Black dye, coded N749, solutions with different concentration of deoxycholic acid (DCA) were prepared and effect of DCA concentration on photovoltaic property was investigated. Photocurrent density was improved by addition of DCA ranging between 2 mM and 20 mM, while little changes in voltage and fill factor were observed. High concentration of 100 mM DCA, however, deteriorated photovoltaic performance due to the significant decrease in photocurrent density. Photocurrent density of 15.6 mA/cm 2 observed without DCA was improved to 16.5 mA/cm 2 after addition of 10 mM DCA in N749 solution, while the amount of the adsorbed dye was decreased from 60.9 mmol to 51.3 mmol per cubic centimeter of TiO 2. Based on changes in photocurrent density and amount of the adsorbed dye, the faction of dye aggregation, which could not contribute to photocurrent generation, was estimated to be about 40%. The large fraction of dye aggregation was thus responsible for low photocurrent density, which could be resolved by addition of DCA. Based on an optimal condition of 10 mM DCA and 30-μm-thick TiO 2 film with light scattering layer, conversion efficiency of 9.1% was demonstrated at full sun illumination.
Bibliographical noteFunding Information:
This work was supported by the National Agenda Project (NAP) funded by the Korea Institute of Science and technology , the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education, Science and Technology (MEST) of Korea under contracts No. 2011-0016441 (2011) and the Korea Institute of Energy Technology Evaluation and planning (KETEP) grant funded by the Ministry of Knowledge Economy under contract No. 20103020010010.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry