The kinetic study of the photoinduced electron transfer process between aqua soluble perylenequnone derivative (13-SO3Na-DDHA) and colloidal semiconductors(CdS)

According to the principle of electron transfer dynamics mu < 0 (mu = E-S*/ (S+) - E-CB) in heterogeneous systems, the thermodynamics of electron trans fer from 13 - SO3Na - DDHA* (sodium salt of 14 - dehydroxy - 15 - deacetyl - hypocrellin A - 13 - sulfonate, an aqua soluble perylenequnone derivative ) to the conductor band of CdS sol in our CdS - (13 - SO3Na - DDHA) complex is allowed. 13 - SO3Na - DDHA adsorbed strongly on colloidal CdS with an a pparent association constant K-app of 1480 (mol/L)(-1) determined by fluore scence quenching method. Using TEMPO (2,2, 6, 6 - tetramethyl - 1 - piperdi nyloxy), a stable free radical, as the electron acceptor, the kinetics of t he photoinduced reduction reaction taking place on the surface of CdS collo idal particles was studied by the electron spin resonance method. The react ion order of TEMPO is zero and different from that of spin elimination reac tion in a homogeneous systems such as HA (hyporcrellin A). By comparing rat e constants, it is discovered that the CdS - (13 - SO2Na - DDHA) complex sy stem is 82 times more efficient than CdS sol in photoreduction of TEMPO und er the same visible light condition. The results show that the aqua soluble photosensitizer (13 - SO3Na - DDHA) has efficient photosensitization actio n on CdS colloidal semiconductor. It suggests that 13 - SO3Na - DDHA can he used as the efficient sensitizer of colloidal semiconductor in the applica tion of solar energy.