Extending excited-state of sensitizer that absorbs visible photon and produces charge separation is of importance for a photoelectrochemical biofuel cell (PEBFC). In the present work, the dependence of series of porphyrins functionalized at beta-positions as sensitizers' structures on their excited-state are analyzed with the density functional theory and time-dependent density functional theory. The calculated results expect that the radiative lifetime decreases in the order of haematoporphyrin > protoporphyrin IX > H-2-mesoporphyrin IX. The designed PEBFCs with the above porphyrins as sensitizers are assembled, in which the photocurrent action spectra testifies that the order of the radiative lifetime is consistent with that of the incident photon-to-collected electron conversion efficiency (IPCE) value based on the series of porphyrins. All the experimental characteristics show that the porphyrin with ethanol group (-CIOH-CH3) at beta-positions can enhance the photovoltaic performance of the PEBFC as expected. (C) 2013 Published by Elsevier B.V.