Scanning Photocurrent Microscopy in Single Crystal Multidimensional Hybrid Lead Bromide Perovskites

Abstract

We investigated solution-grown single crystals of multidimensional 2D–3D hybrid lead bromide perovskites using spatially resolved photocurrent and photoluminescence. Scanning photocurrent microscopy (SPCM) measurements where the electrodes consisted of a dip probe contact and a back contact. The crystals revealed significant differences between 3D and multidimensional 2D–3D perovskites under biased detection, not only in terms of photocarrier decay length values but also in the spatial dynamics across the crystal. In general, the photocurrent maps indicate that the closer the border proximity, the shorter the effective decay length, thus suggesting a determinant role of the border recombination centers in monocrystalline samples. In this case, multidimensional 2D–3D perovskites exhibited a simple fitting model consisting of a single exponential, while 3D perovskites demonstrated two distinct charge carrier migration dynamics within the crystal: fast and slow. Although the first one matches that of the 2D–3D perovskite, the long decay of the 3D sample exhibits a value two orders of magnitude larger. This difference could be attributed to the presence of interlayer screening and a larger exciton binding energy of the multidimensional 2D–3D perovskites with respect to their 3D counterparts.

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“…The photocurrent maps indicated that the effective decay length cuts near the border, indicating the importance of border recombination centres in monocrystalline samples [36]. The multidimensional 2D-3D perovskites showed a single exponential fitting model, while the 3D perovskites confirmed a fast and slow charge carrier migration dynamic inside the crystal [36].…”

“…The study by Segura-Sanchis et al [ 36 ] focused on scanning photocurrent microscopy (SEM) in single-crystal multidimensional hybrid lead bromide perovskites. Their composition played an important role in their optoelectronic properties, mainly the effect on the photogenerated transport charges along the microcrystals [ 36 ].…”

“…The study by Segura-Sanchis et al [ 36 ] focused on scanning photocurrent microscopy (SEM) in single-crystal multidimensional hybrid lead bromide perovskites. Their composition played an important role in their optoelectronic properties, mainly the effect on the photogenerated transport charges along the microcrystals [ 36 ]. Noteworthy changes among multidimensional perovskite crystals regarding the photocarrier decay length values and spatial dynamics across the crystal were also noted [ 36 ].…”

“…Their composition played an important role in their optoelectronic properties, mainly the effect on the photogenerated transport charges along the microcrystals [ 36 ]. Noteworthy changes among multidimensional perovskite crystals regarding the photocarrier decay length values and spatial dynamics across the crystal were also noted [ 36 ]. The photocurrent maps indicated that the effective decay length cuts near the border, indicating the importance of border recombination centres in monocrystalline samples [ 36 ].…”

“…Noteworthy changes among multidimensional perovskite crystals regarding the photocarrier decay length values and spatial dynamics across the crystal were also noted [ 36 ]. The photocurrent maps indicated that the effective decay length cuts near the border, indicating the importance of border recombination centres in monocrystalline samples [ 36 ]. The multidimensional 2D–3D perovskites showed a single exponential fitting model, while the 3D perovskites confirmed a fast and slow charge carrier migration dynamic inside the crystal [ 36 ].…”