Amorphous WO3 ･H2O films were fabricated via spin-coating of a WOCl4 solution at a low temperature of 80 °C, and the influence of gas atmosphere during film formation on electrochromic (EC) performances was systematically investigated. The films prepared under an Ar atmosphere exhibited a relatively porous morphology compared to those formed under air, which showed a more uniform and compact surface structure. These morphological differences significantly affected charge transport and electrochemical behavior. In particular, the films formed under air demonstrated enhanced electrical conductivity and faster ion transport due to the formation of a uniform surface morphology, leading to superior response speed and coloration efficiency. In contrast, films formed in the Ar atmosphere suppressed partial crystallization of WO3, thereby increasing the amorphous WO3 ･H2O fraction with abundant oxygen bonding sites that act as electrochemically active sites. This characteristic enabled a wider optical modulation during coloration. These results indicate that processing gas-atmospherecontrolled amorphous WO3 ･H2O films at low-temperature is an effective strategy for improving EC performance and expanding their applicability to flexible devices and energy-efficient smart window technologies.

Abstract
1. 서 론
2. 실험 방법
3. 결과 및 고찰
4. 결 론
Acknowledgement
References
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• 강성훈(강원대학교 신소재생명화학공학부 세라믹신소재공학전공) | Seong-Hoon Kang (Department of Advanced Materials and Biochemical Engineering, Kangwon National University, Gangneung 25457, Republic of Korea)
• 정지용(강원대학교 신소재생명화학공학부 세라믹신소재공학전공) | Ji Yong Jung (Department of Advanced Materials and Biochemical Engineering, Kangwon National University, Gangneung 25457, Republic of Korea)
• 구본율(강원대학교 신소재생명화학공학부 세라믹신소재공학전공) | Bon-Ryul Koo (Department of Advanced Materials and Biochemical Engineering, Kangwon National University, Gangneung 25457, Republic of Korea) Corresponding author