Despite these advances, a comprehensive understanding of the fundamental mechanisms dictating the interaction between perovskites and HCMs has remained elusive. The challenge lies in deciphering how the energy levels at the critical interfaces—specifically between the electrode, hole-collecting monolayer, and the perovskite layer—align in order to facilitate efficient charge transport. Historically, theories such as vacuum level alignment, Fermi level alignment, and the electrode-modified Schottky model have been employed in various contexts, often without rigorous validation. This lack of a unified framework has hindered the rational design of HCM materials, forcing researchers to rely heavily on empirical trial and error, slowing progress in device optimization.

Addressing this vital gap, a pioneering research group led by Professor Hiroyuki Yoshida at Chiba University has formulated the first universal model capturing the nuanced energy level alignments at electrode/HCM/perovskite junctions. Published in the Journal of Materials Chemistry A in March 2026, their transformative work systematically elucidates the fundamental parameters that determine hole collection efficiency across diverse material systems. Collaborating with scientists from Kyoto University and The University of Electro-Communications in Japan, the team employed state-of-the-art spectroscopic techniques to underpin their theoretical framework with precise experimental data.

Utilizing ultraviolet photoelectron spectroscopy (UPS) and low-energy inverse photoelectron spectroscopy (LEIPS), the researchers meticulously characterized the energy landscape of representative HCM and perovskite materials. These sophisticated methods enabled the precise determination of key electronic properties—namely, the work function (the energy gap between the Fermi level and vacuum level) and ionization energy (the minimum energy required to liberate an electron from a material’s surface to vacuum). Such quantitative insights were indispensable in constructing a physically consistent model applicable to a variety of device architectures.

The resulting model conceptualizes the electrode/HCM/perovskite boundary as two distinct interfaces. At the first interface, shared between the electrode and the hole-collecting monolayer, the critical governing phenomenon is the formation of an interface dipole. This electric field is primarily driven by the orientationally aligned molecular dipoles within the HCM, creating a directional and adjustable interfacial potential. Conversely, the junction between the hole-collecting monolayer and the perovskite is treated through the lens of semiconductor heterojunction theory, a cornerstone of conventional semiconductor electronics. Here, disparate materials with varying electronic properties interact, forming energy barriers and potential wells that influence charge movement.

Profoundly, the model identifies two paramount factors determining the efficacy of hole collection: band bending and interfacial energy barrier height. Band bending refers to the gradual variation in energy levels resulting from internal electric fields formed at heterojunctions, altering how charges traverse the interface. Meanwhile, the interfacial energy barrier height quantifies the energetic mismatch that can either facilitate or obstruct the flow of positive charges or “holes.” These parameters are elegantly shown to be derived from a handful of fundamental quantities—the work functions of the electrode and HCM, along with the ionization energy of the perovskite—offering a predictive blueprint for interface design.

Professor Yoshida highlights the power of this approach, stating that the model “successfully and self-consistently explains why certain hole-collecting monolayers result in superior solar cell performance, whereas others fall short.” Validation came through rigorous comparison with experimental datasets spanning a wide variety of materials, confirming the universality and robustness of the framework. This breakthrough paves the way for tuning interfacial properties with precision, effectively guiding the synthesis of new HCMs targeted to maximize device efficiency and stability.

Beyond merely serving as a diagnostic tool, the implications of this model are transformative for the solar cell industry. The ability to predict and optimize energy level alignment without exhaustive experimentation promises to accelerate the pace of innovation drastically. By providing clear guidelines for molecular design and material selection, the model is set to reduce development cost and time, thus hastening the commercialization of next-generation perovskite photovoltaic technologies boasting unprecedented power conversion efficiencies.

The study’s relevance also extends beyond photovoltaics. The foundational principles underlying the interface energetics are equally applicable to other semiconductor-based devices such as light-emitting diodes and transistors, which operate through similar charge transport mechanisms. This research thus lays critical groundwork in materials science, contributing broadly to the advancement of sustainable energy technologies vital to addressing global energy demands.

As Professor Yoshida concludes, “By establishing a new foundation for understanding and controlling electronic interfaces, our model not only optimizes solar cell performance but also opens new horizons for multifunctional semiconductor devices. This work exemplifies how fundamental science drives transformative technology in the renewable energy landscape.” The broader impact of this research is poised to resonate across multiple sectors, underscoring the critical role of interface engineering in the future of electronics.

