Chonnam National University Breakthrough in Solar Cell Efficiency with New Germanium Oxide Layer
In the pursuit of renewable energy sources, solar power has emerged as a leading option due to its abundant availability and scalability. Recent advancements have turned the spotlight on thin-film solar cell technologies, which boast lower production costs and greater applicability in flexible electronics compared to traditional crystalline silicon cells. Yet, challenges have persisted, particularly in harnessing the full potential of tin monosulfide (SnS) solar cells. A team of researchers from Chonnam National University, led by Professor Jaeyeong Heo and Dr. Rahul Kumar Yadav, has taken significant strides in overcoming these limitations through a novel design.
Their compelling research, published on September 19, 2025, in the journal Small, details the incorporation of an extremely thin, 7-nanometer layer of germanium oxide (GeOx) to improve performance and device stability in SnS solar cells. SnS, known for being an affordable and non-toxic material, aligns with global sustainability goals. However, despite its ideal theoretical characteristics for sunlight absorption, conventional SnS solar cells have struggled with real-world efficiency. The primary issue has been attributed to defects at the rear-contact interface of the cells, where SnS connects to the metal electrode. This interface has been plagued by structural imperfections, chemical reactions, and atomic movement that impede effective charge collection.
Fortunately, the innovative GeOx interlayer addresses these issues proficiently. By employing a straightforward method that relies on the natural oxidation of a thin germanium film during vapor transport deposition, the researchers successfully created a scalable and reliable interface improvement. Professor Heo stated, "This layer, despite its nanoscale thickness, simultaneously mitigates long-standing challenges. It reduces harmful deep-level defects, inhibits undesirable sodium diffusion, and prevents the creation of resistive molybdenum disulfide compounds during high-temperature processing."
With these improvements, the quality of the SnS absorber has been significantly enhanced, leading to larger grain sizes, improved charge transport, and decreased electrical losses. Impressively, power conversion efficiency surged from a mere 3.71% in conventional devices to 4.81%, marking one of the highest efficiencies recorded for SnS solar cells fabricated by vapor deposition techniques.
The implications of this research extend beyond solar cells alone. Mastering the metal/semiconductor interface is crucial for the performance of various devices, including thin-film transistors, thermoelectric devices, and sensors. This breakthrough in interface engineering could catalyze advancements in numerous technologies, improving contact resistance in transistors and energy conversion efficiency in thermoelectric applications.
Professor Heo concluded, "We envision that our findings will pave the way for further research which is vital in advancing the development of not just solar cells but also other key technologies essential for a sustainable future."
For those seeking more details, the original paper titled "Optimized Rear-Interface Passivation of SnS Thin-Film Solar Cells Using a Controlled Germanium Oxide Interlayer for Enhanced Photovoltaic Performance" is available in the journal Small with DOI 10.1002/smll.202507626.
As research like this progresses, it underscores not only the innovative capabilities of academic institutions like Chonnam National University but also the potential for finding effective solutions to our global energy challenges. The journey toward more efficient and sustainable solar technologies continues, and the advancements in thin-film solar cells are promising indicators of progress in this vital area of renewable energy.
Their compelling research, published on September 19, 2025, in the journal Small, details the incorporation of an extremely thin, 7-nanometer layer of germanium oxide (GeOx) to improve performance and device stability in SnS solar cells. SnS, known for being an affordable and non-toxic material, aligns with global sustainability goals. However, despite its ideal theoretical characteristics for sunlight absorption, conventional SnS solar cells have struggled with real-world efficiency. The primary issue has been attributed to defects at the rear-contact interface of the cells, where SnS connects to the metal electrode. This interface has been plagued by structural imperfections, chemical reactions, and atomic movement that impede effective charge collection.
Fortunately, the innovative GeOx interlayer addresses these issues proficiently. By employing a straightforward method that relies on the natural oxidation of a thin germanium film during vapor transport deposition, the researchers successfully created a scalable and reliable interface improvement. Professor Heo stated, "This layer, despite its nanoscale thickness, simultaneously mitigates long-standing challenges. It reduces harmful deep-level defects, inhibits undesirable sodium diffusion, and prevents the creation of resistive molybdenum disulfide compounds during high-temperature processing."
With these improvements, the quality of the SnS absorber has been significantly enhanced, leading to larger grain sizes, improved charge transport, and decreased electrical losses. Impressively, power conversion efficiency surged from a mere 3.71% in conventional devices to 4.81%, marking one of the highest efficiencies recorded for SnS solar cells fabricated by vapor deposition techniques.
The implications of this research extend beyond solar cells alone. Mastering the metal/semiconductor interface is crucial for the performance of various devices, including thin-film transistors, thermoelectric devices, and sensors. This breakthrough in interface engineering could catalyze advancements in numerous technologies, improving contact resistance in transistors and energy conversion efficiency in thermoelectric applications.
Professor Heo concluded, "We envision that our findings will pave the way for further research which is vital in advancing the development of not just solar cells but also other key technologies essential for a sustainable future."
For those seeking more details, the original paper titled "Optimized Rear-Interface Passivation of SnS Thin-Film Solar Cells Using a Controlled Germanium Oxide Interlayer for Enhanced Photovoltaic Performance" is available in the journal Small with DOI 10.1002/smll.202507626.
As research like this progresses, it underscores not only the innovative capabilities of academic institutions like Chonnam National University but also the potential for finding effective solutions to our global energy challenges. The journey toward more efficient and sustainable solar technologies continues, and the advancements in thin-film solar cells are promising indicators of progress in this vital area of renewable energy.
Topics Energy）
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