Lily (Iris Persica) pigments as new sensitizer and TiO2 nanofibers as photoanode electrode in dye sensitized solar cells

Abstract

In this study, lily (Iris Persica) dyes as sensitizer were examined by UV–vis and FTIR analyses. Corresponding results showed that lily pigments effectively absorb incident light. This was mainly due to the presence of functional groups such as CO and OH in the pigment structure appeared on the FTIR analysis. This shows the appropriateness of lily pigment as sensitizer. On the other hand, anatase TiO2 nanofibers with different diameters were synthesized by Electrospinning method, using Titanium isopropoxide (TIPP) and polyvinylpyrrolidone (PVP) solution. The Electrospinning feed rate was altered from 0.1 to 0.5 mL/h to control the diameter of the TiO2 nanofibers. Other effective parameters including voltage, needle tip distance to collector and speed of collector were 25 kV, 15 cm and 500 rpm, respectively and were kept constant during synthesizing of nanofibers. The Synthesized nanofibers were analyzed and characterized by means of SEM, FESEM, XRD and TEM techniques. The FESEM and XRD analyses indicated that the nanofiber's diameter and crystallinity increase with increase in feed rate. The fabricated DSSC with 430 nm TiO2 nanofibers (obtained from flow rate of 0.3 mL/h) provided 1.72 % energy conversion efficiency (ղ), 50.78 % conversion efficiency of photon to electron (IPCE), short-circuit current density (JSC) of 2.716 mA/cm2 and open circuit voltage (VOC) of 0.738 V. The efficiency of the developed DSSCs, in comparison with the previously fabricated similar cells, were found higher, due to more effective absorption of light by the dyes and adsorption of pigment by nanofibers.