The rough surface of the ZnO film hinders the device from making uniform photovoltaic cells. In this work, we illustrated the power conversion efficiency of 6.02% and open-circuit voltage of 12.55 mA/cm2 by optimizing the ZnO film through the application of 0.6 M of precursor concentration. Figure 4 J – V curves of the devices. ITO/PEDOT:PSS/ICBA:P3HT/Al and ITO/ZnO(0.4, 0.6, and BAY 80-6946 order 0.8 M precursor)/PEDOT:PSS/ICBA:P3HT/Al. Table 1 Performance characteristics of the photovoltaic devices Device Short-circuit current (mA/cm2) Open-circuit voltage (V) Fill factor Power conversion efficiency (%) Pristine 8.9757 0.8286 0.6124 4.5545 0.2 M precursor 9.9191 0.8306 0.6226 5.1293 0.4 M precursor 11.4798 0.8318 0.6057 5.7841 0.6 M precursor 12.5483

0.8360 0.5976 6.0196 0.8 M Precursor 7.8613 0.7150 0.5636 3.1679 Devices: ITO/PEDOT:PSS/ICBA:P3HT/Al and ITO/ZnO (0.4, 0.6, 0.8 M precursor)/PEDOT:PSS/CBA:P3HT/Al. External quantum efficiency External quantum efficiency (EQE) characterization of cells with the structure of ITO/ZnO film/PEDOT:PSS/P3HT:ICBA (1:1 wt.%)/Al is shown in Figure 5. When applying ZnO film with 0.2 M

precursor concentration, there was no difference compared to the pristine device. There were three peaks around 340, 415, and 520 nm. For the pristine device and the device with 0.2 M precursor concentration, the maximum external quantum efficiency of 14.0% and 16.4% at 520 nm was achieved, while the PCE of the devices was 4.55% and 5.13%, Anlotinib supplier respectively. In the device containing more than 0.4 and 0.6 M precursor concentration, large improvement in EQE was observed. However, a decrease of nearly half of the whole area was observed in the device including ZnO film DihydrotestosteroneDHT in vitro prepared from 0.8 M of precursor concentration.

It GNA12 is attributed to the high surface roughness of the ZnO film. It could disrupt the fabrication of uniform photovoltaic devices. For the ZnO films prepared from 0.4 and 0.6 M of precursor concentration, a small blueshift of 415 to 400 nm and 520 to 510 nm in the photo response of the nanostructured device was observed. This blueshift in the EQE of the devices could be due to increased crystallizability of the ZnO fiber films. The ZnO film-incorporated device prepared from 0.6 M of precursor concentration achieved a maximum external quantum efficiency of 39.3% at 510 nm. Figure 5 External quantum efficiency of the devices as precursor concentration increases 0.4 to 0.8 M. Conclusions In this work, we synthesized ZnO fibrous nanostructure by sol-gel process with various precursor concentrations. We have investigated the performance characteristics of organic photovoltaic cells using nanostructured ZnO film as a hole-transporting layer. ZnO film-based photovoltaic cells were focused on the dependency of Zn2+ precursor concentration with morphology. By adding ZnO fiber film, the conductivity and carrier mobility of the device were improved. As the precursor concentration increased, ZnO (002) orientation was observed.