Improving the performance of colloidal quantum-dot-sensitized solar cells

SIXTO GIMÉNEZ; IVÁN MORA-SERÓ; LORENA MACOR; NESTOR GUIJARRO; TERESA LANA-VILLARREAL; ROBERTO GÓMEZ; LINA J DIGUNA; QING SHEN; TARO TOYODA; JUAN BISQUERT

NANOTECHNOLOGY

IOP PUBLISHING LTD

Lugar: Bristol; Año: 2009 vol. 20 p. 295204 - 295210

0957-4484

Abstract: Solar cells based on a mesoporous structure of TiO2 and the polysulfide redox electrolyte  were prepared by direct adsorption of colloidal CdSe quantum dot light absorbers onto the oxide without any particular linker. Several factors cooperate to improve the performance of quantum-dot-sensitized solar cells: an open structure of the wide bandgap electron collector, which facilitates a higher covering of the internal surface with the sensitizer, a surface passivation of TiO2 to reduce recombination and improved counter electrode materials. As a result, solar cells of 1.83% efficiency under full 1 sun illumination intensity have been obtained. Despite a relatively large short circuit current (Jsc = 7.13 mA cm -2) and open circuit voltage (Voc = 0.53 V), the colloidal quantum dot solar cell performance is still limited by a low fill factor of 0.50, which is believed to arise from charge transfer of photogenerated electrons to the aqueous electrolyte.