Atomic force microscopy of S1, S3 and S4 host films

Raw atomic force microscopy height images (.nid) of thin films of the deep-blue TADF host materials S1, S3 and S4, the archived Gwyddion XYZ exports and statistics files, reference films of alpha-NPD and Alq3, and the numerical tables of the roughness, correlation-length and power-spectrum analysis. Methods: Instrument: Nanosurf FlexAFM, tapping (phase-contrast) mode, Dyn190Al cantilevers; the Central Research Facility (CRF), National Institute of Technology Karnataka (NITK), Surathkal. Images: 256 x 256 pixels, scan sizes 2-51 um. Sessions (folder dates): 5 Mar 2022; 3-5 May 2022 (glass and quartz, M1-M4 series); 15-16 Mar 2023; Jun 2024; Feb 2025. Substrate: glass or quartz where the file name records it (May 2022: -G/-Q; Mar 2023 exports: glass); otherwise "substrate-not-recorded". Exports: XYZ text exports and statistics files written by Gwyddion (extension .txt added in this record; the originals had none). Processing (processed/R6_AFM_*): plane levelling, row-median alignment, zero offset; Sa, Sq, skewness, kurtosis, autocorrelation length, power-spectral-density slope and fractal dimension with bootstrap intervals; quantities failing the quality rules are left empty (table set C lists the rejected values). legacy_AFM_summaries holds the 2022-2024 summary workbooks. Caveats: one 16 Mar 2023 image (S00001.nid) has no material label (MAT_UNRESOLVED); one 16 Mar 2023 export named S3_Glass_xyz sits in the S4 folder (LABEL_CONFLICT); 16-3-2023_TADF/S/S.nid is a JPEG with a .nid extension and is not included. Layout: per-material folders S1/, S3/ and S4/. Code names: DB4 = S1 (main batch); DBPYBPS = second, less pure S1 batch (flagged, never pooled); DDPYS/DOPYS = S3; DOPS = S4 (source file names resolved against HR-LCMS/NMR, 24 Oct 2026); code-name subfolders S1/S1_DB4, S1/S1_DBPYBPS, S3/S3_DDPYS, S4/S4_DOPS, processed/ (numerical tables) and REF_reference_materials/ where present. MANIFEST.csv gives the SHA-256, material, original code name, original path and acquisition date of every file; see README.md. Acknowledgements: Mr. Pradeep Hebbar (CRF, NITK) for the AFM measurements. Pranav, project student of the Optoelectronics Laboratory, for the alpha-NPD reference-film scans of 2022. Host materials S1, S3 and S4 were synthesised and supplied by the group of Prof. Jayathirtha Rao Vaidya, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad. M. Dash acknowledges an institutional research fellowship from NITK Surathkal.