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Abstract

Electrochromic (EC) windows face trade-offs in cost, switching speed, color neutrality, and durability. We present solution-processed n-doped poly(benzodifurandione) (n-PBDF) as a robust organic conductor for black EC windows overcoming these limitations. Utilizing an engineered solvent ink and ultrasonic spray coating, we achieve uniform large-area n-PBDF deposition under ambient conditions without additives. n-PBDF EC electrodes show unprecedented weathering durability (maintaining performance under simultaneous exposure to light (including UV), heat, and humidity for >768 h), addressing a key barrier for organic EC materials. The electrodes exhibit deep black coloration with color neutrality, rapid switching (<2 s), and remarkable cycling stability (>20,000 cycles). Large-area EC devices demonstrate uniform switching performance, confirming scalable fabrication. Building energy simulations of the EC window reveal significant HVAC savings potential across diverse transitional climates. This work establishes n-PBDF as a scalable, high-performance alternative to conventional inorganic EC systems, advancing the viability of solution-processable smart windows for sustainable architecture.

Electrochromic materials are widely explored in energy-saving smart windows, yet combining fast switching, neutral black coloration, and robust long-term durability remains challenging. Here the authors report a solution processed n-doped poly(benzodifurandione) affording an electrochromic black window that overcomes these limitations.

Details

1009240
Business indexing term
Title
Robust fast-switching black electrochromic windows based on solution-processed n-doped transparent organic conductor
Author
Lee, Won-June 1   VIAFID ORCID Logo  ; Mehra, Palak 1 ; Thurston, Jonathan R. 2 ; Tian, Yanpei 3 ; Liu, Xiaojie 4 ; Samal, Sanket 1   VIAFID ORCID Logo  ; You, Liyan 1 ; Song, Inho 5   VIAFID ORCID Logo  ; Ruan, Xiulin 3   VIAFID ORCID Logo  ; Toney, Michael F. 6   VIAFID ORCID Logo  ; Mei, Jianguo 1   VIAFID ORCID Logo 

 James Tarpo Jr. and Margaret Tarpo Department of Chemistry, Purdue University, West Lafayette, IN, USA (ROR: https://ror.org/02dqehb95) (GRID: grid.169077.e) (ISNI: 0000 0004 1937 2197) 
 Department of Chemistry, University of Colorado, Boulder, CO, USA (ROR: https://ror.org/02ttsq026) (GRID: grid.266190.a) (ISNI: 0000 0000 9621 4564) 
 School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA (ROR: https://ror.org/02dqehb95) (GRID: grid.169077.e) (ISNI: 0000 0004 1937 2197) 
 James Tarpo Jr. and Margaret Tarpo Department of Chemistry, Purdue University, West Lafayette, IN, USA (ROR: https://ror.org/02dqehb95) (GRID: grid.169077.e) (ISNI: 0000 0004 1937 2197); School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA (ROR: https://ror.org/02dqehb95) (GRID: grid.169077.e) (ISNI: 0000 0004 1937 2197) 
 James Tarpo Jr. and Margaret Tarpo Department of Chemistry, Purdue University, West Lafayette, IN, USA (ROR: https://ror.org/02dqehb95) (GRID: grid.169077.e) (ISNI: 0000 0004 1937 2197); Department of Chemical Engineering, Chung-Ang University, Seoul, Republic of Korea (ROR: https://ror.org/01r024a98) (GRID: grid.254224.7) (ISNI: 0000 0001 0789 9563) 
 Department of Chemical and Biological Engineering, Materials Science and Engineering Program, Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, USA (ROR: https://ror.org/02ttsq026) (GRID: grid.266190.a) (ISNI: 0000 0000 9621 4564) 
Publication title
Volume
17
Issue
1
Pages
575
Number of pages
13
Publication year
2026
Publication date
2026
Section
Article
Publisher
Nature Publishing Group
Place of publication
London
Country of publication
United States
Publication subject
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
Document type
Journal Article
Publication history
 
 
Online publication date
2025-12-14
Milestone dates
2025-11-26 (Registration); 2025-07-12 (Received); 2025-11-26 (Accepted); 2026-01-15 (Version-Of-Record)
Publication history
 
 
   First posting date
14 Dec 2025
ProQuest document ID
3293538110
Document URL
https://www.proquest.com/scholarly-journals/robust-fast-switching-black-electrochromic/docview/3293538110/se-2?accountid=208611
Copyright
© The Author(s) 2025. This work is published under http://creativecommons.org/licenses/by-nc-nd/4.0/ (the "License"). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.
Last updated
2026-01-16
Database
ProQuest One Academic