Switchable optical and dielectric properties of TBAPh2MnBr4: Unraveling phase transition effects in low-dimensional perovskite-…

Lead-free low-dimensional perovskite-like structures have attracted significant interest as a step toward environmentally friendly perovskite-based optoelectronics. While some of these materials have demonstrated white light photoluminescence, a comprehensive understanding of their unique photo-electric coupling is still evolving. This study focuses on the optical and dielectric properties of a lead-free low-dimensional perovskite-like compound, TBAPh2MnBr4. The compound exhibits switchable optical and dielectric properties. To comprehend the phase transition behavior, we conducted differential scanning calorimetry measurements, revealing a first-order transition with pronounced thermal hysteresis and entropy changes characteristic of order-disorder transitions at 352 K (311 K). Dielectric measurements show a step-like anomaly with thermal hysteresis, confirming the first-order nature of the phase transition. Further exploration of the compound's photoluminescence properties revealed a broad green emission and a significant shift in intensity near the phase transition temperature, indicative of switchable optical properties. These findings highlight the potential of TBAPh2MnBr4 as a multifunctional material, making it a promising candidate for optoelectronic applications.