Breakthrough solar cells reach 12.2% record efficiency with new additive

Researchers from a South Korean university have found a way to significantly boost the efficiency of perovskite solar cells. The team, led by a professor from Chung-Ang University, used a special additive for densely packed perovskite solar cells, which resulted in a record efficiency of 12.22%.

Tin halide perovskites (Sn-HPs) are promising materials for next-generation solar cell technology. But, they still need to address issues related to stability and conversion efficiency.

Now the research team from Korea revealed that using 4-phenylthiosemicarbazide (4PTSC) as an additive can significantly enhance the performance and durability of Sn-HP-based solar cells by controlling crystal formation, passivating defects, and protecting the material from oxidation and moisture. These findings could pave the way for more accessible solar energy.

Multiple functionalities of 4PTSC in solar cells

Through extensive analyses and experimental comparisons between regular Sn-HP PSCs and those containing the proposed additive, the researchers showcased the multiple functionalities of 4PTSC as an additive.

“We purposely chose a multifunctional molecule that acts as a coordination complex and a reducing agent, passivates defect formation, and improves stability,” explained Associate Professor Dong-Won Kang from Chung-Ang University.

In particular, tin halide perovskites (Sn-HPs) serve as powerful alternatives to the exceptionally high-performing lead (Pb)-based perovskites. Given that Sn is significantly less toxic to the environment than Pb, research into Sn-HPs is a worthwhile endeavor.

Unfortunately, perovskite solar cells (PSCs) made from Sn-HPs still face several challenges that need to be addressed. Specifically, the rapid and disordered crystallization during production leads to the formation of defects in the crystal structure of the perovskite layer, which hampers conversion efficiency.

Additionally, Sn-HPs suffer from low stability and high sensitivity to moisture and ambient conditions, limiting the overall lifetime of PSCs made from them. However, the new research by the Korean team has found the elegant and efficient solution to these issues by introducing 4-Phenylthiosemicarbazide (4PTSC) as an additive during the production of Sn-HPs.

Sn-HPs are relatively inexpensive to manufacture

Using this powerful additive, the researchers were able to produce PSCs with unprecedented performance.

“The 4PTSC-modified devices achieved a peak efficiency of 12.22% with an enhanced open-circuit voltage of 0.94 V and exhibited superior long-term stability, retaining almost 100% of the initial power conversion efficiency, even after 500 h and about 80% after 1200 h in ambient conditions without any encapsulation,” said Kang.

“This is different from the marked degradation observed in control devices within the first 300 h.”

Given that Sn-HPs are relatively inexpensive to manufacture and demonstrate good performance and great durability, the findings of this study could pave the way to more accessible and long-lasting solar panels. In turn, this can help in making energy cheaper for the general population while staying in line with current sustainability goals.

“Addressing the key challenges of Sn-HPs and significantly improving their performance aligns with our goal of contributing to developing efficient and sustainable renewable energy solutions, thereby advancing green technologies and promoting a sustainable future, “ added Kang.

Their study was originally published in the journal Advanced Energy Materials .