

We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.

Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.

So make sure you sign up today and discover the latest cutting edge developments across the compound semiconductor and integrated photonics value chain.



Search the news archive

To close this popup you can press escape or click the close icon.
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.

Please subscribe me to:


You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
Live Event