Organic Small Molecule Covalently Functionalized Molybdenum Disulfide Hybrid Material for Optical Limiting

Abstract

Abstract Molybdenum disulfide (MoS2) nanosheets are insoluble in any organic solvent, which makes them more difficult to fabricate into thin film devices for nanoelectronics and nonlinear optics. To solve practical solution-processability problems of the MoS2 nanosheets, it would be ideal and feasible to design and synthesize MoS2-based solution-processed organic/polymeric materials. In this work, new organic small molecule covalently modified MoS2 nanosheets (MoS2-CHT) were synthesized through a simple reaction between MoS2 and 6-(9H-carbazol-9-yl)hexane-1-thiol (CHT). Both a DMF solution of MoS2-CHT and a MoS2-CHT/PMMA film exhibited excellent nonlinear optical (NLO) and optical limiting (OL) responses when compared to the MoS2 and MoS2/CHT mixture. As a result, among these materials, the annealed MoS2-CHT/PMMA film showed the largest nonlinear absorption coefficients (βeff) and highest imaginary third-order susceptibilities (Imχ(3)) (997.75 cm/GW and 4.25 × 10−10 esu at 532 nm; 372.62 cm/GW and 3.19 × 10−10 esu at 1064 nm). The enhanced NLO/OL performance of the annealed film could be due to the structural transition of MoS2 in MoS2-CHT from the 1T phase to the 2H phase during the annealing and the possible thermal-induced electron transfer effect between MoS2 and CHT moieties in MoS2-CHT.