Future looks bright as new Chinese-designed solar cell provides renewable energy breakthrough

Chinese researchers have developed a new type of solar cell using perovskite, which is more efficient than the current silicon-based cells
They have managed to overcome stability issues that previously stopped perovskite from being used in solar energy

Science

Zhang Tongin Beijing

Published: 12:00pm, 29 Oct 2023

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In a landmark achievement that could reshape the renewable energy landscape, a team of Chinese researchers has developed a new type of solar cell with groundbreaking efficiency, unprecedented stability and an extended service life.

The technology could also reduce energy costs to a quarter of that of current silicon-based solar cells, according to the team.

The new solar cells use perovskite, a low-cost, easily available inorganic material. When exposed to sunlight, perovskite converts solar energy into electricity in a similar way to traditional solar panels, but with higher efficiency.

While perovskite solar cells (PSCs) have long shown promise for surpassing the efficiency limits of silicon-based cells, their thermal and chemical stability have been problematic. Typically, they degrade rapidly when exposed to oxygen and moisture or when operated at high temperatures.

The newly developed perovskite solar cell boasts a power conversion efficiency (PCE) of 25.6 per cent. Impressively, the cell retained over 90 per cent of its initial efficiency after 1,200 hours of operation at 65 degrees Celsius (149 degrees Fahrenheit).

The research, spearheaded by Professor Zhu Zonglong from City University of Hong Kong, in collaboration with Li Zhongan from Huazhong University of Science and Technology, was published on October 20 in the peer-reviewed journal Science.

“Our study provides theoretical guidance for the design of efficient and stable PSCs and paves the path for facile access to commercially available PSCs,” the team said in the paper.

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The team’s breakthrough lies in the improvement of an interfacial layer between the photoactive layer and the anode of the solar cell.

Previous study found using self-assembled monolayers (SAMs) as an interfacial layer generally raises the PCE to above 25 per cent. However, with the monomolecular structure, SAM is only 1-2nm thick and is easily decomposed at high temperatures.

“We designed the SAM in a unique three-dimensional structure and anchored it to a stable nickel oxide film to enhance both thermal and chemical stability. This development effectively boosts the cell’s lifetime performance and energy conversion capabilities,” Zhu said on Tuesday.

“Although the lab-tested devices are relatively small, the fabrication methods are simple and highly scalable, indicating suitability for large-scale production. We estimate that the Levelised Cost of Electricity (LCOE) for our new solar cells could be as low as US$5.45 per MWh, significantly lower than the US$24 per MWh for silicon-based solar cells,” he said.

China is already a leader in the photovoltaic (PV) industry, exporting more than four billion solar cells in 2022, with a total export value of US$46.38 billion, according to customs data. And the Chinese PV industry’s global market share exceeds 80 per cent in all aspects, from raw materials to production equipment, according to the China Photovoltaic Industry Association (CPIA) website.

Perovskite solar cells under high temperature ageing (left), and perovskite solar cells with novel SAM. Photo: CityU

“The global energy landscape is shifting to prioritise solar and wind power. Solar power has become the cheapest energy source worldwide with costs dropping over 90 per cent in the past decade. China’s solar industry is willing to make more efforts to address climate change and boost economic growth,” CPIA spokesman Liu Yiyang said in August.

Professor Zhu believes PSCs have broad applications.

“Though related research started relatively late, perovskite solar cells have made significant strides in stability and lifespan in recent years, moving from just a few hours at low temperatures to thousands of hours at high temperatures,” he said.

“PSCs can be used in darker conditions and, through modification, they can absorb light of different wavelengths. This superior versatility makes them ideal for use in flexible devices, transparent solar cells, bifacial solar cells and indoor photovoltaics.

“Additionally, they are more cost-effective and environmentally friendly than traditional silicon cells, which will help reduce the environmental impact of the photovoltaic industry,” he said.

Chinese scientists boost perovskite solar cell efficiency

Meanwhile, a researcher from Sealand Securities said work was still needed before the perovskite cells could be more widely used.

“To use perovskite solar cells widely, the industry need to make them more stable and long-lasting, produce large, high-quality panels, and get government support like subsidies or tax breaks,” said the researcher, who declined to be named.

Zhu believes that once the technology matures, perovskite may drive a new wave of growth in the global photovoltaic market, especially in China.

“At that time, energy costs will be further reduced, the entry of new investors will lead to a significant increase in installed capacity, and China’s photovoltaic products may become more competitive due to higher efficiency and lower costs, thereby potentially increasing the export volume of China’s photovoltaic products,” he said.

Several established Chinese companies, including Renshine Solar, Microquanta and GCL Perovskite, are already making moves to expand their perovskite solar cell production capacities.