Kim Ga Hye, Kim Hyeon-Beom, Lee Hyungseok, Cho Jae-Hyeok, Ryu Jun, Kang Dong-Won, Chung In, Jang Hyejin, Ahn Kyunghan, Kim Myung-Gil
School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Department of Materials Science and Engineering and Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, Republic of Korea.
Small. 2024 Nov;20(48):e2403133. doi: 10.1002/smll.202403133. Epub 2024 Sep 2.
Due to its small hole-effective mass, flexibility, and transparency, copper iodide (CuI) has emerged as a promising p-type alternative to the predominantly used n-type metal oxide semiconductors. However, the lack of effective doping methods hinders the utility of CuI in various applications. Sulfur (S)-doping through liquid iodination is previously reported to significantly enhance electrical conductivity up to 511 S cm. In this paper, the underlying doping mechanism with various S-dopants is explored, and suggested a method for controlling electrical conductivity, which is important to various applications, especially thermoelectric (TE) materials. Subsequently, electric and TE properties are systematically controlled by adjusting the carrier concentration from 3.0 × 10 to 4.5 × 10 cm, and accurately measured thermal conductivity with respect to carrier concentration and film thickness. Sulfur-doped CuI (CuI:S) thin films exhibited a maximum power factor of 5.76 µW cm K at a carrier concentration of 1.3 × 10 cm, and a TE figure of merit (ZT) of 0.25. Furthermore, a transparent and flexible TE power generator is developed, with an impressive output power density of 43 nW cm at a temperature differential of 30 K. Mechanical durability tests validated the potential of CuI:S films in transparent and flexible TE applications.
由于碘化铜（CuI）具有小孔有效质量、柔韧性和透明性，它已成为一种有前景的p型半导体，可替代主要使用的n型金属氧化物半导体。然而，缺乏有效的掺杂方法阻碍了CuI在各种应用中的实用性。此前有报道称，通过液体碘化进行硫（S）掺杂可显著提高电导率，最高可达511 S/cm。本文探讨了各种S掺杂剂的潜在掺杂机制，并提出了一种控制电导率的方法，这对各种应用，尤其是热电（TE）材料非常重要。随后，通过将载流子浓度从3.0×10调整到4.5×10 cm，系统地控制了电学和TE性能，并精确测量了热导率与载流子浓度和薄膜厚度的关系。硫掺杂的CuI（CuI:S）薄膜在载流子浓度为1.3×10 cm时表现出最大功率因数5.76 μW/cm K，热电优值（ZT）为0.25。此外，还开发了一种透明且灵活的TE发电机，在30 K的温差下具有令人印象深刻的43 nW/cm的输出功率密度。机械耐久性测试验证了CuI:S薄膜在透明和灵活TE应用中的潜力。
