Preparation And Photovoltaic Performance Of Hybrid SnS₂-PbS Quantum Dots

Recently, photodetectors based on 2D layered materials have attracted much attention due to its high mobility. And the common roadblock is the limited spectral selectivity which is determined by the bandgap of the material. Althought the 0D quantum dots?QDs? exhibit low mobility, QDs also have the advantages of high sensitivity and bandgap tunability. The hybrid 2D-0D material offers the potential to prepare a high-performance near-infrared photodetectors. In this dissertation, two materials SnS₂ and PbS QDs were prepared, and performance of the photodetector was studied, repectively. Then the hybird SnS₂-PbS QDs photodetector was tested. Details are as followed:?1? SnS₂ thin film was obtained by thermal evaporation, and its annealing process was optimized. The quality of SnS₂ thin film can be effectively improved, after annealed at 300? for 3 hours in sulphur vapour.The responsivity R and detectivity D* of the photodector was 47uA/W and 4.6×10⁶Jones;?2? Large quantities of uniform size SnS₂ flake can be prepared in a new method that was vulcanizing the Sn film in a sealed tube. The rise and decay time of the photodetector all are less than 1 ms. The responsivity R and detectivity D* is 0.33A/W and 5.8×109Jones. Ultra-low noise is about 6×10-16A/Hz which is the lowest value in the reported literature.?3? Different sizes of PbS QDs were synthesized by hot injection method. Then the effects of passivating PbS QDs by different concentrations of TBAI was studied. The responsivity R and detectivity D* is 121.6uA/W and 6.0×10⁷Jones when the PbS QDs was passivated by 10mg/m L TBAI;?4? Hybird SnS₂-PbS QDs photodetector broadened the absorption spectrum of SnS₂, and showed photoresponse to near-infrared light of 930 nm. The responsivity R and detectivity D* is 64.7mA/W and 2.6×10⁸Jones.