| 초록 |
In this presentation, we develop four different dyes that consist of Donor (triphenyl amine) – benzothiadiazole (BT) - Spacer (benzene, thiophene, toluene, and hexylthiophene) - Acceptor (cyanoacetic acid) to investigate the back electron transfer according to the change of dihedral angle between BT and acceptor. This is because the change of dihedral angle is one of key parameter to control the back electron transfer. Density function theory (DFT) calculations of these dyes provide further insight into molecular geometry, especially dihedral angle and the impact of spacer unit on the back electron transfer and photovoltaic performance. In addition, we find that the back electron transfer can be dramatically reduced under thin TiO2 film (1.6 ㎛) compared with thick TiO2 film (6 ㎛). As a result, organic dye with thiophene spacer unit reaches 7.3% of PCE under 1.6 ㎛ TiO2 film while 5.4% of PCE under 6 ㎛ TiO2 film. |
