xTB-Based High-Throughput Screening of TADF Emitters: 747-Molecule Benchmark

We validate semiempirical sTDA-xTB and sTD-DFT-xTB methods for high-throughput screening of thermally activated delayed fluorescence (TADF) emitters using 747 experimentally characterized molecules─the largest such benchmark to date. Our framework achieves >99% computational cost reduction versus TD-DFT while maintaining strong internal consistency (Pearson <i>r</i> ≈ 0.82) and reasonable agreement with 312 experimental singlet-triplet gaps (MAE ≈ 0.17 eV). Large-scale analysis statistically validates key design principles: D-A-D architectures outperform other motifs, and optimal torsional angles of 50^°-90^° maximize TADF efficiency, while PCA confirms a low-dimensional property space. This work establishes xTB methods as cost-effective tools for accelerating TADF discovery.