Emerging photovoltaic technology has long been dogged by complex preparation, high cost and poor stability. New PSC could be manufactured on a large scale competitively, team reported in Science journal. — SCMP
Chinese scientists have developed a method to manufacture more advanced solar cells on a large scale and for a better price, according to the researchers who are looking to a future with more accessible and affordable solar energy.
With global carbon emissions increasing year by year, the development of clean energy such as solar cells is attracting a lot of attention.
The high-performing perovskite solar cell (PSC) is an emerging photovoltaic technology but it has long been dogged by complex preparation, its high cost and instability.
However, scientists at the Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST) in China, and from the Swiss Laboratory of Photonics and Interfaces at the École Polytechnique Fédérale de Lausanne have proved greater PSC stability when the technology is scaled up.
Their paper detailing the research was published in the peer-reviewed journal Science on January 19.
“Although the power conversion efficiency of some PSCs can now exceed 25%, such high efficiencies have been obtained only with small-area PSCs,” said Professor Li Yong of HUST, a leading author of the paper.
“(As the surface area increases), film unevenness, energy losses from photocurrent collection and instability of the film escalate steeply with device area. Larger-area devices often have substantial performance losses,” he said.
The team improved the situation by introducing a fullerene derivative chemical agent called CPPA. It consolidates the crystal structure of perovskite films and enhances the tolerance of the film against illumination, heat, and moisture.
Besides achieving unprecedented operational stability, the team said their new PSC could be manufactured on a large scale competitively with an improved vacuum flash solution-processing method that spread “perovskite inks” on the mould for the rapid crystallisation of perovskite films.
Both theoretical and practical results provided evidence of CPPA’s effects.
The fabrication of high-performance PSCs will also require both cutting the processing time and increasing the conductivity and stability of the hole-transporting layer, a critical component that contributes to how perovskite film conducts.
Researchers change the components of a solution in the processing of hole-transporting layers, effectively making it more stable. In laboratory ageing tests, the surface of the improved film remained smooth, while voids, microdefects and particles emerged on the original film.
With the new manufacturing strategy, the team boosted stability and accelerated the electronic charge transport of the film which achieved a satisfying power conversion efficiency of 23.5%.
The film retained 95.5% of its initial efficiencies after 3,265 hours at maximum power under continuous illumination at 70 degrees Celsius (158 Fahrenheit).
The researchers noted the potential, saying these approaches allowed them to create efficient perovskite solar modules with outstanding long-term operational stability.
“The holistic strategy for stabilising the perovskite/HTL heterostructure provides promising technical routes for fabricating efficient and stable perovskite solar modules,” Li said in the paper. – South China Morning Post
