# Most-cited Engineering papers of 2020, with free PDFs

The 25 most-cited Engineering research papers published in 2020, ranked by citations in OpenAlex, with their original abstracts and free PDFs where available.

1. [Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and the Road Ahead](https://nerdi.pages.dev/paper/W3043220753) · 3,322 citations · Free PDF
2. [Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects](https://nerdi.pages.dev/paper/W3004850069) · 2,915 citations · Free PDF
3. [Digital Twin: Enabling Technologies, Challenges and Open Research](https://nerdi.pages.dev/paper/W2982936646) · 2,895 citations · Free PDF
4. [High-Efficiency Perovskite Solar Cells](https://nerdi.pages.dev/paper/W3045599769) · 2,827 citations
5. [A reflection on lithium-ion battery cathode chemistry](https://nerdi.pages.dev/paper/W3013252775) · 2,824 citations · Free PDF
6. [Deep Learning for 3D Point Clouds: A Survey](https://nerdi.pages.dev/paper/W3039448353) · 2,396 citations
7. [Characterising the Digital Twin: A systematic literature review](https://nerdi.pages.dev/paper/W3012041784) · 2,387 citations
8. [Guidelines and trends for next-generation rechargeable lithium and lithium-ion batteries](https://nerdi.pages.dev/paper/W3005657800) · 2,250 citations
9. [Toward 6G Networks: Use Cases and Technologies](https://nerdi.pages.dev/paper/W3011830499) · 2,233 citations · Free PDF
10. [A review of lithium-ion battery safety concerns: The issues, strategies, and testing standards](https://nerdi.pages.dev/paper/W3127891378) · 2,180 citations
11. [U2Fusion: A Unified Unsupervised Image Fusion Network](https://nerdi.pages.dev/paper/W3046194589) · 2,131 citations
12. [Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction](https://nerdi.pages.dev/paper/W3112882062) · 2,109 citations
13. [Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts](https://nerdi.pages.dev/paper/W3110989801) · 2,047 citations · Free PDF
14. [Sustainable Recycling Technology for Li-Ion Batteries and Beyond: Challenges and Future Prospects](https://nerdi.pages.dev/paper/W3003658253) · 2,038 citations
15. [Joint Radar and Communication Design: Applications, State-of-the-Art, and the Road Ahead](https://nerdi.pages.dev/paper/W3006143078) · 2,014 citations · Free PDF
16. [Single‐Junction Organic Photovoltaic Cells with Approaching 18% Efficiency](https://nerdi.pages.dev/paper/W3013363765) · 1,965 citations
17. [Roadmap for advanced aqueous batteries: From design of materials to applications](https://nerdi.pages.dev/paper/W3027710877) · 1,965 citations
18. [Digital Twin: Values, Challenges and Enablers From a Modeling Perspective](https://nerdi.pages.dev/paper/W3003667836) · 1,904 citations · Free PDF
19. [A Spatial-Temporal Attention-Based Method and a New Dataset for Remote Sensing Image Change Detection](https://nerdi.pages.dev/paper/W3027225766) · 1,902 citations · Free PDF
20. [A Survey of Autonomous Driving: Common Practices and Emerging Technologies](https://nerdi.pages.dev/paper/W2953303875) · 1,883 citations · Free PDF
21. [6G Wireless Communication Systems: Applications, Requirements, Technologies, Challenges, and Research Directions](https://nerdi.pages.dev/paper/W2976566279) · 1,866 citations · Free PDF
22. [Principles of Geotechnical Engineering](https://nerdi.pages.dev/paper/W1577484784) · 1,822 citations
23. [Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry](https://nerdi.pages.dev/paper/W3045563350) · 1,814 citations
24. [Consensus statement for stability assessment and reporting for perovskite photovoltaics based on ISOS procedures](https://nerdi.pages.dev/paper/W3002058265) · 1,809 citations · Free PDF
25. [What should 6G be?](https://nerdi.pages.dev/paper/W3002159761) · 1,727 citations · Free PDF

Canonical page: https://nerdi.pages.dev/papers/engineering/most-cited-2020