Tube-in-Furnace Grown Scalable Perovskite Single-Crystal Thin Films with Ultrahigh Optical Gain and Polarization Sensitivity

), which represents one of the highest values reported in halide lead perovskite thin films. We further explore the polarization-sensitive photoluminescence (PL), absorption, and photoresponsivity of the thin films, demonstrating their unique optoelectronic behavior under varying polarization states. Our scalable, simple, and cost-effective process for producing single-crystal thin films has potential for next-generation optoelectronic devices, including perovskite lasers, LEDs, and photodetectors (PDs), with a large cavity, enabling larger-scale crystal growth for practical and widespread use.