Lingnan University Scholars Co-Develop Record-Breaking Interfacial Structure for Highly Efficient Tandem Solar Cells, Published in Nature Communications

In response to the global demand for clean energy transition, tandem solar cells are recognised as a crucial next-generation technology that will significantly improve solar power efficiency. Scholars from Lingnan University’s Wu Jieh Yee School of Interdisciplinary Studies (WJYSIS) and their collaborators have innovatively developed a novel interfacial structure, which substantially reduces energy loss and successfully overcomes the current limitations of perovskite solar cells in voltage, further improving the efficiency of converting sunlight into electricity. Their findings, published in the top-tier international journal Nature Communications, affirm Lingnan University’s research capabilities in the fields of renewable energy materials and photovoltaic technology.

Conventional strategies often lead to the uncontrolled diffusion of ligand molecules into the perovskite bulk or their severe loss during solvent washing, failing to form an effective ligand layer. The research team proposes a novel strategy that successfully immobilises the ligand molecules onto the SAM molecules, constructing a localised 2D/3D structure.

The joint research team, comprising Prof Chen Xi, Dean of the WJYSIS and Chair Professor of Interdisciplinary Studies at Lingnan University; Prof Wu Shengfan, Assistant Professor (Presidential Early Career Scholar) of the WJYSIS at Lingnan University, and colleagues from the City University of Hong Kong, has developed a novel method to form a localised 2D/3D structure within the perovskite solar cell, reducing energy loss and improving charge extraction efficiency and interfacial contact. At the same time, by utilising tandem solar cell technology, in which the top material absorbs short-wavelength light and the bottom material absorbs long-wavelength light. This arrangement substantially improves light utilisation efficiency.

The figure illustrates the novel SAM molecule designed by the team, named CbzBT-B. This molecule exhibits excellent stability, and its energy levels are better aligned with the perovskite. The sulfur atoms within this molecule can interact with the ligands, ensuring the formation of a localised 2D/3D perovskite heterojunction structure at the bottom interface.

The team explained that this innovative technology optimises the solar cell in multiple ways. Firstly, it improves the quality of the thin film, allowing this light-absorbing material to grow more uniformly, thereby reducing intrinsic defects. Secondly, the technology greatly reduces defect density at the interfaces, suppressing undesirable energy loss and thus minimising voltage loss. The technology also improves the energy level alignment at the interface, enabling more efficient charge extraction.

Solar cell test results indicate that wide-bandgap perovskite solar cells employing this strategy achieve significant enhancements in open-circuit voltage and efficiency, while exhibiting excellent operational stability. This strategy is applicable to various wide-bandgap perovskite solar cells and has broken multiple performance records. Based on this, the team fabricated tandem solar cells, achieving a high efficiency of 27.11 per cent.

The research team has successfully developed highly efficient and stable wide-bandgap perovskite solar cells, setting multiple cell performance records. The cell demonstrated excellent performance during long-term operational testing, maintaining over 95 per cent of its efficiency even after continuous operation for 700 hours. According to the team’s projections, the efficiency of this cell can still be maintained at over 90 per cent after 1,800 hours of long-term operation. Meanwhile, based on this technology, the power conversion efficiency of the perovskite-organic tandem solar cell reaches 27.11 per cent, among the highest efficiencies for this type of tandem solar cells.

Prof Chen Xi, Dean of the WJYSIS and Chair Professor of Interdisciplinary Studies at Lingnan University.

Prof Wu, co-corresponding author of the paper, said “This achievement builds upon our sustained and in-depth exploration of interface engineering and tandem photovoltaic devices. It provides a reliable foundation for future large-scale applications. We will continue to drive the advancement of related technologies toward commercialisation, transforming efficient and stable energy solutions into commercial products to address climate challenges and energy security needs, contributing to societal sustainable development.”

Prof Wu Shengfan, Assistant Professor (Presidential Early Career Scholar) of the WJYSIS at Lingnan University.

Prof Chen Xi commended the outcome highly, saying “Lingnan has been actively promoting interdisciplinary research in recent years. This breakthrough demonstrates the University’s strengths and commitment to tackling global energy challenges and developing clean energy technologies. Our team will continue to transform innovative research achievements into practical solutions, supporting the global transition towards a green and low-carbon future.”

The research paper was published in the top-tier international journal Nature Communications. Read the full study here: Localized 2D/3D heterojunction enhances photovoltage for perovskite-organic tandem solar cells.

