Modulation of photocarrier dynamics in indoline dye-modified TiO ₂ nanorod array/P3HT hybrid solar cell with 4- tert -butylpridine

The influences of the 4-tert-butylpridine (TBP) treatment prior to the P3HT infiltration on the performance of the D149-modified TiO₂ nanorod (NR) array/P3HT solar cell are investigated in this work. The efficiency of the D149-modified TiO₂ NR array/P3HT hybrid solar cell is enhanced from 1.58% to 1.83% through the TBP treatment for a proper duration. With the cell characteristic of both D149 and P3HT contributing to the photocurrent, the short-circuit current density of the hybrid solar cell is enhanced by 30% with the TBP treatment. Absorption spectra indicate desorption of D149 molecules from TiO₂ NRs with TBP treatment, suggesting that part of the TiO ₂ NR surface is passive by TBP molecules. Time-resolved photoluminescence and electrochemical impedance spectroscopy are employed to investigate the photocarrier dynamics of the hybrids. The results indicate that the photocarrier dynamics are modulated to decrease both the photocarrier generation rate and the recombination rate at the interface of D149-modified TiO₂ NR and P3HT when TBP molecules are adsorbed on TiO₂ NRs after the treatment. The enrichment of the photocurrent in the D149-modified TiO₂ NR array/P3HT hybrid solar cell is, therefore, achievable with an appropriate ratio of D149 and TBP coadsorbed on the TiO₂ NR array.