(ii) spatially separated triplet-pair state (SSP); and (iii) spin decoherence (SD) processes. Recent spectroscopic studies revealed that the singlet excited state (S 1 ) is converted into an intermediate state, triplet pair state (T 1 T 1 ), within hundreds of femtosecond . Moreover, two triplet states T 1 is formed with a relatively slow process via a spin decoherent process . In the literature, there is a persistent debate of nature of the intermediates in the PSF process and its underlying physics .