【公開日：2025.06.10】【最終更新日：2025.05.08】

課題データ / Project Data

課題番号 / Project Issue Number

24NM5087

利用課題名 / Title

Tunable structural order/disorder functional ceramics: a novel prospect of sulfides-based materials

利用した実施機関 / Support Institute

物質・材料研究機構 / NIMS

機関外・機関内の利用 / External or Internal Use

内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)

技術領域 / Technology Area

【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-

【重要技術領域 / Important Technology Area】（主 / Main）マテリアルの高度循環のための技術/Advanced materials recycling technologies（副 / Sub）-

キーワード / Keywords

セラミックスデバイス/Ceramic device,光学材料・素子/ Optical materials,熱電材料・素子/ Thermoelectric materials,X線回折/ X-ray diffraction

利用者と利用形態 / User and Support Type

利用者名（課題申請者）/ User Name (Project Applicant)

ブールジュ セドリック ミシェル クロード(BOURGES Cedric Michel Claude)

所属名 / Affiliation

物質・材料研究機構

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

利用形態 / Support Type

（主 / Main）機器利用/Equipment Utilization（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

NM-212：卓上型粉末回折計_Cu_ASC_NC1

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

I synthesized and densified bulk Cu₂ZnSnS₄, Cu_2-xS and ZnS compound in order to realize performant thermoelectric or transparent materials. Different synthesis approach and composition has been investigated and required structural analysis after each process step.

実験 / Experimental

The samples were characterized by long scan (10min-1h) in order to perform phase recognition in the minimal range of 10-100 degree. The phases in presences were confirmed before and after thermal treatment in all series. The doping level was also confirmed through the Rietveld refinement which providing the lattice parameter and/or atomic distribution of each sample.

結果と考察 / Results and Discussion

For the Cu₂ZnSnS₄-CZTS, I investigated and developed a novel synthesis approach that combines a short time of mechanical alloying (3h) of the pure metal element (Cu, Zn, Sn, and S) with a reactive sintering step by Spark Plasma Sintering to be able to produce a pure CZTS with control stoichiometry which corresponds to the most important point in order to develop an understanding of the process influence later. Based on this reliable approach for producing the CTZS material, the “calibration” series in composition and off-stoichiometry have been realized. The XRD has been systematically perform at the end of the full process to confirm the single-phase purity with a Rietveld refinement (Fig. 1). After this important step, the sample can be included in a database to develop the process optimization by machine learning.Finally, for the ZnS, I engaged an ultra-short process with a few hours of MA process(1-3h) followed by a short SPS process (less than 1h), previously developed on the commercial powder, and successfully reached the formation of the ZnS structure with a reasonable transmittance in the visible range. Then, as a proof of concept, the Cu-doped and Al-doped samples have been synthesized to screen the possibility of turning the ceramics conductive. The preliminary study reveals that it’s possible to obtain the right structure of the ZnS in both cases and I show that the doping contributes to reducing or canceling the formation of the hexagonal ZnS phase (Fig. 3). It is worthy to inform that the hexagonal ZnS phase negatively affects the transparent properties of ZnS which is currently the main challenge I face for the undoped sample. Therefore, the discovery that the dopants play a role in the single-phase formation of the ZnS is a major insight and will be interpreted and used in the future development of this ceramic.

図・表・数式 / Figures, Tables and Equations

Fig1. XRD pattern of the CZTS sample synthesized by MA/SPS, R_Bragg, and R_F correspond to the reliability factor of the Rietveld analysis and attest to the high purity of the phase.

Fig 2. XRD pattern of the digenite synthesis of the sealed tube (SS), mechanical alloying (MA), and hot injection (HI) a) before and b) after Spark Plasma Sintering Densification

Fig. 3. XRD pattern of ZnS optimal sample.

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

成果発表・成果利用 / Publication and Patents

論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)

1. Cédric Bourgès, Process optimization on kesterite-based ceramics for enhancing their thermoelectric performances assisted by active machine learning approach: A tool for metal-sulfide ceramics development, Acta Materialia, 281, 120342(2024).
   DOI: 10.1016/j.actamat.2024.120342
   
2. Cédric Bourgès, Heat capacity and structural transition effect in polycrystalline kesterite, Journal of Materials Chemistry C, 12, 16309-16313(2024).
   DOI: 10.1039/D4TC02105C
   
3. Xinyuan Wang, Process influence on thermoelectric performance of digenite (Cu1.8S) and its underlined thermal instability, Ceramics International, 51, 10443-10452(2025).
   DOI: 10.1016/j.ceramint.2024.12.477
   

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

1. Sept. 2024: Oral: « ALMLBO Pipeline Approach Apply to Materials Process and Composition Optimization for Energy-Saving Application » at the « IWAMSN2024» in Da Nang, Vietnam

特許 / Patents

特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件