Surface photovoltage (SPV), transient photovoltage (TPV), photoluminescence (PL) and time-resolved PL (TRPL) all characterize carriers in semiconductors. Choosing between them, or assembling them, depends on what each actually observes, and the four answers are quite different.
SPV: net charge separation, carriers moving apart and building a potential, a direct view of separation behavior. TPV: how long the separated state survives after excitation. PL: radiative recombination, photons emitted when electrons and holes meet again, strongest where recombination is radiative rather than reactive. TRPL: the lifetime of that radiative recombination, decomposed in time.
Use SPV/TPV when the question is separation and its persistence, the regime of photocatalysis and photoelectrochemistry. Use PL/TRPL when the question is electronic structure quality, defect-mediated recombination and junction effects, the regime of optoelectronic material development. In photocatalysis, PL tells you how fast charges are dying; SPV tells you how well they separated before dying.
PL is blind to non-radiative recombination, which dominates in many photocatalysts, so a dark PL sample is not necessarily a charge-starved sample. SPV is blind to carriers that recombine before contributing to surface potential. Neither substitutes for activity data; both predict it.
Strong material studies use the methods as a chain: absorption (UV-Vis), separation (SPV), survival (TPV), recombination character (PL/TRPL), and finally activity. Each method validates the interpretation of the next, and the chain closes the argument.
Perfectlight provides the separation-and-survival links: SPV/TPV systems, plus complete mechanism research solutions.
