Reduction of Hysteresis in Hybrid Perovskite Transistors by Solvent-Controlled Growth

The effect of crystallization process speed on the morphology of solution-processed methyl ammonium lead iodide (MAPbI₃) thin films is investigated. Crystallization speed is controlled by varying the number of annealing steps, temperature, and resting time between steps. The resting period allows solvent-controlled growth (SCG) in which crystallization progresses slowly via an intermediate phase-during which solvents slowly evaporate away from the films. SCG results in fewer residues, fewer pinholes, and larger grain sizes. Consequently, thin-film transistors with SCG MAPbI₃ exhibit smaller hysteresis in their current-voltage characteristics than those without, demonstrating the benefits of SCG toward hysteresis-free perovskite devices.