In this study, the effects of particle size, crystal phase and morphology on the overall solar cell performance were examined. It was found that the TiO₂ nanoparticle film with smaller particles ~10 nm in diameter resulted in a lower light-to-electricity conversion efficiency than larger particles with diameter of ~25 nm. Photoanode coated with larger particles had higher light harvesting efficiency due to better light scattering ability. Rutile and anatase are the most common forms of TiO₂ but anatase based DSSCs showed better photovoltaic performance. Electrochemical impedance spectroscopy (EIS) studies also revealed that the electron lifetime was longer and the charge transport was faster in anatase films. Meanwhile, a new photoanode material rutile nanobundle had been synthe...[ Read more ]

In this study, the effects of particle size, crystal phase and morphology on the overall solar cell performance were examined. It was found that the TiO₂ nanoparticle film with smaller particles ~10 nm in diameter resulted in a lower light-to-electricity conversion efficiency than larger particles with diameter of ~25 nm. Photoanode coated with larger particles had higher light harvesting efficiency due to better light scattering ability. Rutile and anatase are the most common forms of TiO₂ but anatase based DSSCs showed better photovoltaic performance. Electrochemical impedance spectroscopy (EIS) studies also revealed that the electron lifetime was longer and the charge transport was faster in anatase films. Meanwhile, a new photoanode material rutile nanobundle had been synthesized for the first time using conventional oven-drying method. The potential of rutile nanobundle for efficient DSSC had been demonstrated. It was shown to have higher electron mobility than the typical TiO₂ nanoparticle layer. The overall sunlight conversion efficiency for the nanobundle DSSC reached 7.9% with the incorporation of anatase nanoparticles. EIS measurement indicated that nanobundles photoanode possessed long electron lifetime and high electron mobility facilitating charge transport. The stability test showed that this 1D hierarchical DSSC had durable performance at room conditions for more than a week making it suitable future applications with further improvement.