Photochromism in Ruddlesden–Popper copper-based perovskites: a light-induced change of coordination number at the surface

Abstract

Ruddlesden-Popper organic-inorganic hybrid copper-based perovskites have been studied for decades owing to a variety of interesting properties, such as thermochromism and piezochromism, and the mechanisms behind these phenomena have been...

Detecting alcohol vapors using two-dimensional copper-based Ruddlesden–Popper perovskites

“…A possible explanation for this behavior is that the charge carrier blockade caused by the antiferrodistortive orbital ordering-a characteristic of the pristine material 31 -is removed by the structural change from an octahedral copper chloride structure to square-planar CuCl 4 2À ions upon UV exposure. 32 This would lead to a higher conductance, analogous to the findings of Arkenbout et al 31 For both the pristine and UV-converted material, our conductance varied from device to device. We attributed this to slight variations in perovskite film morphology due to the spin coating technique used to fabricate the layer, which could also affect the quality of the gold contacts.…”

“…After that, the sample holder was evacuated and refilled with ambient air. This resulted in a drop of the conductance over 30 minutes to 6.4 Â 10 À13 S. Considering that UV-converted (PEA) 2 CuCl 4 is not stable in air, 32 this degradation in conductance is not unexpected. After the air exposure, the sample was illuminated with UV light for 45 minutes in a nitrogen-filled glovebox.…”

“…31 Our recent publication on (PEA) 2 CuCl 4 demonstrated that this material exhibits photochromism, i.e., it changes from a yellow to a brown phase upon exposure to ultraviolet (UV) light. 32 During this process, the octahedral copper-chloride structure at the surface changes to isolated square-planar CuCl 4 2À ions, destroying the structural order in the inorganic xy-plane. In this work, we compare both phases of (PEA) 2 CuCl 4 , with the goal of using these materials for vapor sensing applications.…”

“…1(a) for the crystal structure of the pristine material] was based on the spin coating technique (the details are provided in the supplementary material), which leads to a strong parallel orientation of the inorganic planes with respect to the substrate. 32 This orientation is favorable for conduction in two-dimensional hybrid perovskites when a planar device geometry is used. 33 First, we compared the conductance of pristine and UV-converted (PEA) 2 CuCl 4 devices in nitrogen without any alcohol present.…”

Color-Stable and High-Efficiency Blue Perovskite Nanocrystal Light-Emitting Diodes via Monovalent Copper Ion Lowering Lead Defects

“…And the XPS spectrum reveals typical Cu + 2p signals (Figure 3d), effectively affirming the existence of Cu + in doped PNCs. 42 To be specific, the Cu 2p XPS spectrum of Cu + -doped CsPbClBr 2 PNCs presents the spin−orbital coupling of Cu 2p 1/2 Cu 2p 3/2 lines at 931.7 eV and 952.0 eV, respectively (Figure 3d, Table S1). 43 The 2p 3/2 peak in the Cu + -doped sample appeared at 931.7 eV, lower than Cu 2+ of 934.0 eV (Figure S4d), 42,44 which could be assigned to the Cu 2p signal of Cu + .…”