Femtosecond Transient Absorption Spectra and Dynamics of Carrier Relaxation of Tin Perovskites in the Absence and Presence of Additives

Abstract

The effects of additives SnF2 (10%) and EDAI2 (1%) on the dynamics of carrier relaxation of formamidinium tin triiodide (FASnI3) perovskite were studied using femtosecond transient absorption spectra (TAS) with excitation at 600 and 870 nm. The TAS were analyzed according to a parallel sequential kinetic model with a global fit through singular-value decomposition. For excitation at 600 nm, two relaxation paths were found: one involved hot and cold carriers in the bulk state undergoing shallow bulk-defect-mediated charge recombination; the other involved trap carriers in the surface state undergoing deep surface-defect-mediated charge recombination. For excitation at 870 nm, only cold carriers were subjected to the bulk-state relaxation channel. Our spectral results indicate significant effects of the additives on retarding charge recombination in both bulk and surface states as well as decreasing the bandgap renormalization energy, the bandwidth of the photobleaching (PB) band, and the Stokes shift between the PB and photoluminescence bands, explaining how the device performance of FASnI3 solar cells became enhanced in the presence of SnF2 and EDAI2.

Highly efficient green InP-based quantum dot light-emitting diodes regulated by inner alloyed shell component

“…As shown in Fig. 3c , the TA spectra of InP/ZnSe 0.7 S 0.3 /ZnS exhibited a slight shift of peaks for both PA and PB, which confirmed the restrain of the interface defects and featured layered quantum-well structure 41 , 45 – 47 . While the inner shell was tuned to InP/ZnSe/ZnS QDs as shown in Fig.…”

“…While the inner shell was tuned to InP/ZnSe/ZnS QDs as shown in Fig. 3d , the peaks showed apparently bleach at PB, indicating the weakened passivation ability of the traps at InP core and ZnSe interface 45 – 47 . What’s more, the dynamic spectra of these samples were characterized as shown in Fig.…”

Slot‐Die‐Coated Organic Solar Cells Optimized through Multistep Crystallization Kinetics

“…PM6 and ITIC both contribute to the signals from 600 to 700 nm. Thus, singular-value decomposition (SVD) [37,38] is applied to analyze the TA spectra (Figure 3e). The SVD2 represents the ITIC exciton's signal and SVD1 represents the polaron's signal of PM6.…”

Controlling the Crystallization Kinetics of Lead‐Free Tin Halide Perovskites for High Performance Green Photovoltaics

“…The research community has recognized that tin halide perovskites are promising materials for environment friendly leadfree photovoltaic devices. With much effort, the maximum PCE of tin halide PSCs has been pushed to over 14%, [94,[159][160][161][162] but it is still considerably lower than the theoretical efficiency of 33.4% for the photovoltaic material with 1.4 eV bandgap. This situation prompted us to contribute this review article aiming to inspire an in-depth understanding and precise control of the crystallization process of tin halide perovskite films for further improving the efficiency and stability of tin halide PSCs.…”