In recent years, the quest for next-generation solar energy technologies has led researchers to explore innovative materials and device architectures that can surpass the limitations of conventional photovoltaic systems. Among these, perovskite/silicon tandem solar cells have emerged as a promising candidate to achieve higher power conversion efficiencies by combining the excellent light absorption properties of perovskites with the proven stability and established technology of silicon solar cells. A groundbreaking study by Yang et al., published in Nature Communications in 2025, unveils a novel approach using amphoteric coplanar conjugated molecules that significantly enhance the efficiency and stability of these tandem devices, potentially accelerating their commercial viability.
The core challenge in tandem solar cells lies in the efficient and stable interconnection between the perovskite top cell and the silicon bottom cell. Conventional interfacial layers often suffer from chemical incompatibility, energy level mismatches, and environmental degradation, all of which impede the device’s performance and longevity. Yang and colleagues address these challenges by synthesizing amphoteric coplanar conjugated molecules tailored for optimal electronic alignment and robust chemical interaction at the interface between the two absorber layers. This infiltration of molecular design into device engineering represents a significant leap forward in tandem solar technology.
Amphoteric molecules possess both electron-donating and electron-accepting functional groups, which confer versatile charge transport characteristics. By incorporating these molecules into the interface, the researchers achieved improved charge extraction and reduced recombination losses, thereby boosting the overall device efficiency. The coplanar structure of these conjugated molecules is particularly important—its planar configuration facilitates π-π stacking and strong intermolecular interactions, enhancing charge mobility and stability under operational conditions. This molecular architecture enables a seamless electrical bridge between the perovskite and silicon layers that is both efficient and durable.
The researchers utilized advanced spectroscopic and microscopic techniques to characterize the molecular orientation, energy level alignment, and chemical stability of these interfacial layers. Ultraviolet photoelectron spectroscopy (UPS) confirmed that the energy levels of the amphoteric molecules were well-aligned with the conduction bands of perovskite and silicon, facilitating efficient electron transfer. Meanwhile, X-ray diffraction and atomic force microscopy revealed that the coplanar molecules formed uniform, defect-minimized films, crucial for mitigating charge traps that typically limit device performance.
Stability testing under accelerated aging protocols demonstrated remarkable resilience of the tandem devices featuring the amphoteric molecular layers. Unlike traditional organic interlayers that degrade within hundreds of hours, these newly developed materials maintained over 90% of their initial efficiency after extended illumination and thermal stress. This outstanding durability arises from the chemical robustness of the amphoteric molecules and their strong adherence to both the perovskite and silicon substrates, effectively suppressing common degradation pathways such as moisture ingress and ion migration.
The power conversion efficiency (PCE) achieved by these tandem devices is among the highest reported to date. Yang et al. report champion devices reaching PCE values surpassing 29%, accompanied by negligible hysteresis and exceptional operational stability. Such performance benchmarks place this technological development at the forefront of photovoltaic research and promise tangible impact on the solar industry, where tandem cells are poised to dethrone single-junction silicon cells as the dominant technology.
Beyond performance metrics, the synthetic strategy employed for these amphoteric coplanar conjugated molecules is scalable and compatible with solution processing, offering a cost-effective and industry-friendly pathway for device fabrication. Unlike complex vacuum deposition techniques, solution-based methods can potentially lower manufacturing costs and facilitate the widespread adoption of tandem solar technologies. This compatibility with established fabrication protocols ensures that the materials are not just scientifically intriguing but also practically viable.
The integration of these molecules also brings into focus the fundamental understanding of interfacial phenomena in hybrid photovoltaic systems. By marrying precise molecular engineering with device physics, this work provides critical insights into the role of molecular design in controlling charge dynamics and stability at heterojunction interfaces. These insights could inspire a new generation of tailored interfacial materials across diverse optoelectronic applications, including light-emitting diodes and photodetectors.
Moreover, the amphoteric nature of the molecules introduces a level of tunability previously unexplored in tandem interfaces. By modulating the relative strengths of electron-donating and -accepting segments, one can fine-tune the molecules’ electronic properties to match different perovskite compositions or silicon architectures. This adaptability could accelerate customization of tandem devices for various spectral regions and operational environments, opening avenues toward fully optimized multi-junction solar cells with unprecedented efficiencies.
In addition to their electrical benefits, the coplanar conjugated molecules contribute to morphological stabilization of the perovskite layer by mitigating ion migration—a key degradation mechanism plaguing perovskite solar cells. The structural coherence and chemical passivation provided by these molecules alleviate interfacial instabilities that often trigger phase segregation and decomposition. As a result, the tandem devices exhibit extended operational lifetimes that meet the rigorous standards demanded for commercial deployment.
The research team further validated their findings through detailed device modeling and simulations that correlated molecular properties with device-level performance. Their models corroborate the experimental observations by demonstrating how optimal energy level alignment and reduced recombination rates translate directly into enhancements in open-circuit voltage and fill factor. This intersection of theory and experiment underscores the sophistication and robustness of their approach.
While the work primarily focuses on perovskite/silicon tandem cells, the implications extend to broader hybrid photovoltaic architectures. The principles established here—molecular amphoterism, coplanar conjugation, and interfacial engineering—could be extrapolated to other emerging photovoltaics including organic/organic tandems or perovskite/organic combinations. In doing so, this research opens new paradigms in multifunctional molecular design for energy conversion technologies.
As the quest for sustainable energy intensifies, innovations such as those presented by Yang et al. will be pivotal in bridging the gap between laboratory breakthroughs and real-world applications. Their research not only advances our fundamental understanding but also addresses practical challenges in device fabrication, operational stability, and performance scalability. This milestone paves the way toward affordable, high-efficiency, and durable tandem solar cells that could power the future energy landscape with unprecedented effectiveness.
Looking forward, further refinements in molecular design and interface engineering may unlock even higher efficiencies and longer lifetimes, while integration with flexible substrates and tandem configurations could expand the applicability of these technologies. Collaborations between synthetic chemists, device physicists, and industrial engineers will be essential to translate these scientific advances into commercial devices that can be mass-produced and deployed globally.
In summary, this seminal study introduces amphoteric coplanar conjugated molecules as a transformative class of interfacial materials, enabling perovskite/silicon tandem solar cells to reach new heights in efficiency and stability. Its marriage of innovative chemistry and photovoltaic technology represents a paradigm shift that stands to reshape the solar energy landscape and fast-track the adoption of next-generation tandem photovoltaics worldwide.
Article Title:
Amphoteric coplanar conjugated molecules enabling efficient and stable perovskite/silicon tandem solar cells
Article References:
Yang, D., Fahadi, B., Jia, X. et al. Amphoteric coplanar conjugated molecules enabling efficient and stable perovskite/silicon tandem solar cells. Nat Commun 16, 7745 (2025). https://doi.org/10.1038/s41467-025-62700-2
