APBN New Site

APBN Developing Site

New Record Set for Solar Cell Technology Efficiency

These solar cells, composed of perovskite and organic materials, can achieve a power conversion efficiency of 23.6 per cent, potentially applicable for powering blinds, boats, and vehicles.

National University of Singapore researchers and their newly developed perovskite/organic tandem solar cells. Photo Credit: National University of Singapore.

With the growing threat of climate change and resource scarcity, sustainable development has become the primary agenda and overarching paradigm of most economies. In recent years, solar cell technologies have become a popular option as a sustainable source of energy. However, commercialising and normalising the usage of solar energy on a global scale requires affordable, durable, efficient, and reliable solar cells.

The current dominating solar technology in the solar photovoltaic market are silicon solar cells, which are based on a single-junction architecture. In industrial production, the practical power conversion efficiency of single-junction solar cells is capped at approximately 27 per cent. To raise the power conversion efficiency of solar cells above 30 per cent, at least two stacks of absorber layers (multi-junction cells) are needed, hence the rising interest in tandem solar cells which make use of two different types of photovoltaic materials.

Pushing the frontiers of solar energy production, scientists at the National University of Singapore have set a new record in the power conversion efficiency of solar cells made of perovskite and organic materials. With a power conversion rate of 23.6 per cent, their novel creation is a significant improvement from the average 20 per cent conversion rate reported by other studies on perovskite/organic tandem solar cells.

“Technologies for clean and renewable energy are extremely important for carbon reduction. Solar cells that directly convert solar energy into electricity are among the most promising clean energy technologies. High power conversion efficiency of solar cells is critical for generating more electrical power using a limited area and this, in turn, reduces the total cost of generating solar energy,” explained lead researcher Presidential Young Professor Hou Yi from the NUS Department of Chemical and Biomolecular Engineering.

“The main motivation of this study is to improve the power conversion efficiency of perovskite/organic tandem solar cells. In our latest work, we have demonstrated a power conversion efficiency of 23.6 per cent – this is the best performance for this type of solar cells to date,” added first author Dr. Chen Wei, Research Fellow at the NUS Department of Chemical and Biomolecular Engineering.

Despite being an attractive technology for next-generation thin-film photovoltaics, perovskite/organic tandem solar cells generally have lower efficiency compared to other types of tandem solar cells. In the study, the scientists found a way around this problem by developing a novel and effective interconnecting layer (ICL).

Tandem solar cells are generally made of two or more sub-cells that are electrically connected using ICL. The ICL is a crucial factor in determining the performance and reproducibility of a device. Ideally, the ICL should be chemically inert, electrically conductive, and optically transparent. The ICL developed by Hou and colleagues reduces electrical, optical, and voltage losses within the tandem solar cell, thereby improving the efficiency of the perovskite/organic tandem solar cells.

Given these optimistic results, the researchers believe that their technology will lay the groundwork for flexible, lightweight, low cost, and ultra-thin photovoltaic cells which could potentially power boats, blinds, and vehicles among other applications.

“Our study shows the great potential of perovskite-based tandem solar cells for future commercial application of photovoltaic technology. Building on our new discovery, we hope to further improve the performance of our tandem solar cells and scale up this technology,” said Assistant Professor Hou. [APBN]

Source: Chen et al. (2022). Monolithic perovskite/organic tandem solar cells with 23.6% efficiency enabled by reduced voltage losses and optimized interconnecting layer. Nature Energy.