Tuning Charge Transport in Perovskite Nanoparticle Assemblies through Temporal Surface Engineering

Thin-film transistors (TFTs) based on lead halide perovskite nanoparticles (LHP NPs), where the NPs serve as the semiconducting channel, hold great promise for optoelectronic applications, where high carrier mobility and stability are essential. In this work, we introduce temporal surface engineering as an effective strategy to optimize the performance of CsPbBr3 perovskite NPs. By systematically tuning the duration of the heat treatment following methyl acetate (MeOAc) treatment, we achieve a 2–3 orders of magnitude increase in steady-state current and field-effect mobility, with the resulting devices remaining relatively stable. FTIR spectroscopy confirms gradual removal of long-chain organic ligands, while KPFM measurements reveal a steady increase in work function with treatment time, indicating Fermi level shifts consistent with enhanced hole injection. Structural analysis shows that prolonged treatment induces Ostwald ripening and stabilizes the cubic phase, improving film uniformity and robustness. Prolonged PL lifetimes confirm defect passivation, and temperature-dependent transport studies attribute mobility enhancement to increased electronic coupling and extended localization lengths, consistent with 3D Mott’s variable range hopping. This work highlights temporal surface engineering as a scalable route to improve both charge transport and operational stability in perovskite-based TFTs and related optoelectronic devices.