Dear Habtamu Fekadu,

The +ve charges/holes are responsible for conductivity in p-type semiconductors, therefore you have to calculate the HOMO/VB on energy scale wrt to dye and CDs to understand more about the charge separation/ transportation inside of photoanode upon illumination.

Here I copy the link through which the role of CDs can be understood (CDs are in QDSCs). Article Lead Selenide Quantum Dots and Carbon Dots Amplify Solar Con...

ATB

Dr Naresh

Dear Habtamu,

The carbon dots or called carbon quantum dots possess the attractive properties of high stability, good conductivity and low toxicity as well as comparable optical properties to the spectrum of a DSSC or solar cell. Recent research outcomes on carbon dots combining metal oxides i.e. TIOx as p-type layer of DSSC are strongly suggested that carbon dots can be used as photosensitizer in dye sensitized solar cells, thereby enhancing the photoelectric conversion efficiency significantly. It shows a great promise for low cost photosensitizer. There is one article from researchgate forum that can explain further. Please see the attached. Hope it helps.

Xuhua

Dear Naresh

I thank you for your response.after i decide HUMO/CB of them what is the expectation? please explain for me .because p-type system is a little bit difference from n-type semiconductor in DSSC.

Dear Xuhua Wang i like your explanation thanks very much i hope you have more experience on this area