Engineering Geometric Electrodes for Electric Field-Enhanced High-Performance Flexible In-Plane Micro-Supercapacitors

In plane micro-supercapacitors that are miniaturized energy storage components have attracted significant attention due to their high power densities for various ubiquitous and sustainable device systems as well as their facile integration on various flexible/wearable platform.To implement the micro-supercapacitors in various practical applications that can accompany solid state or gel electrolyte and flexible substrates,ions must be readily transported to electrodes for achieving high power densities.Herein,we show large enhancement in electrochemical properties of flexible,inplane micro-supercapacitor using sharp-edged interdigitated electrode design,which was simply fabricated through direct laser scribing method.The sharp-edged electrodes allowed strong electric field to be induced at the corners of the electrode fingers which led to the greater accumulation of ions near the surface of electrode,significantly enhancing the energy storage performance of micro-supercapacitors.The electric field-enhanced in-plane micro-supercapacitor showed the volumetric energy density of 1.52 Wh L^(−1)and the excellent cyclability with capacitive retention of 95.4%after 20000 cycles.We further showed various practicability of our sharp-edged design in micro-supercapacitors by showing circuit applicability,mechanical stability,and air stability.These results present an important pathway for designing electrodes in various energy storage devices.

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.