On the contrary, in this middle region, the signal from Ti and O elements increase rapidly and then exhibit a fairly flat upon further increase of scanning distance. The clear distinct difference in the spatial

profiles from CIS and TiO2 is well consistent with well-defined structures and SEM images, confirming that there is a CIS layer on the top of TiO2 film, and the pores of TiO2 film have been filled by CIS nanoparticles. Figure 5 Cross-sectional see more SEM images of samples with CIS film prepared from (a) 0.03 M or (b,c) 0.1 M InCl 3 . Figure 6 EDS line scan analysis along the red line indicated in the SEM image (Figure 5 b). Furthermore, the phase and optical property of TiO2/CIS film sample with CIS prepared with 0.1 M InCl3 were investigated. Figure  7 shows the typical XRD

pattern. Besides those existing peaks from SnO2 (2θ: 26.6°, 33.8°, 37.8°, 51.7°, 61.8°, 65.8°; from FTO substrate) and TiO2 film (2θ: 25.3°, 37.8°, 48.0°), the diffraction peaks at 27.8°, 46.5°, and 55.1° are assigned to (112), (204)/(220), and (312)/(116) planes of CIS, respectively, which are consistent with our previous study [4] and the data obtained from JCPDS card no. 85-1575. This fact confirms that CIS layer is well crystallized and has chalcopyrite structure. Furthermore, the optical absorption of TiO2/CIS film was measured using a UV-vis Selleckchem Pevonedistat spectrometer, as shown in Figure  8 (line A). This spectrum presents strong adsorption within a broad range between 400 and 800 nm, which is the characteristic absorption of CIS and consistent with our previous study [4]. Figure 7 XRD pattern of TiO 2 /CIS film sample, where CIS CHIR-99021 datasheet film was prepared from 0.1 M InCl 3 . Figure 8 UV-vis/NIR absorption spectra. TiO2/CIS (a) and TiO2/CIS/P3HT (b) film samples. The fourth step was to in turn deposit P3HT and

PEDOT:PSS layer on FTO/compact-TiO2/nanoporous-TiO2/CIS film by the spin-coating process (Figure  1 (step D)). After the coating of P3HT, the photoabsorption of the film increases obviously in the range of 400 to 700 nm, as shown in Figure  8 (line B), since P3HT solution exhibits a wide and strong absorption with peak at about 445 nm [43]. This fact also indicates the efficient deposition of P3HT in/on TiO2/CIS film. It should be noted that there are plenty of macro-pores among superstructures, nanopores inside CIS flower-shaped superstructures, and nanopores in TiO2 film due to the Selleck Tariquidar insufficient filling. The hierarchical combination of smaller nanopores and larger macro-pores can be considered as transport paths [41]. It can be expected that P3HT solution can easily enter the deep layer of FTO/compact-TiO2/nanoporous-TiO2/CIS film through the transport paths, when they are coated onto its surface during the spin-coating process.