[1]. Sharper diffraction peaks are observed from the diffraction peaks of the PFO-DBT nanorods which indicate a semi-crystalline polymer. The PFO-DBT nanorod is confined inside the cavity of the template which then alters its molecular KU-60019 mw structure to a more aligned and elongated chain segment [11, 12]. The crystallite size of the PFO-DBT nanorods can be verified using the Scherrer equation as shown in Equation 1: (1) Figure 6 X-ray diffraction (XRD) patterns of template and PFO-DBT nanorods. The nanorods were grown

inside the template of different spin coating rates. From this equation, L is the mean crystallite size, K is the Scherrer constant with value 0.94, λ = 1.542 Å is the X-ray source wavelength, and β is the FWHM value. The PFO-DBT crystallite size is

around 20 to 30 nm. The PFO-DBT nanorods that have been deposited inside the porous template find more exhibited a semi-crystalline polymer with enhanced polymer chain due to the restricted intrusion into the cavities. Optical properties The absorption spectra of the PFO-DBT nanorod bundles with different spin coating rates are shown in Figure 7a. These spectra portray two absorption peaks mainly assigned to PFO segments (short wavelength) and DBT units (long wavelength). The absorption band of the PFO-DBT thin film has been reported to locate at 388 nm (short wavelength) and 555 nm (long wavelength) [2, 4]. Enhancement on the PFO-DBT’s optical properties can be realized with the low spin coating rate of 100 rpm. With the denser distribution of the PFO-DBT nanorod bundles, the absorption band at short NSC23766 wavelength and long wavelength is shifted to 408 and 577 nm, respectively. The absorption peak of the PFO-DBT nanorod bundles at short wavelength is redshifted at approximately 20 nm compared to that of the PFO-DBT thin film reported by Wang et al. [4]. The peak at Masitinib (AB1010) short wavelength corresponds to the transition of π- π* at fluorene units [4], which indicates that the strong π-π* transition

has occurred via the denser PFO-DBT nanorod bundles. At the long wavelength, the PFO-DBT nanorod bundles that were obtained at the low spin coating rate of 100 rpm were recorded to have an absorption band at 577 nm which was assigned for the DBT units [3]. The maximum peak of 577 nm yields the higher intensity which indicates that the absorption of dioctylfluorene moieties is assisted by the thiophene [18]. The redshift of the absorption peaks is correlated with the morphological distribution of PFO-DBT nanorod bundles. It can be postulated that the highly dense nanorod bundles with close pack arrangement would give a better conjugation length and chain segment. Such improvement in conjugation length can be utilized to enhance the photovoltaic properties of polymeric solar cell. The morphological distribution of the PFO-DBT nanorod bundles has a significant contribution to their optical properties.