Engineering electrode interfaces for telecom-band photodetection in MoS_(2)/Au heterostructures via sub-band light absorption

Transition metal dichalcogenide(TMD)layered semiconductors possess immense potential in the design of photonic,electronic,optoelectronic,and sensor devices.However,the sub-bandgap light absorption of TMD in the range from near-infrared(NIR)to short-wavelength infrared(SWIR)is insufficient for applications beyond the bandgap limit.Herein,we report that the sub-bandgap photoresponse of MoS_(2)/Au heterostructures can be robustly modulated by the electrode fabrication method employed.We observed up to 60%sub-bandgap absorption in the MoS_(2)/Au heterostructure,which includes the hybridized interface,where the Au layer was applied via sputter deposition.The greatly enhanced absorption of sub-bandgap light is due to the planar cavity formed by MoS_(2) and Au;as such,the absorption spectrum can be tuned by altering the thickness of the MoS_(2) layer.Photocurrent in the SWIR wavelength range increases due to increased absorption,which means that broad wavelength detection from visible toward SWIR is possible.We also achieved rapid photoresponse(~150μs)and high responsivity(17 mA W^(-1))at an excitation wavelength of 1550nm.Our findings demonstrate a facile method for optical property modulation using metal electrode engineering and for realizing SWIR photodetection in wide-bandgap 2D materials.

Hybridisation of perovskite nanocrystals with organic molecules for highly efficient liquid scintillators

Compared with solid scintillators,liquid scintillators have limited capability in dosimetry and radiography due to their relatively low light yields.Here,we report a new generation of highly efficient and low-cost liquid scintillators constructed by surface hybridisation of colloidal metal halide perovskite CsPbA_(3)(A:Cl,Br,I)nanocrystals(NCs)with organic molecules(2,5-diphenyloxazole).The hybrid liquid scintillators,compared to state-of-the-art CsI and Gd_(2)O_(2)S,demonstrate markedly highly competitive radioluminescence quantum yields under X-ray irradiation typically employed in diagnosis and treatment.Experimental and theoretical analyses suggest that the enhanced quantum yield is associated with X-ray photon-induced charge transfer from the organic molecules to the NCs.High-resolution X-ray imaging is demonstrated using a hybrid CsPbBr_(3) NC-based liquid scintillator.The novel X-ray scintillation mechanism in our hybrid scintillators could be extended to enhance the quantum yield of various types of scintillators,enabling low-dose radiation detection in various fields,including fundamental science and imaging.