Wang Teng, Ha Jangwoo, Mo Taejoon, Heo Seung Hwae, Hwang Hyein, Han Hyunjin, Kim Cheol-Joo, Dickey Michael D, Jin Hyungyu, Son Jae Sung
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongsangbuk-do 37673, Republic of Korea.
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongsangbuk-do 37673, Republic of Korea.
ACS Appl Mater Interfaces. 2024 Oct 16;16(41):55751-55759. doi: 10.1021/acsami.4c11775. Epub 2024 Oct 1.
The widespread adoption of halide perovskites for application in thermoelectric devices, DC power generators, and lasers is hindered by their low charge carrier concentration. In particular, increasing their charge carrier concentration is considered the main challenge to serve as a promising room-temperature thermoelectric material. Efforts have been devoted to enhancing the charge carrier concentration by doping and composition engineering. However, the coupling between charge carrier concentration and mobility, along with the poor stability of these materials, impedes their development for thermoelectric applications. Herein, we demonstrate the successful increase in the charge carrier concentration of CsPbIBr by forming a heterojunction structure with CuS via a facile spin-coating method. The excellent band alignment between two materials combined with a charge-transfer mechanism realizes the modulation doping, resulting in 8 orders of magnitude increase in carrier concentration from 10 to 10 cm without detrimental effect on the carrier mobility of CsPbIBr. The thermoelectric power factor of the heterostructured CsPbIBr reached 6.6 μW/m·K, which is 330 times higher than that of pristine CsPbIBr. Furthermore, these films showed higher humidity stability than the control films. This study offers a promising avenue for increasing the charge carrier concentration of halide perovskites, thereby enhancing their potential for various applications.
卤化物钙钛矿在热电设备、直流发电机和激光器中的广泛应用受到其低载流子浓度的阻碍。特别是，提高其载流子浓度被认为是成为有前景的室温热电材料的主要挑战。人们致力于通过掺杂和成分工程来提高载流子浓度。然而，载流子浓度与迁移率之间的耦合，以及这些材料稳定性较差，阻碍了它们在热电应用中的发展。在此，我们通过一种简便的旋涂方法与硫化铜形成异质结结构，成功提高了溴碘化铯铅（CsPbIBr）的载流子浓度。两种材料之间优异的能带排列与电荷转移机制相结合实现了调制掺杂，使载流子浓度从10 增加到10 ，提高了8个数量级，而对溴碘化铯铅的载流子迁移率没有不利影响。异质结构的溴碘化铯铅的热电功率因子达到6.6 μW/m·K，比原始的溴碘化铯铅高330倍。此外，这些薄膜显示出比对照薄膜更高的湿度稳定性。这项研究为提高卤化物钙钛矿的载流子浓度提供了一条有前景的途径，从而增强了它们在各种应用中的潜力。 （原文中“10 to 10 cm”表述有误，推测可能是“10¹⁹ to 10²⁷ cm⁻³”之类的，这里按原文翻译了）
