Effect of the interface on UV–vis–IR photodetection performance of PbS/ZnO nanocomposite photocatalysts

Sun, Jie; Li, Yuanzhi; Yang, Yi; Bai, Jilin; Zhao, Xiujian

doi:10.1016/j.apsusc.2015.05.112

Cited by 11 publications

(5 citation statements)

References 52 publications

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“…(a) Band diagram at PbS/ZnO interface (after Sun et al and Ehrler et al). (b) Normalized change in microwave conductivity for PbS-on-quartz (red symbols) and PbS-on-ZnO (blue symbols) samples for 0.5 ms following a ∼10 ns illumination pulse at 905 nm.…”

Section: Resultsmentioning

confidence: 99%

“…ZnO has been suggested as an electron collector in ZnO/PbS quantum dot heterojunction solar cells, as quantum confinement increases the PbS band gap and results in band alignment favoring injection of electrons from PbS quantum dots into ZnO. 7,9,11,16,50 As discussed earlier, studies using transient optical absorption, time-resolved photoluminescence, and time-resolved surface photovoltage spectroscopy have demonstrated rapid decay of photoexctited carrier density over sub-picosecond timescales in PbS nanocrystals in the presence of ZnO. 7,8,16 In the case of bulk-like, small band gap PbS, Fermi level equilibration may either in injecting result in a noninjecting (1) or an injecting (2) junction, as illustrated schematically in Figure 4a.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…Narrow band gap in the bulk makes lead sulfide (PbS) an attractive choice for infrared optoelectronic devices including photodetectors and solar cells that can efficiently utilize the infrared range of the solar spectrum. − The possibility of generating multiple carriers for one absorbed photon has been demonstrated in both bulk PbS and PbS quantum dots, bringing forth the possibility of PbS photovoltaics with efficiencies that exceed the Shockley–Queisser limit . Efficient carrier extraction in PbS optoelectronic devices can be achieved by forming p–n heterojunctions between a p-type PbS absorber and n-type wide band gap transparent metal oxide semiconductors such as ZnO or TiO 2 , where the band alignment favors rapid injection of electrons from PbS into the oxide. − …”

Section: Introductionmentioning

confidence: 99%

“…Heterojunction interfaces play a crucial role in device performance, as they often harbor a variety of trap states and recombination centers. Surface states at PbS grain boundaries serve as efficient electron traps, and trap-mediated carrier recombination at PbS/ZnO interfaces limits the performance of PbS/ZnO heterojunction photovoltaics and other optoelectronic devices. ,,,− Recent studies using transient optical absorption and time-resolved photoluminescence have demonstrated that lifetimes of photoexcited carriers in PbS quantum dots are reduced in the vicinity of PbS/ZnO interfaces, suggesting carrier injection from PbS quantum dots into ZnO. , However, the ultrafast dynamics of photoexcited carriers in bulk-like, small band gap polycrystalline PbS and at the interfaces of polycrystalline PbS with metal oxide electron collectors have not yet been elucidated. Revealing such photoexcited carrier dynamics motivates the present investigation.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Photoexcited Carriers in Polycrystalline PbS and at PbS/ZnO Heterojunctions: Influence of Grain Boundaries and Interfaces

et al. 2018

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We investigate the impact of grain boundaries and interfaces on dynamics of photoexcited charge carriers in polycrystalline lead sulfide (PbS) films and at interfaces between polycrystalline PbS and ZnO by studying transient photoconductivity over sub-picoseconds to microseconds timescales using timeresolved terahertz spectroscopy and time-resolved microwave conductivity measurements. Narrow band gap bulk-like polycrystalline PbS with high absorption in the infrared paired with wide band gap metal oxide current collectors holds promise for infrared photodetectors and photovoltaics for converting infrared radiation to electricity. We find that grain boundaries in polycrystalline PbS suppress long-range conductivity and confine photoexcited carriers within individual crystallites. The mobility of photoexcited holes inside the ∼150 nm crystallites reaches 750 cm 2 /V s, and their lifetime exceeds hundreds of microseconds, while electrons get rapidly trapped at grain boundary states. The presence of PbS/ZnO interfaces dramatically reduces the lifetime of the photoexcited free holes in the PbS crystallites. Moreover, we detect no injection of free electrons from PbS to ZnO. Optimal transfer of photoexcited electrons, as is needed for optoelectronic devices with PbS/ZnO heterojunctions, may require engineering PbS/ZnO heterojunctions with buffer layers or organic ligands to passivate deleterious interface states.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamics of Photoexcited Carriers in Polycrystalline PbS and at PbS/ZnO Heterojunctions: Influence of Grain Boundaries and Interfaces

