*Solar Cells - Theory, Materials and Recent Advances*


#### **Table 7.**

*Photocurrent-voltage characteristics of DSSC comprising only blocking layers for N719 dye [58].*

layers. However, TiCl4 treated ZnO anode has a larger flake, which can offer a large surface area to absorb much more dyes. **Table 8** lists the photovoltaic property of

*Effect of post TiCl4 treatment in the cell performance of TiO2 based DSSC [69].*

**Short-circuit current, Jsc (mA/cm<sup>2</sup>**

Without TiCl4 0.3977 1.07 0.2829 0.12 TiCl4 0.4759 2.86 0.3967 0.54

*Effect of Combination of Natural Dyes and the Blocking Layer on the Performance of DSSC*

*Photovoltaic performance of ZnO based DSSCs with TiCl4 pretreatment and without TiCl4 pretreatment [68].*

**)**

**Fill factor, FF Efficiency,**

**ɳ (%)**

Kabir et al. studied the effect of post-treatment of TiCl4 in TiO2 based DSSC. Post TiCl4 treatment not only increases the overall cell conversion efficiency of DSSC but also enhances cell stability. TiCl4 treated TiO2 anode based DSSC's degradation rate is much lower than the TiCl4 untreated TiO2 anode based DSSC. Studies showed that TiCl4 treated TiO2 anode based DSSC's cell stability of the increase around 38–44.5%. **Figure 20** shows the effect of post TiCl4 treatment in the cell

Cameron et al. [57], Heo et al. [70], Yu et al. [71] used spray coating method to

In conclusion, natural dye is a promising alternative to replace the metal complexes or organic dyes in the DSSC application. They are low-cost, abundant, ecofriendly, simple extraction procedures, and non-toxic. The combination of natural dyes with an optimized choice of the mixture of the volume ratio of the extracting dye extracting solvent accounts for many possible interactions that promise to provide more charge injection upon sensitization and allowed utilization of the photon energy more efficiently. DSSC co-sensitized with the dye mixture shows higher absorbance, and cumulative absorption properties over the entire visible

prepare TiO2 blocking layer. Introducing the blocking layer into the device decreases charge carrier trapping and recombination. Subsequently, short-circuit current increases significantly. Additionally, a slight improvement in the opencircuit voltage and fill factor is observed, thus cell efficiency enhances significantly.

DSSC with TiCl4 blocking layer [68].

**Samples Open-circuit voltage,**

*DOI: http://dx.doi.org/10.5772/intechopen.94760*

**Table 8.**

**Figure 20.**

**Voc (V)**

**5. Summary**

**331**

conversion efficiency of TiO2 based DSSC [69].

region than the DSSC fabricated with individual dyes.

#### **Figure 19.**

*SEM images of (a) FTO/ZnO with TiCl4 pretreatment. (b) FTO/ZnO without TiCl4 pretreatment. (c) and (d) the amplification figure of (a) and (b), respectively [68].*

*Effect of Combination of Natural Dyes and the Blocking Layer on the Performance of DSSC DOI: http://dx.doi.org/10.5772/intechopen.94760*


#### **Table 8.**

**Ti precursor concentration (M)**

**Table 7.**

**Figure 19.**

**330**

**Short-circuit current, Jsc (mA/cm<sup>2</sup>**

*Solar Cells - Theory, Materials and Recent Advances*

**)**

*Photocurrent-voltage characteristics of DSSC comprising only blocking layers for N719 dye [58].*

*SEM images of (a) FTO/ZnO with TiCl4 pretreatment. (b) FTO/ZnO without TiCl4 pretreatment. (c) and*

*(d) the amplification figure of (a) and (b), respectively [68].*

Without blocking layer 0.01 0.588 0.356 0.002 0.99 0.05 0.05 0.861 0.475 0.020 0.99 0.10 0.08 0.865 0.482 0.033 1.02 0.15 0.10 0.869 0.530 0.046 1.02 0.20 0.14 0.871 0.564 0.069 1.02 0.40 0.21 0.881 0.618 0.114 1.02 0.80 0.38 0.884 0.648 0.218 1.02 1.20 0.56 0.883 0.615 0.304 1.02

**Open-circuit voltage, Voc (V)**

**Fill factor, FF**

**Efficiency, ɳ (%)**

**Area (cm2 )**

*Photovoltaic performance of ZnO based DSSCs with TiCl4 pretreatment and without TiCl4 pretreatment [68].*

**Figure 20.** *Effect of post TiCl4 treatment in the cell performance of TiO2 based DSSC [69].*

layers. However, TiCl4 treated ZnO anode has a larger flake, which can offer a large surface area to absorb much more dyes. **Table 8** lists the photovoltaic property of DSSC with TiCl4 blocking layer [68].

Kabir et al. studied the effect of post-treatment of TiCl4 in TiO2 based DSSC. Post TiCl4 treatment not only increases the overall cell conversion efficiency of DSSC but also enhances cell stability. TiCl4 treated TiO2 anode based DSSC's degradation rate is much lower than the TiCl4 untreated TiO2 anode based DSSC. Studies showed that TiCl4 treated TiO2 anode based DSSC's cell stability of the increase around 38–44.5%. **Figure 20** shows the effect of post TiCl4 treatment in the cell conversion efficiency of TiO2 based DSSC [69].

Cameron et al. [57], Heo et al. [70], Yu et al. [71] used spray coating method to prepare TiO2 blocking layer. Introducing the blocking layer into the device decreases charge carrier trapping and recombination. Subsequently, short-circuit current increases significantly. Additionally, a slight improvement in the opencircuit voltage and fill factor is observed, thus cell efficiency enhances significantly.
