Revisiting Metal Sulfide Semiconductors: A Solution‐Based General Protocol for Thin Film Formation, Hall Effect Measurement, and Application Prospects

Abstract

5739wileyonlinelibrary.com deposition method, which is facile, benign, and which can deposit a uniform MS thin fi lms is highly desirable. Although various available techniques such as chemical vapor deposition, [ 9,10 ] atomic layer deposition, [ 11,12 ] molecular beam epitaxy, [ 13,14 ] electrodeposition, [ 7,15 ] successive ionic layer adsorption and reaction, [ 16,17 ] vapor sublimation, [ 18 ] etc., are able to produce thin fi lms of MS, they lack generality or need sophisticated instrumentation, and are complicated. In this context, chemical bath deposition is inarguably the simplest method for thin fi lm deposition. Generally, a suitable complexing agent and pH regulating agents are added in order to avoid spontaneous precipitation in an aqueous bath, which makes the process complicated due to extremely critical optimization for concentration of complexing agents and pH adjustment for an individual MS case. [ 4,[19][20][21][22] As a result, development of MS fi lms by solution-based method has often been a case of trial-and-error with poor reproducibility, which remained as an unexplored research fi eld yet in material science and technology. In order to tackle the above problems in aqueous solution, the fi lm deposition reaction is carried out in ethanol solution without the use of any complexing and/or pH-regulating agents. This protocol relies on dissolution of metal salts and thioacetamide in ethanol and heating the solutions at 70 °C. Although very few reports on MS fi lm deposition from nonaqueous solution has been reported, [ 23,24 ] no general protocol is available that can be applied overall to deposit all variety of MS thin fi lms under similar conditions with good reproducibility. The proposed protocol is extremely simple and general, which can lay simple guidelines to fabricate almost all types of metal sulfi des uniformly over all area of the substrate, provided that the corresponding metal salts are soluble in ethanol. The as-deposited MS fi lms are highly crystalline even without thermal treatment. Interestingly, the fi lms can be directly grown on variety of conducting as well as non-conducting substrates such as glass, plastic, fl uorine doped tin oxide (FTO), Ti-foil, carbon paper, Whatman fi lter paper, etc., which can be of great technological importance. As an example of potential application of these thin fi lms, we demonstrate the use of NiS fi lm deposited on fl exible plastic substrates as FTO-free dual-functioned (electronic support + electrocatalytic) counter electrode in dye-sensitized solar cells Revisiting Metal Sulfi de

Copper–Organic Framework Fabricated with CuS Nanoparticles: Synthesis, Electrical Conductivity, and Electrocatalytic Activities for Oxygen Reduction Reaction

“…Herein, we report for the first time, to the best of our knowledge, a method for fabricating various amounts of nano‐CuS in/on a 3D MOF, which gives rise to nano‐CuS( x wt %)@Cu‐BTC ( x =1.4, 5.3, 8.8, 28, and 56) and nano‐CuS(99 wt %) (Scheme ). The series of composites were prepared by a simple solution infiltration method, using Cu‐BTC as a sacrificial template and a EtOH solution of thioacetamide as the sulfide source with the control of the reaction time and temperature. There have been some reports of the synthesis of metal oxides using MOFs as sacrificial templates, but none of metal sulfide.…”

Counter electrodes in dye-sensitized solar cells

“…26). 515 The flexible DSSC with the NiS CE exhibited a high PCE of 9.50% (vs. 8.97% for the device with Pt CE). The Wu group deposited CoS and NiS on FTO by a simple electrodeposition method and the morphology of the films was tuned by adding different amounts of ammonia (shown in Fig.…”

Copper–Organic Framework Fabricated with CuS Nanoparticles: Synthesis, Electrical Conductivity, and Electrocatalytic Activities for Oxygen Reduction Reaction

“…Herein, we report for the first time,t ot he best of our knowledge,amethod for fabricating various amounts of nano-CuS in/on a3 DM OF,w hich gives rise to nano-CuS(x wt %)@Cu-BTC (x = 1.4, 5.3, 8.8, 28, and 56) and nano-CuS(99 wt %) (Scheme 1). Thes eries of composites were prepared by as imple solution infiltration method, using Cu-BTC as as acrificial template and aE tOH solution of thioacetamide as the sulfide source [35] with the control of the reaction time and temperature.T here have been some reports of the synthesis of metal oxides using MOFs as sacrificial templates, [36][37][38] but none of metal sulfide.Inmost of those cases,t emplate MOFs were completely consumed during the formation of the NPs,a nd only NPs and/or carbon was left. Thep resent solution infiltration method enables the amount of CuS formed in/on the MOF to be easily controllable.B yi ncreasing the amount of nano-CuS in the material, electrical conductivity increases by up to 10 9 -fold, while porosity decreases,c ompared to those of the pristine Cu-BTC.InORR, the catalytic performance of the composite materials significantly increases,asshown by increases in the onset voltage,e lectron transfer number,a nd kinetic current density,c ompared with those of the pristine MOF and nano-CuS.T his is due to the synergistic effect of two different materials,w hich provide the porosity and the electrical conductivity,respectively.Inthe present composite materials, nano-CuS(28 wt %)@Cu-BTC shows the best ORR activity.…”