Highly efficient CdS/CdSe-sensitized solar cells controlled by the structural properties of compact porous TiO2 photoelectrodes

Abstract

At present, the photovoltaic performance of quantum dot-sensitized solar cells (QDSCs) is still much lower than conventional DSCs. Appropriate porous TiO(2) photoanodes for QDSCs need to be further investigated, and optimization of the nanoparticle-based photoanodes is highly desirable as well. In this article, the influence of the structural properties of various TiO(2) photoanodes on CdS/CdSe-sensitized solar cells have been systematically studied. Quantitative analyses of light-harvesting efficiency (LHE) and electron-transfer yield (Φ(ET)) for the QDSCs are investigated for the first time. It is revealed that the LHE increases in the long wavelength region with the addition of large size TiO(2) particles to the transparent film. In the meantime, the balance between the light scattering and surface area also needs to be controlled, which can significantly restrain the dark current of the device. A double-layer photoanodic structure can give 4.92% of light-to-electricity conversion efficiency with a photoactive area of 0.15 cm(2).

Effect of nanostructured electrode architecture and semiconductor deposition strategy on the photovoltaic performance of quantum dot sensitized solar cells

“…We have paid special attention to the effect of both issues on the device photovoltage, V oc , since this parameter conveys the main current limitation of QDSCs. Current V oc values for QDSCs lay significantly below those reported for DSCs [22], while photocurrents, J sc , as high as 18.4 mA/cm 2 [16], and fill factors, FF, higher than 0.62, reported for QDSCs [23], which are close to the values reported for high efficient DSCs.…”

“…The direct growth of semiconductor QDs on the surface of the nanostructured electrode does not allow a fine control of the QDs properties, but produces a significant higher QD loading, increasing the solar cell photocurrent. In fact the highest efficiencies reported for QDSCs have been reported using a direct growth method [1,5,23].…”

“…There are two main approaches for QD sensitization: i) to use previously synthesized colloidal QDs [13,29,30] and ii) to directly grow the QD on the surface of the wide bandgap semiconductor [12,19,20,23,33]. The direct growth of semiconductor QDs on the surface of the nanostructured electrode does not allow a fine control of the QDs properties, but produces a significant higher QD loading, increasing the solar cell photocurrent.…”

High performance PbS Quantum Dot Sensitized Solar Cells exceeding 4% efficiency: the role of metal precursors in the electron injection and charge separation

“…15 However, the photovoltaic efficiency of solar cells with colloidal QDs is significantly enhanced when inverted type-I CdS/CdSe core/shell QDs are employed. 22 In order to increase QD loading, in-situ growth of the inorganic semiconductor on nanostructured photoanode can be carried out by low cost solution techniques as Chemical Bath Deposition (CBD) 16,[23][24][25] or Successive Ionic Layer Absorption and Reaction (SILAR). [26][27][28] The advantage of higher QD loading is partially balanced by the lower control over the QD growth conditions.…”

Co-sensitized TiO2 Photoelectrodes by Multiple Semiconductors (Pbs/Pb0.05Cd0.95S/Cds)to Enhance the Performance of a Solar Cell

“…To improve the performance of QDSSCs, various nanostructures have been employed to fabricate the photoanodes, such as mesoporous lms [7][8][9] , hierarchical sphere 10 , nanowires (NWs), nanorods (NRs) and nanotubes (NTs) arrays. Recently, many new strategies, especially the surface and interface treatment, were also employed to modify the nanostructures of the photoanodes, aiming to reduce the recombination and improve the transport of the photo-excited carriers at the interface 10 .…”