## 3 Results and Discussions
### Photovoltaic Properties
#### 3.3.1 Lhe  
LHE in a DSSC represents the proportion of photons in the incident light that is absorbed by the dye, contributing to the formation of electron-hole pairs. The calculation of LHE involves the total of the dye's optical density, light absorption coefficient, and quantum yield from electron injection into the semiconductor [32]. LHE is a crucial metric, reflecting the dye's ability to capture incoming light and transform it into an excited state. In DSSCs, effective energy conversion relies on the dye's capacity to absorb light and generate excited states, with a higher LHE indicating improved power conversion efficiency. LHE in a DSSC can be influenced by various factors, including the choice of the dye and electrolyte, the thickness of the dye layer, and the shape and quality of the semiconductor layer. To enhance the photocurrent response, a high LHE is essential. The LHE values are calculated by using the below Equation (1) [33]. \[\text{LHE}=1-10^{-f} \tag{1}\]  
where:  
LHE = Light harvesting efficiency  
\(f\) = Oscillator strength. Table 3 displays the values of LHE for the natural dyes in both the gas and solvent phases based on the information given. In the gas phase, the increasing order of LHE values is petunidin = delphinidin > pelargonidin > cyanidin = peonidin, and this order is maintained in the solvent phase. Among the dyes examined, petunidin and delphinidin exhibit the highest LHE values in both the gas and solvent phases. This suggests that petunidin and delphinidin have substantial electron-donating capabilities, allowing them to effectively absorb and change incoming light into excited states. Petunidin and delphinidin have powerful electron-donating characteristics, which contribute to their higher LHE values and suggest their potential as good candidates for DSSC applications. Petunidin and delphinidin are advantageous sensitizers for improving the overall performance of DSSCs due to their capacity to efficiently capture light energy \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & \multicolumn{6}{c}{**Vacuum (Gas) Phase**} \\ \hline
**Dye Molecule** & **LHE** & \(E^{type}\) **(eV)** & \(\Delta G^{injct}\) **(eV)** & \(\Delta G^{region}\) **(eV)** & \(V_{OC}\) **(eV)** & \(1\,V_{RP}\) **(eV)** & \(\tau\) **(ns)** & \(\eta\) * **(\%)** \\ \hline Cyanidin & 0.001 & \(-6.572\) & \(-10.572\) & \(1.1738\) & 0.2726 & \(-4.0238\) & 70.400 & - \\ Delphinidin & 0.006 & \(-7.820\) & \(-11.820\) & \(1.1860\) & 0.7910 & \(-4.0360\) & 43.860 & - \\ Pelargonidin & 0.003 & \(-7.132\) & \(-11.132\) & \(1.2568\) & \(-0.3125\) & \(-4.1068\) & 39.040 & - \\ Peonidin & 0.001 & \(-6.496\) & \(-10.496\) & \(1.1036\) & \(0.3950\) & \(-3.9536\) & 7.078 & - \\ Petunidin & 0.006 & \(-7.806\) & \(-11.806\) & \(1.1716\) & \(0.8032\) & \(-4.0216\) & 17.170 & - \\ \hline \hline \multicolumn{8}{c}{Ethanol Solvent Phase} \\ \hline Cyanidin & 0.001 & \(-6.609\) & \(-10.609\) & \(1.2051\) & 0.3071 & \(-4.0551\) & 86.720 & 0.56 [34] \\ Delphinidin & 0.006 & \(-7.891\) & \(-11.891\) & \(1.2562\) & 0.6775 & \(-4.1062\) & 19.140 & 0.61 [35] \\ Pelargonidin & 0.005 & \(-7.174\) & \(-11.174\) & \(1.2761\) & \(-0.2801\) & \(-4.1261\) & 29.820 & 0.60–0.68 \\ Peonidin & 0.001 & \(-6.538\) & \(-10.538\) & \(1.1390\) & \(-0.1489\) & \(-3.9890\) & 17.590 & 0.87 [37] \\ Petunidin & 0.006 & \(-7.910\) & \(-11.910\) & \(1.2728\) & 0.6748 & \(-4.1228\) & 17.190 & 0.69 [38] \\ \hline \hline \end{tabular}  
* The symbol \(\eta\) represents the experimental efficiency of DSSCs sensitized with these dyes in ethanol for comparison.  
\end{table} 
Table 3: Photovoltaic properties of studied molecules in the gas and ethanol solvent phases. and produce excited states. Regarding the abnormality observed in the sign change of \(\mathrm{peonidin}\) V\({}_{\mathrm{OC}}\) from the gas phase to the solvent phase, it may be attributed to interactions between \(\mathrm{peonidin}\) and ethanol molecules when applying the solvent model.