Enhancing Thermoelectric Power Factor of 2D Organometal Halide Perovskites by Suppressing 2D/3D Phase Separation. Issue 38 (30th July 2021)

• Record Type: Journal Article
• Authors: Yang, Seok Joo; Kim, Daegun; Choi, Jinhyeok; Kim, Seong Hyeon; Park, Kwanghee; Ryu, Sunmin; Cho, Kilwon
• Is Part Of: Advanced materials. Volume 33:Issue 38(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-30
• Subjects: chloride doping -- crystal orientation -- organometal halide perovskites -- phase separation -- quantum confinement effect -- Ruddlesden–Popper 2D perovskite -- thermoelectric; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202102797
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Organometal halide perovskites (OHPs) exhibit superior charge transport characteristics and ultralow thermal conductivities. However, thermoelectric (TE) applications of OHPs have been limited because of difficulties in controlling their carrier concentration, which is a key to optimizing their TE properties. Here, facile control of the carrier concentration in Sn‐based OHPs is achieved by developing 2D crystal structures. The 2D OHP crystals are laterally oriented using a mixed solvent, and the morphology and crystal structure of the coexisting 2D/3D hybrid structures are systematically controlled via doping with methylammonium chloride. The effective number n eff of inorganic octahedron layers in the 2D OHPs shows a strong positive correlation with the carrier concentration. Moreover, the 2D structure induces the quantum confinement effect, which enhances both the Seebeck coefficient and the electrical conductivity. A 2D OHP shows a high power factor of 111 µW m −1 K −2, which is an order of magnitude greater than the power factor of its 3D counterpart. Abstract : Reducing the dimension of the perovskite structure from 3D (MASnI3 ) to 2D [(PEA)2 (MA) n −1 Sn n I3 n +1 ( n = 1, 2, 3, 4)] enables a facile control of carrier concentration and induces the quantum confinement effect. Both the Seebeck coefficient and electrical conductivity increase at an optimum n, which results in a high thermoelectric power factor of 111 µW m −1 K −2 .