et al. 2018

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“…0.5 eV or less, as shown in [109]). Still, it has been considered for photocatalysis in combination with other phases [110,111]. This work will concentrate in the experience of our lab with three simple sulfides including octahedral coordination: In 2 S 3 , SnS 2, and ZnIn 2 S 4 .…”

Section: Sulfides Including 6-fold Coordinated Cationsmentioning

confidence: 99%

Sulfide-Based Photocatalysts Using Visible Light, with Special Focus on In2S3, SnS2 and ZnIn2S4

Conesa

2021

Catalysts

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Sulfides are frequently used as photocatalysts, since they absorb visible light better than many oxides. They have the disadvantage of being more easily photocorroded. This occurs mostly in oxidizing conditions; therefore, they are commonly used instead in reduction processes, such as CO2 reduction to fuels or H2 production. Here a summary will be presented of a number of sulfides used in several photocatalytic processes; where appropriate, some recent reviews will be presented of their behaviour. Results obtained in recent years by our group using some octahedral sulfides will be shown, showing how to determine their wavelength-dependent photocatalytic activities, checking their mechanisms in some cases, and verifying how they can be modified to extend their wavelength range of activity. It will be shown here as well how using photocatalytic or photoelectrochemical setups, by combining some enzymes with these sulfides, allows achieving the photo-splitting of water into H2 and O2, thus constituting a scheme of artificial photosynthesis.

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An Enhanced UV–Vis–NIR an d Flexible Photodetector Based on Electrospun ZnO Nanowire Array/PbS Quantum Dots Film Heterostructure

et al. 2016

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ZnO nanostructure‐based photodetectors have a wide applications in many aspects, however, the response range of which are mainly restricted in the UV region dictated by its bandgap. Herein, UV–vis–NIR sensitive ZnO photodetectors consisting of ZnO nanowires (NW) array/PbS quantum dots (QDs) heterostructures are fabricated through modified electrospining method and an exchanging process. Besides wider response region compared to pure ZnO NWs based photodetectors, the heterostructures based photodetectors have faster response and recovery speed in UV range. Moreover, such photodetectors demonstrate good flexibility as well, which maintain almost constant performances under extreme (up to 180°) and repeat (up to 200 cycles) bending conditions in UV–vis–NIR range. Finally, this strategy is further verified on other kinds of 1D nanowires and 0D QDs, and similar enhancement on the performance of corresponding photodetecetors can be acquired, evidencing the universality of this strategy.

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Effect of the interface on UV–vis–IR photodetection performance of PbS/ZnO nanocomposite photocatalysts

Cited by 11 publications

References 52 publications

Dynamics of Photoexcited Carriers in Polycrystalline PbS and at PbS/ZnO Heterojunctions: Influence of Grain Boundaries and Interfaces

Dynamics of Photoexcited Carriers in Polycrystalline PbS and at PbS/ZnO Heterojunctions: Influence of Grain Boundaries and Interfaces

Sulfide-Based Photocatalysts Using Visible Light, with Special Focus on In2S3, SnS2 and ZnIn2S4

An Enhanced UV–Vis–NIR an d Flexible Photodetector Based on Electrospun ZnO Nanowire Array/PbS Quantum Dots Film Heterostructure

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