Alpha Lead Oxide (α‐PbO): A New 2D Material with Visible Light Sensitivity

Abstract

Even though transition metal dichalcogenides (TMDCs) are deemed to be novel photonic and optoelectronic 2D materials, the visible band gap being often limited to monolayer, hampers their potential in niche applications due to fabrication challenges. Uncontrollable defects and degraded functionalities at elevated temperature and under extreme environments further restrict their prospects. To address such limitations, the discovery of a new 2D material, α-PbO is reported. Micromechanical as well as sonochemical exfoliation of 2D atomic sheets of α-PbO are demonstrated and its optical behavior is investigated. Spectroscopic investigations indicate layer dependent band gaps. In particular, even multilayered PbO sheets exhibit visible band gap > 2 eV (direct) which is rare among semiconducting 2D materials. The emission lifetime of multilayer PbO atomic sheets is 7 ns (dim light) as compared to the monolayer which gives 2.5 ns lifetime and an intense light. Density functional theory calculations of layer dependent band structure of α-PbO matches well with experimental results. Experimental findings suggest that PbO atomic sheets exhibit hydrophobic nature, thermal robustness, microwave stability, anti-corrosive behaviour and acid resistance. This new low-cost, abundant and robust 2D material is expected to find many applications in the fields of electronics, optoelectronics, sensors, photocatalysis and energy storage.

Porous Pb-Doped ZnO Nanobelts with Enriched Oxygen Vacancies: Preparation and Their Chemiresistive Sensing Performance

“…The two peaks at about 138.71 eV and 143.45 eV, of which the peak area ratio was approximately 4:3, were observed and assigned as Pb 4f 7/2 and Pb 4f 5/2 orbitals, respectively [23]. It exactly matches the previous report, concerning other possible valence states, such as PbO 2 and Pb 3 O 4 [24][25][26]. Meanwhile, the peak located here at about 139.56 eV is recognized as Zn 3s, presenting a high intensity because of the large atomic ratio between the Zn and Pb elements [27].…”

State of the Art in Alcohol Sensing with 2D Materials

“…As an example, ultrathin 2D nanomaterials, especially single-layer nanosheets, where interlayer interactions are absent or limited, prepare the media suitable for unique electrical properties compared to other nanomaterials [42]. They also possess exceptional properties, due to their finite bandgap, superior flexibility, absence of dangling bonds, and significant resistance to short channel effects, which all could suggest a new generation of smart electronic, optoelectronic, and energy devices [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59], where the first two promise the modern generation of sensors and biosensors and the last one offers developed, long lasting batteries, and energy devices. In addition, 2D layered nanomaterials are advantageous for gas sensing application specifically due to their large surface area, which facilitates surface reactions [60].…”

Vibrational spectra of MO (M = Sn/Pb) in their bulk and single-layer forms: role of avoided crossing in their thermodynamic properties

“…At present, atomic layers of MO (M=Sn/Pb) have been successfully fabricated using micromechanical and sonochemical exfoliation. 7,8 Because of the various band gaps, these materials have attracted attention for their electronic, optoelectronic and thermoelectric applications. 9 Tin monoxide (SnO) is an interesting semiconductor which possesses a relatively small indirect band gap of 0.7 eV and optical gap of 2.7 eV in bulk.…”