fig4

Figure 4. Characteristics depending on the pre-deposited layer before perovskite deposition. (A) PL decay curves with different vacuum-deposited hole transport layers; (B) current density and luminance data with varied transport layers; (C) current efficiency and EQE depending on the hole transport layer^[86]. Copyright 2019 John Wiley & Sons; (D and E) transient absorption spectra with or without an 18-crown-6 layer^[87]. Copyright 2022 Elsevier; (F) XRD patterns as a function of TOABr concentration pre-deposited before CsPbBr₃ deposition; (G) illustration of CsPbBr₃ crystal evolution with TOABr treatment^[88]. Copyright 2023 American Chemical Society; (H) UV-vis and PL spectra with TAPC or CzSi as charge transport layers, and (I) PL decay curves of CsPbBr₃ deposited on two different charge transport layers^[89]. Copyright 2023 John Wiley & Sons. PL: Photoluminescence; EQE: external quantum efficiency; XRD: X-ray diffraction; UV-vis: ultraviolet-visible spectroscopy; TOABr: tetraoctylammonium bromide; TAPC: 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane; CzSi: 9,9’-spirobifluorene-based carbazole derivative.