TL;DR
Researchers have created an all-perovskite tandem solar cell without PEDOT:PSS, achieving a record 29.1% efficiency. This development addresses stability issues and advances solar technology.
Researchers from the Hong Kong University of Science and Technology (HKUST) have developed a new all-perovskite tandem solar cell that does not use PEDOT:PSS, achieving a record efficiency of 29.1%.
Get the latest gadgets delivered free with Prime
- Fast, free delivery on millions of items
- Prime Video, Amazon Music and more included
- Member-only deals all year
The team replaced the conventional PEDOT:PSS hole transport layer with a phenothiazine-functionalized self-assembled monolayer called 4PAPT, which promotes better crystallization, stability, and charge transport in the device.
This innovation resulted in faster, more uniform perovskite film formation, reduced defect density, and improved interfacial stability, leading to higher overall efficiency and enhanced durability. The device retained 90% of its initial efficiency after over 800 hours of operation under simulated sunlight.
Implications for Stability and Efficiency in Perovskite Solar Cells
This development is significant because it addresses long-standing stability issues associated with PEDOT:PSS, a common hole transport layer in perovskite devices, which can degrade over time due to moisture sensitivity. By eliminating PEDOT:PSS, the new design offers a pathway to more durable, high-efficiency solar cells that are potentially easier and cheaper to manufacture, advancing commercial viability.
Achieving 29.1% efficiency in a PEDOT:PSS-free tandem device marks a new record, demonstrating that interface engineering can substantially improve performance and stability, critical factors for real-world applications.
Products Worth Considering

Anker SOLIX C1000 Gen 2 Portable Power Station with 200W Solar Panel

Jackery Explorer 300 Portable Power Station with 40W Solar Panel, 292Wh

Jackery Explorer 2000 v2 Portable Power Station with Two 200W Solar Panels
As an affiliate, we earn on qualifying purchases.
Advances in Perovskite Tandem Solar Cell Technology
Perovskite solar cells have rapidly advanced, with tandem configurations surpassing efficiencies of 28%. However, stability remains a key challenge, especially related to interface materials like PEDOT:PSS, which can absorb moisture and promote phase segregation during crystallization.
Previous efforts focused on improving material stability and interface quality. The recent study from HKUST builds on these by replacing PEDOT:PSS with a molecularly engineered monolayer, enabling higher efficiency and longer operational lifetime.
“Replacing PEDOT:PSS with a molecularly designed self-assembled monolayer allowed us to control crystallization, improve stability, and reach record efficiencies in all-perovskite tandem solar cells.”
— Fengzhu Li, HKUST
Remaining Questions on Long-Term Stability and Scalability
While the device demonstrated over 800 hours of stability under laboratory conditions, it is still unclear how it will perform over longer periods and under real-world environmental stresses. Further testing is needed to assess long-term operational stability, scalability of the fabrication process, and cost-effectiveness for commercial production.
Next Steps Toward Commercial Application and Further Optimization
Researchers plan to conduct extended durability testing under outdoor conditions and explore scaling the manufacturing process. Additional work will focus on integrating the new interface materials into larger modules and evaluating long-term stability in real-world settings.
Key Questions
What makes this solar cell different from previous perovskite devices?
This solar cell replaces the commonly used PEDOT:PSS layer with a molecularly engineered monolayer, leading to higher efficiency and improved stability.
Why is removing PEDOT:PSS important?
PEDOT:PSS can absorb moisture and promote phase segregation, degrading device performance over time. Removing it enhances durability.
Can this technology be scaled for commercial use?
Further testing and development are needed to assess scalability and long-term stability under real-world conditions.
How does the efficiency of 29.1% compare to other solar technologies?
It is among the highest for all-perovskite tandem solar cells and represents a significant improvement over previous PEDOT:PSS-based devices.
Source: PV Magazine