The collaborative effort supported by leading Japanese scientific agencies such as JST–MIRAI and JSPS-KAKENHI underscores the high-priority investment in sustainable energy materials research. The profound insights yielded by the combination of experimental precision and comprehensive theory represent a beacon for future research directions in organic electronics and beyond. Researchers and technologists worldwide will undoubtedly draw upon these findings as they strive to unlock the full potential of perovskite solar cells.

In sum, the unveiling of this universal model for interfacing energy levels in perovskite solar cells signifies a landmark achievement that transcends disciplinary boundaries. Its holistic, data-driven approach embodies the next frontier in optimizing renewable energy harvesting materials—a crucial stride toward a cleaner, more energy-secure future.

Subject of Research:
Perovskite Solar Cells, Hole-Collecting Monolayers, Energy Level Alignment, Semiconductor Interfaces

Article Title:
A universal model for energy level alignment at interfaces of hole-collecting monolayers in p-i-n perovskite solar cells

News Publication Date:
March 14, 2026

Web References:
https://doi.org/10.1039/D5TA04749H
https://www.cn.chiba-u.jp/en/news/

References:
Akatsuka, A., Truong, M.A., Wakamiya, A., Kapil, G., Hayase, S., Yoshida, H. (2026). A universal model for energy level alignment at interfaces of hole-collecting monolayers in p-i-n perovskite solar cells. Journal of Materials Chemistry A. DOI: 10.1039/D5TA04749H

Image Credits:
Professor Hiroyuki Yoshida, Chiba University

Keywords

Perovskite solar cells, hole-collecting monolayers, energy level alignment, interface dipole, band bending, semiconductor heterojunction, photovoltaic efficiency, renewable energy, photoelectron spectroscopy, organic electronics, interface engineering, sustainable technology

Tandem solar cells (TSCs) are lauded for their potential to surpass the efficiency limitations of conventional single-junction solar devices by stacking two subcells with different bandgaps. Each subcell absorbs distinct segments of the solar spectrum, enabling more effective harnessing of sunlight. In the realm of all-perovskite tandem solar cells, however, practical implementation has faced formidable hurdles. Central among these challenges is the mismatched crystallization kinetics between the wide-bandgap (WBG) and narrow-bandgap (NBG) perovskite layers. This imbalance often leads to phase segregation and defect proliferation, detracting significantly from device efficiency and operational longevity.

To overcome these intrinsic difficulties, Professors GE Ziyi and LIU Chang, along with their research team, have devised a unified colloidal chemistry strategy that strikes a delicate balance in crystallization dynamics between the WBG and NBG perovskite subcells. This breakthrough leverages a meticulously designed modulation system based on graded carboxylate anions—specifically tartrate (Ta-) and citrate (Cit-) ions—that exert precise control over nucleation and crystal growth pathways in both subcells.

In the WBG subcell, the introduction of tartrate anions proves instrumental by stabilizing the coordination environment of Pb2+ ions. This stabilization suppresses unwanted phase segregation, fostering a more uniform and controlled crystalline lattice arrangement. Such uniformity is vital because it minimizes defect sites that can act as recombination centers for charge carriers, thus preserving the solar cell’s photovoltaic performance.

Conversely, in the NBG subcell—which typically suffers from Sn2+ defect states that act as non-radiative recombination centers—citrate anions play a dual role. They optimize Sn-I bonding within the colloidal precursor environment, effectively passivating the vulnerable Sn2+ defects. This passivation enhances the charge transport properties of the NBG layer, which is fundamental to maximizing the overall current output of the tandem device.

Amplifying the stabilizing effect, choline cations are introduced as synergistic agents, passivating undercoordinated metal ions at the interfaces between the crystal and colloid phases. This interface passivation is crucial for constructing a robust stabilization matrix that maintains heterojunction integrity during the critical nucleation and growth phases. The tailored colloidal precursor solution thus orchestrates a harmonized crystallization process across the tandem structure, ensuring optimized electronic and structural properties.

