PbS/CdS-sensitized mesoscopic SnO2 solar cells for enhanced infrared light harnessing

Abstract

Metal oxide semiconductors with lower lying conduction band minimum and superior electron mobility are essential for efficient charge separation and collection in PbS-sensitized solar cells. In the present study, mesoscopic SnO(2) was investigated as an alternative photoanode to the commonly used TiO(2) and examined comprehensively in PbS-sensitized liquid junction solar cells. To exploit the capability of PbS in an optimized structure, cascaded nPbS/nCdS and alternate n(PbS/CdS) layers deposited by a successive ionic layer adsorption and reaction method were systematically scrutinized. It was observed that the surface of SnO(2) has greater affinity to the growth of PbS compared with TiO(2), giving rise to much enhanced light absorption. In addition, the deposition of a CdS buffer layer and a ZnS passivation layer before and after a PbS layer was found to be beneficial for efficient charge separation. Under optimized conditions, cascaded PbS/CdS-sensitized SnO(2) exhibited an unprecedented photocurrent density of 17.38 mA cm(-2) with pronounced infrared light harvesting extending beyond 1100 nm, and a power conversion efficiency of 2.23% under AM 1.5, 1 sun illumination. In comparison, TiO(2) cells fabricated under similar conditions showed much inferior performance owing to the less efficient light harnessing of long wavelength photons. We anticipate that the systematic study of PbS-sensitized solar cells utilizing different metal oxide semiconductors as electron transporters would provide useful insights and promote the development of semiconductor-sensitized mesoscopic solar cells employing panchromatic sensitizers.

Quantum dot sensitized solar cell: Recent advances and future perspectives in photoanode

“…In another study of SnO 2 based solar cell, Hossain et al used PbS QDs along with CdS buffer layer and ZnS passivation layer to prepare FTO/SnO 2 /CdS/PbS/CdS/ZnS photoanode architecture [126]. The device shows PCE of 2.2% which is superior to bare TiO 2 based solar cell while short circuit current is enhanced up to 17.38 mA cm À 2 from 7.08 mA cm À 2 .…”

“…Materials for active layer of WBG SC in QDSSC can be selected among well known metal oxides that are frequently used in solar cells such as TiO 2 , ZnO and SnO 2 [14,15,50,73,[113][114][115][116][117][118][119][120][121][122][123][124][125][126]. Recently, some other types of WBG SC have been used by different research groups e.g.…”

Energetic alignment in nontoxic SnS quantum dot-sensitized solar cell employing spiro-OMeTAD as the solid-state electrolyte

“…Both devices usually employ a mesoporous layer of titanium dioxide nanoparticles as the backbone, which can then be made photoactive by sensitizing with semiconductor quantum dots using various kinds of methods including chemical bath deposition (CBD), successive ionic layer adsorption and reaction (SILAR), electrophoretic deposition and so on. For QD candidates, II-VI series semiconductors (such as CdS [7, 8], CdSe [2], CdS/CdSe [3, 4], CdTe/CdSe [6]) based solar cells have been a research hotspot, achieving an efficiency of nearly 5%–6%. Recently, IV-VI series ones with narrower band gap, such as PbS and PbSe, are also surging very quickly, catching up to the efficiency of Cd-based solar cells thanks to their wider sunlight absorption range extended to the near-infrared region [7–10].…”

“…For QD candidates, II-VI series semiconductors (such as CdS [7, 8], CdSe [2], CdS/CdSe [3, 4], CdTe/CdSe [6]) based solar cells have been a research hotspot, achieving an efficiency of nearly 5%–6%. Recently, IV-VI series ones with narrower band gap, such as PbS and PbSe, are also surging very quickly, catching up to the efficiency of Cd-based solar cells thanks to their wider sunlight absorption range extended to the near-infrared region [7–10]. However, the severe toxicity of Cd or Pb, which will cause hazardous damage to human bodies, definitely hampers their future application.…”

Preparation of nano-flower-like SnO2 particles and their applications in efficient CdS quantum dots sensitized solar cells

“…Subsequently, the mixture was transferred into a Teflon-lined stainless steel autoclave and kept at 160°C for 24 h. After hydrothermal procedure, the autoclave was cooled down to room temperature. The precipitates were collected by centrifugation, washed several times with deionized water and ethanol, respectively, and dried at 80°C for 12 h. Finally, the NF-SnO 2 particles were obtained by annealing the precipitates at 500°C for 2.5 h in air [18].…”