Accurately Assess the Photoexcited Carrier Transport Properties of Perovskite Thin Films under ∼1 Sun in Frequency Domain by Photocarrier Radiometry Measurement

Carrier dynamics critically influence the optoelectronic performance of perovskite solar cells (PSCs). Accurate assessment and deep insight into carrier transport and recombination properties of perovskites are fundamentally imperative. In practical application scenarios, evaluation under 1-sun illumination, typical low-injection condition, is essential as it simulates actual operation. However, this poses a challenge for transient techniques, which may not be fully appropriate since the requirement for strong pulses to achieve adequate signal-to-noise ratios. In this work, we introduce and validate photocarrier radiometry (PCR) technology for perovskite carrier dynamics investigation in frequency-domain. Notably, the nonlinear effect observed in perovskite leads to a rapid decrease in carrier lifetime under high light intensity (79 ns at 100 sun) while remaining stable (∼200 ns) in the low intensity linear region (<1 sun), resulting from a shift in the dominant recombination mechanism from trap-assisted nonradiative to band-to-band radiative recombination. With high signal-to-noise ratio of PCR, we achieved dynamics measurements under 1-sun intensity─a near-linear state that parameters remain stable. Based on this, we evaluated the poly(methyl methacrylate) (PMMA) passivation effect by extracting the surface recombination velocity, which shown a significant reduction from ∼250 to ∼30 cm s–1. This work emphasizes the research of light intensity-dependent carrier dynamics, helps comprehend the relationship between device performance and carrier dynamics, and provides a method for the industrial assessment of perovskite film.