Low-voltage perovskite light-emitting transistors: a novel approach utilizing solution-processed high-k inorganic dielectrics for full-color emission†

Perovskite materials have garnered significant attention in recent years due to their exceptional optoelectronic properties, making them promising candidates for a wide range of electroluminescent applications. Among these, perovskite light-emitting transistors (PeLETs), which integrate perovskite-based light-emitting layers, have been extensively studied. However, a key challenge remains: most reported PeLETs require high operating voltages ranging from tens to hundreds of volts, limiting their practical use in applications such as active-matrix displays. In this study, we introduce a high-k dielectric layer of HfO_x in the fabrication of perovskite thin-film light-emitting transistors, achieving a significant reduction in operating voltage. The device, employing an optimized structure, operates at a low source–drain voltage of just 4 V. To further enhance device performance, PEA⁺ cations are incorporated to modify CsPbI₃/Br₃, and by adjusting the halogen composition, red, green, and blue PeLETs are realized. The maximum mobility values for the red, green, and blue devices are 0.74 cm² V⁻¹ s⁻¹, 0.67 cm² V⁻¹ s⁻¹, and 0.66 cm² V⁻¹ s⁻¹, respectively. Notably, we report the first-ever blue-emitting perovskite thin-film light-emitting transistor, providing critical insights into the low-voltage operation of PeLETs and their potential for application in future full-color display technologies.