Amid the global push for clean energy transition, enhancing the photoelectric conversion efficiency of solar cells is a shared pursuit for both the scientific community and industry. Front-surface light-trapping technology serves as a critical method for improving battery performance by effectively reducing light reflection and extending the propagation path of light within the active layer. However, the fabrication of micro-nano structures with excellent light management capabilities has long relied heavily on costly silicon-based master templates, which has become a core bottleneck restricting their large-area commercial application.
Recently, a micro-nano manufacturing research team led by Prof. Jinyou Shao and Prof. Xiangming Li from the School of Mechanical Engineering at Xi'an Jiaotong University proposed a breakthrough solution. The team developed a novel flexible film featuring "multiply indented, hybrid 3D-nanobowls" and successfully established a large-scale, low-cost manufacturing process based on roll-to-roll (R2R) UV nanoimprint lithography. Maintaining high light transmittance while achieving astonishing ultra-high haze, this film provides a highly commercially viable new paradigm for front-surface light management in high-efficiency photovoltaic devices.
The research findings have been published in the renowned international academic journal Nano Research on April 27.
Breaking the High-Cost Barrier: Innovative Large-Area Template Fabrication
"How to manufacture large-area, high-quality nanoimprint templates at a low cost was the primary challenge we needed to overcome in this research," stated Prof. Jinyou Shao, the corresponding author of the paper. In traditional processes, creating master templates for complex 3D micro-nano structures often relies on expensive electron-beam lithography or photolithography.
To bypass this barrier, the research team took an alternative route by ingeniously utilizing the metal replacement reaction between aluminum (Al) and zinc (Zn) ions. This bottom-up chemical approach is not only cost-effective but also enables the spontaneous formation of core templates with complex geometries on large-area substrates, thoroughly paving the way for subsequent continuous R2R imprint production.
Structure Dictates Performance: 98% Ultra-High Haze and Multiply Indented Light-Trapping Mechanism
Following the mass production process breakthrough, the "hybrid 3D-nanobowl" structure designed by the team demonstrated remarkable optical performance. Unlike traditional single micro-pillar or micro-hole structures, the surface of this film is covered with multiply indented morphologies.
Prof. Xiangming Li pointed out: "This complex 3D nanobowl structure acts like an 'optical maze.' When incident light strikes the film surface, the multiply indented geometric edges and curved surfaces trigger intense refraction and multi-level scattering." Test data showed that this unique design allows the light-trapping film to maintain an excellent transmittance of 87% while its transmission haze soars to an exceptional 98%. This means light entering the cell is vastly scattered, substantially prolonging the residence time and propagation path of photons in the active layer, thereby significantly improving the light absorption efficiency of solar cells.
Broad Prospects from the Laboratory to Industrialization
This research achieves not only cost reduction and efficiency enhancement in micro-nano manufacturing but also new heights in optical performance. The excellent light-trapping effect, superb mechanical flexibility, and a process route fully compatible with R2R large-scale manufacturing endow this 3D nanobowl film with enormous application potential in perovskite solar cells, organic photovoltaic devices, and even flexible organic light-emitting diodes (OLEDs).
"Our goal is to make high-end light management technology truly practical," Prof. Shao added. "In the future, based on this low-cost R2R imprinting technology, we expect to customize micro-nano films with specific optical responses tailored to different optoelectronic device requirements, further driving the upgrading of the clean energy and optoelectronic display industries."
The authors of this paper include Jingchen Zhang, Congming Li, Zhangjian Li, Zhebo Ren, Xiangming Li, Ye Tang, Guifang Liu, Xinkai Zhu, Yangfan Qiu, Hongmiao Tian, Liang Wang, and Jinyou Shao from the School of Mechanical Engineering at Xi'an Jiaotong University.
This research was fully funded and supported by the National Natural Science Foundation of China (Nos. 52025065，52322513 and 52350349)
DOI Link:
https://doi.org/10.26599/NR.2026.94908395
About the Authors
Prof. Jinyou Shao, Professor and Ph.D. Advisor — Prof. Shao currently serves as the Vice President of Xi'an Jiaotong University and is a recipient of the National Science Fund for Distinguished Young Scholars. He has published over 160 SCI-indexed papers, including more than 80 papers as the first or corresponding author in prestigious international journals such as Nature Communications, Advanced Materials, and ACS Nano. His research has garnered over 3,100 independent SCI citations. Notably, several of his first or corresponding author publications have been featured as cover highlights in leading journals, including Advanced Materials, Advanced Functional Materials, Small, Nanoscale, and IEEE Nanotechnology. Furthermore, his works have been selected as featured or hot papers by the Institute of Physics (IOP), the American Chemical Society (ACS), and the Royal Society of Chemistry (RSC).
Prof. Xiangming Li, Professor and Ph.D. Advisor — Prof. Li is recognized as a National Leading Talent and is a recipient of the National Science Fund for Excellent Young Scholars. He serves as the Chief Young Scientist of the National Key Research and Development Program and was selected for the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology (CAST). Furthermore, he is a Silver Award laureate of the Hiwin Doctoral Dissertation Award in Mechanical Engineering. Specializing in micro/nano-structure manufacturing technologies, Prof. Li has published over 40 high-impact papers in top-tier journals such as Nature Communications and Advanced Materials, and holds more than 20 granted patents.
Jingchen Zhang, Ph.D. Candidate — Mr. Zhang is a Ph.D. candidate at the School of Mechanical Engineering, Xi'an Jiaotong University. His primary research focuses on the morphology and property control of nanoimprint templates and their applications. To date, he has published 3 SCI/EI-indexed papers and holds 1 granted invention patent.
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