To understand their awareness of and interest in the Chinese tea culture, the Asia-Pacific Institute of Ageing Studies at Lingnan University conducted a public opinion survey and analysis of the tea consumption habits of young people in the Hong Kong SAR. The findings show that more than three quarters of respondents drink Chinese tea regularly. However, as many as half also drink “flavoured tea” with sugar, floral flavours or milk frequently. The proportion of young people who drink tea regularly was significantly higher than soft and speciality drinks, although more than one third were unfamiliar with the health benefits of tea. Scholars point out that parents exert a strong influence on young people’s tea-drinking habits and suggest that different sectors of society might organise intergenerational activities to pass the Chinese tea culture on to younger generations.

Between March and July 2025, the researchers circulated a questionnaire to 488 Hong Kong SAR residents aged between 12 and 39 to find out how much they know about Chinese tea and related beverages and how much they drink. More than three quarters (76.2%) of respondents drink Chinese tea regularly, and the largest proportion (33.8%) drink Chinese tea one to four times a month Although this was a higher proportion than for coffee (25%), it remained lower than for other beverages. As many as 53.4 per cent of respondents consume speciality drinks such as bubble tea and fruit tea one to four times per month, followed by freshly squeezed juice (42.9%), soft drinks (39.6%), and packaged or bottled juice (38.1%).

The proportion of respondents who drank Chinese tea 11 or more times a month was 25.4 per cent, the highest of all beverage categories, surpassing coffee (17.5%), packaged or bottled juice (17.5%), soft drinks (14%), speciality drinks (10.8%), and freshly squeezed juice (6.3%), which suggests that some young people have developed a regular habit of drinking tea in the long-term (Figure 1).

Figure 1: The largest proportion of young respondents reported drinking Chinese tea one to four times a month (33.8%).

Regarding their preferences, young respondents usually preferred pu-erh (65%), followed by tieguanyin (49%) and jasmine tea (31%). However, nearly half of respondents (49%) also drink flavoured teas containing sugar, floral flavours or milk frequently (Figure 2), reflecting increasingly blurred boundaries between traditional and modern teas in younger generations.

Figure 2: Nearly half the respondents (49%) drink flavoured tea containing sugar, floral flavours or milk regularly.

When asked whose opinions influenced their choice of tea, 39.7 per cent of respondents said that their parents had a “great” or “strong” influence. By comparison, the influence of their friends (11.4%) and social media (11%) was much less (Figure 3), which shows the stronger role of families in passing on the Chinese tea culture to younger generations.

Figure 3: 39.7 per cent of young respondents said that their choice of tea was influenced to a “high” or “strong degree” by their parents.

The most common reasons for choosing a tea were the “aroma” (55%) or “taste” (50%). Nearly half (47%) also cited “family customs” - more than those who associated Chinese tea with “health benefits” (37%), “cultural identity” (19%), or “emotional stability” (17%) (Figure 4).

Figure 4: When asked why they drink tea, respondents usually said “aroma” (55%) or “taste” (50%).

However, young people who drink tea have a limited understanding of its health benefits. More than one third of respondents (34.1%) said that they “knew nothing about” or had “only heard of” these benefits of tea, and nearly half (44.2%) that they “knew nothing about” or had “only heard of” Chinese tea brewing techniques. The study also found that nearly 70% of respondents (68.1%) expressed “average”, “considerable”, or “very strong” interest in learning tea arts, which shows that although the Hong Kong younger generation’s knowledge of Chinese teas is limited, they are generally interested in learning more.

Prof Dickson Chan Chak-Kwan, Research Professor and Director of Asia-Pacific Institute of Ageing Studies at Lingnan University, said that traditional Chinese tea processing techniques and associated social practices were inscribed on the United Nations Educational Scientific and Cultural Organisation (UNESCO) Representative List of the Intangible Cultural Heritage of Humanity in 2022. He noted that while the Chinese Mainland has actively promoted tea culture education for young people, the Hong Kong SAR still does not really understand the health benefits of tea or how to brew it, adding “Promoting tea culture helps pass on the essence of Chinese culture to younger generations. The study finds that parents have a great influence on forming the habit of tea drinking in their children, and recommends that primary and secondary schools and cultural organisations undertake activities that encourage parents and children to learn about Chinese tea together, so that tea drinking is encouraged and the cultural heritage of Chinese tea more effectively passed on to young people.”

Lingnan study finds more young people drink tea than soft drinks regularly. Generated picture.

Prof Chan also suggested that the education sector make the most of young people’s interest in the tea arts to develop their understanding of Chinese tea culture. Flavoured teas may initially build public awareness of the differences between pure and sugar-sweetened flavoured teas, reduce dependency on sugary beverages, and in the long run help promote a healthier diet.

"Research on Tea Consumption among Youth in Hong Kong" is part of the "Chinese Tea Promotion in Young People " Project (2024-2026). The project is sponsored by the Tin Ka Ping Foundation and aims to promote Chinese tea arts among young people and the public in Hong Kong through seminars and tea appreciation workshops, to encourage the understanding of Chinese traditional culture and promote physical and mental well-being.