The resultant tandem solar cells demonstrate a phenomenal power conversion efficiency (PCE) of 29.76%, a value that is among the highest recorded for all-perovskite tandem architectures. Notably, this outstanding performance was independently certified with a measured PCE of 29.22%, underscoring the reproducibility and credibility of the method. The devices also showcase remarkable operational stability, sustaining over 90.2% of their initial efficiency after more than 700 hours of continuous exposure under maximum power point tracking—a rigorous test indicative of commercial viability.

Scaling up from lab-scale testing, the team fabricated a 1 cm² large-area tandem cell using their colloidal chemistry methodology. This larger device achieved a commendable PCE of 28.87%, demonstrating the strategy’s potential for practical deployment in industrial-scale photovoltaic manufacturing processes. The scalability factor is particularly significant because it addresses a fundamental bottleneck in transitioning high-efficiency perovskite technology from academic laboratories to accessible green energy solutions.

Beyond immediate performance gains, this research contributes a universal framework for tuning multijunction crystallization kinetics via chemical modulation. By aligning nucleation rates and mechanisms between the dissimilar perovskite layers, the approach mitigates deleterious defects while enhancing crystallinity and charge carrier dynamics. Such control at the colloidal precursor level marks a paradigm shift in perovskite processing, offering a path toward commercial all-perovskite tandem cells that can consistently deliver high efficiency with long-term stability.

The implications of this work resonate through the broader field of optoelectronics and renewable energy. With theoretical efficiencies for all-perovskite tandem solar cells predicted to exceed 40%, strategies like those pioneered here are vital stepping stones to surpassing current photovoltaic technology thresholds. Moreover, the chemical insight gained through the interplay of tartrate and citrate anions, coupled with choline cation synergy, reveals a new dimension of colloid chemistry manipulation that may inspire innovations beyond photovoltaics, potentially touching other areas such as light-emitting diodes and photodetectors.

Financial support for this landmark study was provided by prominent Chinese national initiatives, including the National Key Research and Development Program, the Young Scientists Fund of the National Natural Science Foundation of China, and the National Natural Science Foundation of China. This backing underlines the strategic importance attributed to cutting-edge energy materials research in addressing global energy challenges.

In summary, the integrated colloidal chemistry approach to tuning nucleation kinetics in all-perovskite tandem solar cells embodies a significant technological leap. By resolving the crystallization mismatches that have historically hampered tandem device performance, the team’s work not only pushes conversion efficiencies near the 30% mark but also lays the foundation for stable, scalable, and commercially viable perovskite photovoltaics. This development signals a hopeful horizon for next-generation solar technology poised to deliver affordable, high-efficiency renewable energy worldwide.

Subject of Research: Not applicable
Article Title: Tailoring Colloidal Precursor Chemistry for Tunable Nucleation Kinetics in All-Perovskite Tandem Solar Cells​
News Publication Date: 27-Mar-2026
Web References: 10.1016/j.joule.2025.102381
References: Provided in the article DOI and journal publication
Image Credits: NIMTE

Addressing these challenges requires innovative approaches that combine efficiency with environmental responsibility. Emerging at the forefront of such efforts is a revolutionary photovoltaic thermo-electro dual module system (PTEDMS) developed by a research collaboration between the Research Center for Eco-Environmental Sciences at the Chinese Academy of Sciences and China Jiliang University. This system merges photovoltaic (PV) solar energy utilization, electrical resistance heating (ERH), electrokinetic transport, and thermal energy storage into a seamlessly integrated platform designed for continuous, carbon-free soil remediation.

The core innovation of PTEDMS lies in its ability to optimize solar energy allocation through real-time machine learning algorithms. Unlike conventional remediation systems which rely heavily on fossil fuels or static power inputs, PTEDMS harnesses fluctuating solar irradiance efficiently, balancing the demands of both thermal and electrochemical remediation pathways without interruption. This dynamic management ensures pollutant degradation proceeds at maximum rates regardless of environmental variability, marking a significant step forward in smart, adaptive environmental engineering.

Electrical resistance heating (ERH) plays a seminal role within the PTEDMS framework by elevating subsurface temperatures through controlled Joule heating. This thermal uplift volatilizes and breaks down stubborn organic contaminants entrenched at various soil depths. Complementing ERH, electrokinetic transport enhances the mobility of ionic and molecular pollutant species within soil micropores, facilitating their migration towards treatment zones and stimulating native microbial communities that contribute to biodegradation processes. The synergy between thermal and electrokinetic mechanisms results in removal efficiencies roughly 46% higher than those achievable by either technology alone, while reducing energy consumption by approximately 20%.

