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

Abstract

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.

Defects in lead halide perovskite light-emitting diodes under electric field: from behavior to passivation strategies

“…Mativenga et al varied the resting time between these steps to enable solvent-controlled growth of MAPbI 3 thin films, yielding films with fewer residues, pinholes, and defects. 230 During the intermediate resting period, gradual solvent evaporation mitigated the rapid evaporation of solvents in the second step, effectively decelerating the entire crystallization process and resulting in devices with reduced defects and enhanced performance. Furthermore, the residual stress in the lattice exhibited a linear dependence on the annealing temperature, with higher temperatures resulting in increased stress levels in the film.…”