. It is worth mentioning that the molar absorption coefficient (3 ¼39,066 M
1cm
1
)
ofSDD4 is almost twice as high as that of reference dye RD
(3 ¼19,628 M
1cm
1
), which indicates that the absorption ofSDD4
is enhanced and overlapped by the two DepeA light-harvesting
units in one molecule.