I have used carbon quantum dots (CQD) as a co-sensitizing agent in the dye-sensitized solar cell. The photoanodes were made using TiO2 anatase paste by doctor blade technique. TiO2 anatase paste was prepared using 0.65 gram ethyl cellulose, 8 ml Terpineol, and 5 gram TiO2 anatase powder. Photoanodes were sintered at 450C for 1 hour. CQD absorption was done by soaking the photoanodes in the CQD solution for 6,12 and 24 hours and N719 (1mM, 0.5 mM) dye was used for sensitizer. When the CQD was doped, the photocurrent and the IPCE value were always lower than without CQD loaded photoanodes in my solar cell. Why does this happen? In most papers when the CQD/GQD is used, the photocurrent and IPCE values are increased, but not in my sample. How can I overcome this problem?
Could you explain the possible reasons? Your suggestions will be highly appreciated.
One possible reason for the lower performance of the CQD-loaded photoanodes could be incomplete coverage of the TiO2 surface by the CQDs. If the CQDs do not fully cover the TiO2 surface, they may not be able to efficiently inject electrons into the TiO2 conduction band, leading to lower photocurrent and IPCE values. Another possible reason could be lower dye loading on the CQD-loaded photoanodes. If the CQDs occupy some of the surface area that would otherwise be available for dye adsorption, the dye loading may be reduced, leading to lower photocurrent and IPCE values. Also, If the CQDs are not dispersed uniformly in the solution or on the TiO2 surface, they may form aggregates that can block the TiO2 surface and prevent efficient electron injection, leading to lower photocurrent and IPCE values. The presence of CQDs may increase the rate of charge recombination in the DSSC, leading to lower photocurrent and IPCE values. This could occur if the CQDs act as electron traps, or if they interfere with the electron transport from the TiO2 conduction band to the counter electrode.
Zaiba Zafar Thank you for your valuable comments. How can we doped CQD on TiO2 surface so that it can cover the whole TiO2 surface?
You should first prepare the TiO2 surface i.e. it should be cleaned and activated before doping the CQDs onto it. This can be done by rinsing the surface with a solvent such as ethanol or isopropyl alcohol and then annealing it at a high temperature to remove any residual impurities.The CQDs can be deposited onto the TiO2 surface using the specific method. The size and surface chemistry of the CQDs can be tailored to achieve optimal coverage and adhesion to the TiO2 surface. The key is to optimize the parameters such as solution concentration, deposition time, and annealing temperature to achieve uniform coverage and adhesion.
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Biochemical Techniques
- Analytical Chemistry
- pH