Synthesis of PbS/TiO₂ Colloidal Heterostructures for Photovoltaic Applications

Abstract

We report on heteroepitaxial growth of nearly monodisperse PbS nanocrystals onto the surface of TiO 2 nanoparticles via colloidal hot-injection routes. Fabricated PbS/TiO 2 nanocomposites can be dispersed in nonpolar solvents, which enables an easy solution processing of these materials into mesoporous films for use as light-absorbing layers in nanocrystal-sensitized solar cells. High-temperature deposition of the sensitizer material allows controlling both the size and the number of PbS domains grown onto TiO 2 nanoparticles, whereby providing synthetic means for tuning the absorbance spectrum of PbS/TiO 2 nanocomposites and simultaneously enhancing their photocatalytic response in the visible and near-infrared. Compared with conventional ionic bath deposition of PbS semiconductors onto TiO 2 , the reported method results in an improved nanocrystal quality and narrower distribution of PbS sizes; meanwhile, the use of hot-temperature deposition of PbS (T ) 180 °C) promotes the formation of near-epitaxial relationships between PbS and TiO 2 domains, leading to fewer interfacial defects. The photovoltaic response of pyridine-treated PbS/TiO 2 nanocomposites was investigated using a two-electrode cell filled with polysulfide electrolyte. The measured photocurrent compared favorably to that of PbS/TiO 2 electrodes fabricated via chemical bath deposition.

Effects of incorporating PbS quantum dots in perovskite solar cells based on CH3NH3PbI3

“…2c and d that the PbS QD size increases from~5 nm to~10 nm as the SILAR cycles are increased from 3 to 5. Due to the relationship between particle size and quantized energy levels in QDs, increasing PbS particle size leads to decreased PbS band gap and downshift of the PbS conduction band level [41]. For example, the PbS QD with a particle size of 5 nm has a CB level of À4.0 eV, while the one with a particle size of 10 nm has a CB level of À4.4 eV that is lower than that of TiO 2 (À4.2 eV) [42,43].…”

Synthesis, characterization and photoelectrochemical properties of PbS sensitized vertically aligned ZnO nanorods: modified aqueous route

“…It means that nanocrystalline PbS was properly coated on ZnO nanorods. Further with an increase in the number of SILAR cycles(15,25, 35 and 45) faint-dark brown to blackish brown colour was observed (as shown in…”

“…Also, different semiconductor nanomaterials have been used as a promising photosensitizer for ZnO and TiO 2 as quantum dots sensitized solar cell [10,11]. Inspired through the importance of oxide thin films photosensitization of ZnO/TiO 2 by various binary nanostructures such as, CdS [12], CdSe [13], CdTe [14], PbS [15] and PbSe [16] have been successfully studied as a light harvesting nanomaterials rather than costly and conventional organic dyes. However, lead chalcogenide (i.e.…”

Growth of axial nested P–N heterojunction nanowires for high performance diodes

“…Low dimensional inorganic-organic hybrids such as P-N junctions of nanostructures combine the functional organic and inorganic moieties to produce a new class of inorganic-organic solid materials with a distinct structure. r B = 18 nm) [25][26][27] that has applications in electronic devices, [28][29][30] photovoltaics, 31 optoelectronic devices, 32 mid-infrared lasers, 33,34 and thermoelectrics. 24) and a strong quantum confinement effect owing to its large Bohr radius (ca.…”