(Figure Presented) The energy levels of CdS quantum dots (QDs) can be shifted in a systematic fashion with respect to the TiO2 bands using molecular dipoles. Dipole moments pointing toward the QD surface shift the energy levels toward the vacuum level (a), thus enabling electron injection from excited QD states into the TiO2 conduction band at lower photon energies compared to QDs with adsorbed molecular dipoles which are pointing away from the QD surface (b). In CdS QD sensitized solar cells this leads to a dipole dependent shift of the photovoltage onset and the photocurrent.
ASJC Scopus subject areas
- Chemistry (all)
- Colloid and Surface Chemistry