Temperature-Dependent Transient Photocurrent Investigations for 2D, 3D, and Hybrid 2D/3D Tin Perovskite Films

Understanding the interplay between electronic and ionic dynamics in tin halide perovskites is critical for optimizing their photovoltaic performance and stability. Here, we combine temperature-dependent transient photocurrent (TPC) and photoluminescence (PL) measurements under a lateral bias in a coplanar-electrode geometry for a 2D Dion–Jacobson phase (B1: BDASnI4), a 3D phase (E1: FASnI3), and their physically paired 2D/3D hybrid (E1B1) phase. In B1, rapid carrier extraction (τrise ∼ 1 ms) and a pronounced PL red-shift (−0.8 meV/K) reflect strong electron–phonon coupling and minimal ionic screening. Arrhenius analysis of Iph reveals two activation energies, Ea ∼ 0.13 eV at low temperature T and a higher barrier of ∼1.4 eV above ∼320 K, indicating the emergence of deeply bound trap populations. The 3D E1 exhibits sluggish kinetics (τrise ∼ 90 ms), a +0.6 meV/K blue-shift, and three activation regimes (Ea ∼ 0.34, 0.50, and 0.70 eV), consistent with migrating iodide vacancies. The E1B1 hybrid film shows dual PL emissions and a trifurcated activation profile (Ea ∼ 0.24, 0.43, and 0.63 eV), capturing interfacial passivation at low T and trap-dominated ionic pinning at high T. By correlating spectral shifts with TPC-derived energetics, we demonstrate how dimensionality and interfacial chemistry together dictate exciton behavior, ionic mobility, and thermal response under device operational conditions.