A distinguishing feature of PTEDMS is its departure from battery-dependent energy storage systems. Instead, it employs a sophisticated hot water thermal storage subsystem that boasts energy exchange efficiencies surpassing 85%, facilitating uninterrupted operation during periods of diminished sunlight. This design circumvents issues of battery degradation and resource constraints, ensuring sustainable long-term deployment, particularly in sunny regions with limited access to reliable grid electricity.

The incorporation of pump-driven dynamic water cycling is pivotal for seamless power delivery. This innovation allows for flexible thermal energy transfer and management, thereby maintaining system operation during intermittent cloud cover or nighttime conditions. By coupling this physical component with intelligent software controls, PTEDMS exemplifies a next-generation hybrid remediation system that leverages both hardware and algorithmic sophistication to address one of the most persistent challenges in environmental restoration.

Machine learning forms an indispensable component of PTEDMS’s operational protocol. By continuously analyzing solar irradiance, soil contaminant profiles, and energy system parameters, algorithms dynamically allocate PV-generated energy between thermal heating and electrokinetic modules. This smart energy distribution not only maximizes pollutant breakdown, but also ensures the system adapts to site-specific geochemical conditions and pollutant heterogeneity, improving scalability and field applicability across diverse contaminated sites.

The environmental and economic implications of PTEDMS are vast. Its carbon-neutral operation aligns with pressing international climate commitments while offering industry and municipalities cost-effective solutions for long-term rehabilitation. Deployment of PTEDMS directly reduces reliance on fossil fuels, mitigates carbon emissions associated with conventional soil remediation, and fosters sustainable ecosystems, directly benefiting public health and agricultural productivity.

This technology holds substantial promise beyond soil remediation alone. The dual-module approach, with its inherent flexibility and renewable integration, can be adapted for wastewater treatment, restoration of contaminated agricultural lands, and broader eco-engineering applications. By marrying renewable energy technologies with cutting-edge digital intelligence, PTEDMS represents a paradigmatic shift towards scalable environmental technologies designed to meet global sustainability goals.

Dr. Wentao Jiao, the corresponding author of the study, underscores the transformative potential of PTEDMS: “Our integrated system marries solar power with advanced electrothermal and electrokinetic techniques to address the stubborn issue of organic soil pollutants without the environmental costs associated with fossil energy sources. The incorporation of machine learning empowers continuous, efficient, and site-tailored remediation, making PTEDMS a breakthrough in sustainable environmental management.”

The study detailing PTEDMS’s design and field validation was published on July 23, 2025, in the journal Eco-Environment & Health. Funded by the National Natural Science Foundation of China and the Strategic Priority Research Program of the Chinese Academy of Sciences, this work highlights the critical intersection of renewable energy, environmental science, and artificial intelligence in solving complex ecological problems.

In sum, PTEDMS encapsulates a visionary approach to soil remediation, offering a zero-carbon, intelligent, and adaptable solution for the environmental challenges of today and tomorrow. Its design principles and operational successes pave the way for a new era of eco-friendly technologies that can be tailored to various contamination contexts worldwide, promising healthier ecosystems and communities through sustainable innovation.

Subject of Research: Not applicable

Article Title: Photovoltaic-driven thermo-electro dual module sustainable decontamination in soil

News Publication Date: 23-Jul-2025

References:
DOI: 10.1016/j.eehl.2025.100173

Image Credits: Eco-Environment & Health

Keywords: Research methods

As the UK government aims for a significant increase in solar energy capacity to reach net zero carbon emissions by 2050, there has been considerable debate regarding land use conflicts, particularly concerning high-quality agricultural land. The traditional model of ground-mounted solar parks has been contentious, as critics voice their concerns about the threat to food production and the visual impact on rural landscapes. Agrivoltaics offers a solution that can mitigate these issues, providing a practical means to enhance energy generation while preserving essential farmland.

