To see the details, Figure  3b shows the regional enlargement image of the CdS/TNTs at a scale bar of 100 nm. The #A-1210477 concentration randurls[1|1|,|CHEM1|]# CdS is well coated on the surface of the TNTs. The two types of inorganic nanostructure materials are compactly combined and dispersed in active layers uniformly. Figure 2 J – V characteristics of the device. The characteristics depend on the number of cycles of CdS deposition which is varied from 0 to 30 times under AM1.5G illumination of 100 mW/cm2. Table 1 Characteristic data of inverted polymer solar cells with different

cycles of CdS deposition on TNTs Cycles J SC (mA/cm2) V OC (V) FF (%) PCE (%) Rs (Ω) 0 9.84 0.56 48.12 2.63 32.6 10 11.29 0.56 47.63 3.01 33.5 20 13.31

0.59 48.81 3.52 30.2 30 12.28 0.60 41.13 3.04 44.9 selleck chemicals llc Figure 3 SEM surface image of a typical device. (a) The SEM surface image of a typical device; scale bar, 1 μm. (b) Regional enlargement image of the CdS/TNTs; scale bar, 100 nm. Figure  4 shows the UV-vis absorption spectra and the corresponding transmission spectra of the inverted PSCs with 20 cycles (device II) and without CdS(n)/TNTs (device I) between the wavelengths 350 and 700 nm. Obviously, after the CdS(n)/TNTs deposition, the absorption of the device II films appears around 400 to 650 nm. The absorbance of the spectra of the CdS(n)/TNTs films increases significantly not only in the UV region but also in the visible region, which is mainly due to the CdS(n)/TNT light absorption within the 350- to 500-nm excitation spectral range. It can be seen that the device II has a wider absorption range and a stronger absorption intensity than device I. CdS/TNTs are suitable for absorption enhancement of photovoltaic application. Figure Oxalosuccinic acid 4 Absorption for the two devices with and without the CdS( n )/TNTs. The inset is the corresponding transmission spectra of the two devices between the wavelength 350 and 700 nm. Figure  5 compares the incident photon-to-current collection efficiency (IPCE) spectrum of devices fabricated with and without the CdS(n)/TNT deposition in the active

layer. The IPCE is defined as the number of photo-generated charge carrier contributing to the photocurrent per incident photon. The conventional device (without the CdS(n)/TNTs) shows the typical spectral response of the P3HT:PCBM composites with a maximum IPCE of approximately 50% at 500 nm, consistent with the previous studies [29, 30]. For device II (with the CdS(n)/TNTs), the results demonstrate a substantial enhancement of approximately 10% in the IPCE less than the 500 nm excitation spectral range. The reason for this phenomenon may be due to the increased light absorption, which can be seen from Figure  4. On one hand, the increased light absorption due to the introduction of the CdS/TNT powder led to more generated electrons.