*Abstract: The spectral evolution of photoluminescence (PL) in   ultrafast timescales provides a straightforward route to investigate   photoexcitation processes. Various applications have been demonstrated many   areas in chemistry, physics, biology, and material science. Accessing the crucial   sub-picosecond timescale requires using nonlinear optical effects trigger by   femtosecond laser pulses. However, the conventional nonlinear optical gating   method, fluorescence up-conversion, suffers from narrow spectral bandwidth   due to phase matching condition, while the broadband method, optical Kerr   gating suffers from low sensitivity due to high background noise. From technical   point of view, it still demands a high-performance ultrafast PL method to simultaneously   satisfy the requirements of effectiveness, ultrafast time-resolution, high   sensitivity, and broad spectral bandwidth. Here, we perform a novel ultrafast   time-resolved PL spectroscopy system based on the transient grating PL   spectroscopy technique and advanced femtosecond light sources. This   combination enables us to achieve a high-performance ultrafast optical gate   driven by high pulse energy, high repetition rate, and ultrashort laser   pulses. This system can rapidly capture sub-picosecond emission dynamics from   UV to near-infrared region. We will use case studies in optoelectronic   materials as examples to highlight the capability and new applications of   this advanced optical characterization technique for material sciences.