Composition change-driven texturing and doping in solution-processed SnSe thermoelectric thin films

• Published in: Nature communications Vol. 10; no. 1; pp. 864 - 10
• Main Authors: Heo, Seung Hwae, Jo, Seungki, Kim, Hyo Seok, Choi, Garam, Song, Jae Yong, Kang, Jun-Yun, Park, No-Jin, Ban, Hyeong Woo, Kim, Fredrick, Jeong, Hyewon, Jung, Jaemin, Jang, Jaeyoung, Lee, Won Bo, Shin, Hosun, Son, Jae Sung
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20.02.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 639/301/299/2736; 639/4077/4107; 639/925/357/551; Composition; Crystals; Doping; Humanities and Social Sciences; multidisciplinary; Polycrystals; Power factor; Purification; Science; Science (multidisciplinary); Single crystals; Texturing; Thermoelectricity; Thin films
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-08883-x

The discovery of SnSe single crystals with record high thermoelectric efficiency along the b -axis has led to the search for ways to synthesize polycrystalline SnSe with similar efficiencies. However, due to weak texturing and difficulties in doping, such high thermoelectric efficiencies have not been realized in polycrystals or thin films. Here, we show that highly textured and hole doped SnSe thin films with thermoelectric power factors at the single crystal level can be prepared by solution process. Purification step in the synthetic process produced a SnSe-based chalcogenidometallate precursor, which decomposes to form the SnSe 2 phase. We show that the strong textures of the thin films in the b–c plane originate from the transition of two dimensional SnSe 2 to SnSe. This composition change-driven transition offers wide control over composition and doping of the thin films. Our optimum SnSe thin films exhibit a thermoelectric power factor of 4.27 μW cm −1 K −2 . Despite significant efforts to improve the thermoelectric properties of polycrystalline SnSe, precise control of texturing and doping is a challenge. Here, the authors report hole doped and highly textured SnSe thin films prepared by low cost, scalable solution processing.