Phenanthro[110,9,8-cdefg]carbazole-Thiophene, Donor-Donor Copolymer for Narrow Band Green-Selective Organic Photodiode

A new donor donor copolymer consisting of phenanthro[1,10,9,8-cdefg]carbazole and thiophene unit (PP-Th) was synthesized for narrow band green-selective organic photodiode application. Thanks to well-defined intramolecular conjugation and inhibited intermolecular interaction of PP-Th compared to its donor- acceptor type analogues, PP-Th revealed narrow band green-selective absorption peak at 510 nm with low full width at half-maximum value of 98 nm. In addition, deep ionization energy of PP-Th, as confirmed by photophysical analyses, made it less susceptible to oxidational degradation. Green-selective organic photodiodes (OPDs) were fabricated utilizing PP-Th as a green absorbing donor material and ZnO as a nonabsorbing acceptor material. The optimized OPD rendered a very low dark current of 2 nA cm(-2) and a high detectivity of 1.42 x 10(12) Jones with narrow band green-selectivity. Moreover, PP-Th enabled OPD with a high 3-dB bandwidth of 3.1 kHz and a high linear dynamic range of 84.9 dB. Furthermore, the responsivity of the OPD could be maintained for more than 30 days under atmospheric condition, revealing excellent stability of PP-Th.