Perovskite-silicon solar cells break the 30% efficiency barrier

Published
December 8th, 2022

A collaborative effort led by EPFL’s Photovoltaics and Thin Film Electronics Laboratory in partnership with the famous innovation center, CSEM, have the efficiency record for tandem silicon-perovskite solar cells.

This is significant as the researchers have surpassed the milestone of 30 percent for the first time using low-cost materials and established two certified world records, pushing the technology beyond the limits of silicon.

“We have passed a psychological barrier,” explains Christophe Ballif, Head of the EPFL Photovoltaics Laboratory and CSEM’s Sustainable Energy Center. “We have validated experimentally the high-efficiency potential of perovskite-on-silicon tandems. The 30 percent efficiency mark had already been achieved with other types of materials, namely III-V semiconductors. However, these materials and the processes used to make them are too expensive to sustain the energy transition – these devices are a thousand times more expensive than silicon solar cells.”

“Our results are the first to show that the 30 percent barrier can be overcome using low-cost materials and processes, which should open new perspectives for the future of PV,” he continued.

Breaking the limits and going beyond 

Solar cells are bound to the limits of whatever material they were made from. Today, silicon is the most widely used material for solar cells; however, despite its success, it does have its drawbacks as it has a theoretical efficiency limit of roughly 29 percent. This technology’s current efficiencies stand at a little less than 27 percent, giving a very small margin for potential efficiency advancements.

To overcome this barrier, scientists have added more complementary solar cells to silicon, resulting in “tandem” solar cells. The press release explains that the sun’s higher-energy visible light is absorbed in the top cell, while the lower-energy infrared light is absorbed in the silicon cell at the tandem’s rear. Halide perovskites reportedly have been discovered as an appropriate silicon partner as they can convert visible light to electrical power more efficiently than silicon alone. Moreover, they don’t increase fabrication costs significantly.

Tandem silicon-perovskite solar cells

The first consists of perovskite layers deposited from a liquid solution onto a flat silicon surface, which achieved a 30.93 percent efficiency for a 1 cm² test cell (0.2 in²).

The second one used a hybrid vapour and liquid solution approach to deposit perovskite onto a textured silicon surface, achieving a 31.25 percent efficiency for a 1 cm² solar cell.

According to the experts, more research is needed to determine how well the novel designs can be scaled up to greater surface areas. This could allow for scaling up to larger surface areas and ensure that these new cells can maintain a stable power output on our rooftops and elsewhere over a standard lifetime.

“Tandem perovskite-on-silicon technologies have been said to have the potential to exceed the 30% efficiency benchmark, but this is the first time this long-predicted potential has been demonstrated, which should hopefully pave the way for even cheaper sustainable electricity in the future,” Christian Wolff of EPFL said.

References: 

1. https://interestingengineering.com/innovation/in-a-world-first-perovskite-silicon-solar-cells-break-the-30-efficiency-barrier

No VAT on Solar Panels for the next 5 years

Published
November 16th, 2022

As part of the government’s Spring Statement 2022, Chancellor Rishi Sunak has announced that homeowner’s can now benefit from 0% VAT on energy efficient systems such as solar panels, heat pumps and insulation. This announcement comes after the energy price cap is set to rise to 54% and with the hope to help improve household energy efficiency whilst keeping energy costs down.

Solar panels are a great way to help lower household energy prices, all whilst generating carbon-free electricity. And now with the new tax relief, solar panels have never been viable  for homeowners. According to Chancellor Rishi Sunak, “A family having a solar panel installed will see tax savings worth over £1,000 and savings on their energy bill of over £300 per year.”

VAT and Solar Panels 

Whilst VAT is typically charged at the standard rate of 20%, up until now, homeowners would pay a reduced rate of 5% to a list of “energy-saving materials”. In order to encourage homeowners to invest in green technologies such as Solar PV. Previously, to benefit from the reduced 5% VAT rate, the cost of the equipment must not exceed more than 60% of the total installation. This threshold was mainly put into place for installations that included both solar panels and battery storage.

Whist Solar panels are on the list for “energy-saving materials”, battery storage systems still haven’t made the cut. With VAT on solar batteries still remaining at 20%. Whilst batteries are not a low-carbon technology, they have the ability to connect to low-carbon technologies and help support the shift towards energy independency. What’s more, they help increase the amount of renewable energy you can actually use within your home and your solar savings. This is why here at Deege Solar we always advise installing a battery storage system alongside your solar panel installation, in order to get the best value for money. However, we are aware that not everyone can afford the extra investment.

References: 

1. https://www.deegesolar.co.uk/zero_vat_on_solar_panels/ 

Owl Hatch Farm PV Park,

About GreenLight Services

Owls Hatch Solar PV Park is a 49.9MW solar PV power project. It is located in England, the UK. The project is currently active. It has been developed in single phase. 

Owls Hatch Solar PV Park is a ground-mounted solar project which is spread over an area of 213 acres.

The project supplies enough clean energy to power 12,600 households. The project cost is $76.295m.

GreenLight was part on the installation and testing team on site.