In order to assess the potential of the microwave-assisted LBZA synthesis process for practical ZnO applications, we fabricated DSCs using the ZnO NSs produced by air annealing the LBZA NSs at
400°C in air to replace the traditional TiO2 NP scaffold. Figure 7a shows the current voltage characteristics of a DSC under one sun illumination. The open circuit voltage, short circuit current density and fill factor were 0.67 V, 5.38 mA/cm2 and 35.6%, respectively. The quantum efficiency (incident photon to charge carrier efficiency) as a function of wavelength is shown on Figure 7b. The characteristic dye absorption peaks can be seen at 410 and 525 nm, as well as the ZnO band edge absorption at 370 nm. The overall efficiency was 1.3%, better Selleckchem C646 than some previously reported ZnO nanowire DSCs [21] and compares well cells made with very high aspect ratio ZnO NWs (1.5%) [22] but still lower than cells based on hierarchical ZnO, where the high surface-to-volume ratio led to efficiencies of 2.63% [23]. It should be noted that the thickness of the ZnO NSs film could not be controlled accurately in this initial experiment, resulting in varying degree of dye loading. In the future, we look to improve the efficiency by optimizing the thickness and exploring different dyes. Figure 7 Performance of a 1-cm 2 DSC fabricated with ZnO NSs. (a) Current–voltage curve of the DSC recorded under one sun
illumination, yielding a short circuit current density of 5.38 mA/cm2, an open circuit voltage
of 0.67 V and a fill factor of 35.6%. The inset shows Thiazovivin concentration the DSC. The NSs were produced by annealing LBZA NSs at 400°C. (b) The incident photon to charge carrier efficiency as a function of wavelength for the cell. We also fabricated resistive Adenosine triphosphate gas sensing devices using the same material with Figure 8 showing the effect of CO selleck screening library exposure on the resistance of a film of ZnO NSs obtained by annealing LBZA NSs at 400°C. The graph shows that the response, defined as R(air)/R(CO), was 1.65, 1.48, 1.32, 1.22 and 1.13 at 200, 100, 50, 25 and 12.5 ppm of CO, respectively. The response time was under 30 s for 100 ppm, whilst the recovery time was 40 s. Figure 8 demonstrates the stability of the sensing and highlights the potential of the material for this application. The sensitivity could be improved further by optimization of the thickness and cohesion of the films using organic binders. Figure 8 Resistance response to CO of a film of ZnO NSs at 350°C. The blue solid line shows the resistance versus time curve as various CO concentrations are mixed with the flowing dry air of the test chamber. The decreasing CO concentrations, from 200 to 12.5 ppm, are shown by the dashed red line. The inset shows the response of the sensing film as a function of CO concentration. Conclusion We report a novel technique for the production of ZnO nanocrystalline NSs through thermal decomposition of LBZA NSs.