• • Intermediate FA content yields balanced n=2 to n=5 quantum-well phases, enabling ultrafast carrier transfer (<0.31 ps) and suppressed nonradiative recombination, which is critical for efficient optical gain in quasi-2D perovskites.
• • Optimized films achieve a net modal gain of 1041 cm−1 and a gain lifetime of 129 ps, surpassing typical solution-processed counterparts and demonstrating viability for high-performance lasing applications.
• • Cavity-free random lasing threshold is reduced to below 5 μJ/cm2 at room temperature, a significant improvement for practical laser devices requiring low pump energies.
• • Speckle contrast as low as 0.011 is achieved, enabling speckle-free imaging with enhanced contrast-to-noise ratios across all spatial frequencies, which is essential for high-quality imaging systems.