One of the most remarkable findings of the University of Sheffield study is the sheer coverage potential of agrivoltaics technology. Research suggests that if implemented effectively, this innovative methodology could not only fulfill the UK’s solar energy targets but do so up to four times over. By strategically deploying solar panels across regions with favorable conditions—such as Cambridgeshire, Essex, and Lincolnshire—the country could tap into a vast resource of renewable energy without the associated drawbacks of conventional solar farms. This high capacity demonstrates how agrivoltaics can fundamentally reshape energy production in the UK landscape.

The appeal of agrivoltaics extends beyond the realm of clean energy. Previous studies conducted in regions like Tanzania and Kenya illustrate that this technology doesn’t merely produce renewable electricity; it can significantly enhance agricultural productivity as well. Under the partial shade provided by solar panels, crops such as maize, Swiss chard, and beans exhibited improved growth rates and water conservation. By reducing evaporation and utilizing rainwater effectively, agrivoltaics emerges as a vital adaptation strategy in response to climate change pressures that threaten food security globally.

The researchers identified specific geographic zones in the UK that are particularly suited for the deployment of agrivoltaic systems. Factors such as land flatness, existing agricultural practices, grid connectivity, and optimal solar radiation levels were evaluated to determine the most effective locations. By concentrating efforts in these regions, stakeholders can ensure a greater likelihood of success and sustainability for agrivoltaic projects.

The vision articulated by Professor Sue Hartley, Vice-President for Research and Innovation at the University of Sheffield, underscores a crucial intersection between agricultural sustainability and renewable energy production. The urgency surrounding global food security, exacerbated by political unrest and climate-related risks, necessitates innovative solutions that do not favor one essential resource over another. Agrivoltaics presents an opportunity to utilize the same land for both food cultivation and clean energy generation, addressing criticisms directed at conventional solar farms.

In promoting the multifaceted use of land through agrivoltaics, the study advocates for a policy dialogue that encourages diverse land-use strategies. The research effectively bridges the energy-agriculture divide, calling for data-driven solutions aimed at reconciling these two critical sectors. The implications extend beyond environmental benefits; they touch upon socioeconomic factors, bolstering local economies through enhanced agricultural yields and energy independence.

Notably, the research identifies the need for further empirical studies within the UK context. While substantial research has been conducted in continental Europe, UK-specific data are scarce. Next steps involve field trials to evaluate the operational viability of agrivoltaic systems, testing various designs and crop combinations while gathering insights from local communities and stakeholders. Such endeavors could establish a framework for implementing agrivoltaics on a wider scale.

This initiative not only showcases the potential of agrivoltaics in fostering renewable energy resilience but also emphasizes its role in cultivating public engagement on energy matters. Communities often resist solar park developments due to fears over land loss. The research endeavors to shift that narrative, highlighting how compatible solar installations can coexist with agricultural endeavors, thus alleviating tensions and fostering acceptance within local populations.

As the pursuit of sustainability escalates, the urgency of addressing land use conflicts becomes paramount. Research and innovation in agrivoltaics exemplify a forward-thinking approach to resource management, balancing energy needs with agricultural imperatives. The integration of solar technology into farming practices opens new avenues for farmers, empowering them with tools to manage resources more efficiently.

With climate change prompting reevaluation of traditional land management practices, agrivoltaics emerges as a pioneering concept at the intersection of agriculture, technology, and energy. The UK stands at a crossroads, where embracing such innovations could position the nation as a leader in the global sustainability movement. The potential of agrivoltaics is not just limited to energy generation; it embodies a holistic approach to environmental stewardship and economic resilience.

The study issued by the University of Sheffield isn’t merely a call to action; it’s an invitation to rethink our relationship with land, food, and energy. By harnessing technological advancements to foster an integrated approach to farming and energy, the UK can set a precedent for other nations grappling with similar challenges. The future may well depend on the choices we make today regarding the sustainable coexistence of agricultural production and renewable energy.

Subject of Research: Agrivoltaics
Article Title: The spatial potential for agrivoltaics to address energy-agriculture land use conflicts in Great Britain
News Publication Date: [Publication date not provided]
Web References: [Web references not provided]
References: [References not provided]
Image Credits: [Image credits not provided]
Keywords: Agrivoltaics, solar energy, crop yields, food security, climate change, land use, renewable energy, energy-agriculture, United Kingdom, sustainable farming.