High-performance hysteresis-free perovskite transistors through anion engineering

Abstract

Despite the impressive development of metal halide perovskites in diverse optoelectronics, progress on high-performance transistors employing state-of-the-art perovskite channels has been limited owing to ion migration and large organic spacer isolation. Herein, we report high-performance and hysteresis-free p-channel perovskite thin-film transistors (TFTs) based on methylammonium tin iodide (MASnI3) and rationalise the effects of halide (I/Br/Cl) anion engineering on crystallinity enhancement and vacancy suppression, realising a high hole mobility of 20 cm2 V−1 s−1, current on/off ratio exceeding 107, and threshold voltage of 0 V with high operational stability and reproducibility. We reveal ion migration has a negligible contribution to the hysteresis of Sn-based perovskite TFTs; instead, minority carrier trapping is the primary cause. Finally, we integrate the perovskite TFTs with commercialised n-channel indium gallium zinc oxide TFTs on a single chip to construct high-gain complementary inverters, facilitating the development of halide perovskite semiconductors for printable electronics and circuits.

Antimony fluoride (SbF3): A potent hole suppressor for tin(II)‐halide perovskite devices

“…This can be attributed to unintentional I − doping of SbI 3 . The iodine vacancy (donor state) is easily formed in the halide perovskite owing to its low formation energy and weak bonding 35,36 . The extra I − addition in the precursor passivates the iodine vacancy, which induces p‐doping and compensates for the Sb 3+ electron doping effect.…”

“…The iodine vacancy (donor state) is easily formed in the halide perovskite owing to its low formation energy and weak bonding. 35,36 The extra I À addition in the precursor passivates the iodine vacancy, which induces p-doping and compensates for the Sb 3+ electron doping effect. Owing to the large ionic radius difference between I À (220 pm) and F À (133 pm), F À has been demonstrated to be impractical for iodine vacancy occupation or I À substitution.…”

Molecular design for perovskite solar cells

“…For example, the AX and BX 2 precursors in the precursor solution are essentially in the molecular form at the starting point, and non‐stoichiometric precursors are viable to generate improved perovskite film quality; the unreacted PbI 2 is suggested to improve the perovskite film crystallinity 69‐71 and facilitate the electron transfer to the neighboring TiO 2 layer. Compositionally engineering the methylammonium precursor is common, 72,73 and switching to the chloride‐based methylammonium precursor solution can help the crystallization of the triple A‐cation perovskite film 74,75 …”