***************************************************************** Experimental ***************************************************************** mC-PSC fabrication - TEC 7 fluorine doped tin oxide (FTO) glass substrates were etched using a Rofin Nd:YVO4 laser (532 nm) at a speed of 150 nm·s^-1. Substrates were cleaned with isopropanol (IPA, Sigma-Aldrich) and deionised (DI) water and further treated with O2 plasma. A compact layer of TiO2 was deposited via spray pyrolysis at 300°C from a solution 1:9 of titanium di-isopropoxide bis(acetylacetonate) (Sigma) in IPA. 30 NRD TiO2 paste (Dyesol) 2:3 terpineol (Sigma) by weight was screen printed onto the c-TiO2 and cells were sintered at 550°C for 30 min. ZrO2 paste (Solaronix) was screen printed on top of TiO2 and sintered at 400°C for 30 min. A carbon paste (Gwent Electronic Materials) was screen printed on top of the ZrO2 and sintered at 400°C for 30 min. 1M of PbBr2 (98%, Sigma-Aldrich) was dissolved in N,Ndimethylformamide (DMF, anhydrous, Sigma-Aldrich) at 70°C and 6 µl dropped onto the active area of each cell while substrates were heated at 70°C and further sintered at 70°C for 30 min. The cell was then immersed in CsBr (99.999%, Sigma-Aldrich) solution in methanol (17 mg·ml^-1 kept at 50°C in a vertical staining jar). After 30 min immersion, the sample was annealed at 150°C for 30 min. Devices were further post-annealed at different temperatures ranging between 100°C and 400°C for 30 min. C-PSC fabrication - FTO glass TEC 7 (Sigma-Aldrich) was etched with zinc powder and HCl. It was then cleaned in 2vol% Hellmanex solution in water, followed by DI water, acetone (VWR), IPA (VWR) and ethanol (VWR) before being treated with UV-Ozone cleaning. A compact TiO2 layer was deposited by spray pyrolysis, using a hand held atomiser to spray 20 mM solution of titanium diisopropoxide bis(acetylacetonate) (75wt%, Sigma-aldrich) in IPA onto the substrates held at 500°C. Substrates were then sintered at this temperature for 10 minutes. PbBr2 solution was spin coated on top of the substrates held at 70°C at 2500 rpm for 30 s and each cell was further sintered at 70°C for 30 min. The cell was then immersed in the CsBr solution kept at 50°C in a vertical staining jar for 30 min before being annealed at 150°C for 30 min. A carbon layer was deposited as top contact by doctor blade the carbon paste on top of the CsPbBr3 film. Devices were further post-annealed at different temperatures ranging between 100°C and 400°C for 30 min. ***************************************************************** Characterisation ***************************************************************** AFM - This contains the data from the atomic force microscopy, using Nanosurf easyscan 2 FlexAFM. The data are in .nid files, which can be read by Gwyddion (EPS and PNG format of the images are also uploaded). The files use the naming convention [sample]_[magnification].nid. JVcurves - This contains the data from the JV scans, using Keithley 2601A potentiostat, under 1 Sun intensity and AM 1.5. The data are in .csv files. Column 1: Voltage [V], Column 2: Current [A]. There are five subfolders: - C-PSC_BoxPlot contains files of JV scans of cells with planar architecture C-PSC. These are the cells used to plot box plots for statistical analysis of reproducibility. The files use the naming convention [sample].csv - C-PSC_JVtemp contains files of JV scans of cells with planar architecture C-PSC. In this experiment the post-annealing temperature was varied. The files use the naming convention [sample]_[Annealing_temperature].csv - mC-PSC_BoxPlot contains files of JV scans of cells with planar architecture mC-PSC. These are the cells used to plot box plots for statistical analysis of reproducibility. The files use the naming convention [sample].csv - mC-PSC_JVtemp contains files of JV scans of cells with planar architecture mC-PSC. In this experiment the post-annealing temperature was varied. The files use the naming convention [sample]_[Annealing_temperature].csv XRD - This contains the data with XRD patterns, using Bruker Advance D8 X-ray diffractometer with a Cu Ka source. IP583 , IP584 , IP585 , IP586 . The data are in .xlsx files. Column 1: 2theta [deg], Column 2: intensity [counts]. UV-Vis - This contains the data with UV-Vis spectra, using Perkin-Elmer Lambda 750S UV/Vis spectrometer, from 900 nm to 300 nm. IP480 and IP481 and IP482 and IP483 (R stands for R% spectrum and T stands for T% spectrum) SEM - This contains the data from the scanning electron microscope, JEOL SEM6480LV scanning electron microscope (SEM) (20 kV acceleration voltage and a magnification of 5000). Images are in .tif files, and specifications of images are in the text file. Impedance - This folder contains the impedance data obtained using Modulab. Each sample was scanned from 1×106 Hz to 0.5 Hz at seven different illumination intenisties ranging between 1.47×1015 and 1.47×1017 cm^2·s^-1. A single wavelength light with lambda = 465 nm was used. Impedance data were fitted by using ZView software (Scribner Associates). Data are in .xlsx files where the naming convention is [sample]_[architecture][Annealing_temperature].xlsx. File Fit_EIS_CsPbBr3 contais the fitting od each Nyquist plot. EQE - This folder cotains EQE data obtained by scanning the wavelength of imcoming light from 300 to 600 nm. The file JV_curves_cells contain the correspondent JV curves measured before testing EQE. XPS - This folder contain a xlsx file with the spectra obtained with the correspondent fitting for XPS data. XPS was carried out on a Kratos Axis Supra (Kratos Analytical, Manchester) instrument with samples connected to ground. Step size and pass energy used are 0.1 eV and 20 eV respectively. XPS data were analysed using CasaXPS and the Kratos sensitivity factor library.