In this letter we report the three-photon absorption-induced upconversion fluorescence emission and the three-photon absorption cross-section of two fluorene derivatives with D-π-D (9,9-didecyl-2,7-bis-(N,N-diphenylamino) fluorene) and D-π-A ((7-benzothiazol-2-yl-9,9-didecylfluoren-2-yl) diphenylamine) structural motifs. The three-photon absorption cross-section of the D-π-D analog (σ3′=82×10 -78 cm6s2photon-2) is 2.2 times greater than that of its D-π-A counterpart (σ3 ′=37×10-78 cm6s 2photon-2), showing that symmetric charge transfer enhances 3PA. The three-photon-excitation of these two compounds in hexane solution (9.8×10-3 M) was accomplished with a tunable OPG pumped by picosecond laser pulses. The three-photon absorption coefficients were measured using an open aperture Z-scan technique.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry