Figure 25.

Sn²⁺‐free perovskite FET. a) The crystal lattice structure of vacancy‐ordered double perovskite Cs₂SnI₆. b) TFT structure and corresponding cross‐sectional TEM image. c) X‐ray diffraction peak patterns of Cs₂SnI₆ as a function of the CsI:SnI₄ ratio in the precursor solution. d) Transfer characteristics of Cs₂SnI₆ TFT with various ratios of Mn²⁺ doping. e) Summary of electron mobility µ _e and I _on/I _off of TFTs. f) Normalized µ _FE of Sn²⁺‐based (PEA)₂SnI₄ TFT and Sn(IV)‐based Cs₂SnI₆ TFTs as a function of ambient air exposure time. g) Schematic diagram of CMOS inverter with combined p‐channel (PEA)₂SnI₄ TFT and n‐channel Mn²⁺‐doped Cs₂SnI₆ TFT. Corresponding h) voltage transfer and i) gain voltage curves at different V _DDs. a–i) Reproduced with permission.^{[ 92 ]} Copyright 2022, Cell Press.