Molybdenum trioxide (MoO3) muaj peev xwm ua ib qho tseem ceeb ntawm ob sab (2-D) cov khoom, tab sis nws cov khoom siv ntau tau lagged qab ntawm lwm tus hauv nws chav kawm. Tam sim no, cov kws tshawb fawb ntawm A * STAR tau tsim ib txoj hauv kev yooj yim rau kev tsim cov khoom siv ultrathin, zoo MoO3 nanosheets.

Tom qab qhov kev tshawb pom ntawm graphene, lwm yam 2-D cov ntaub ntawv xws li kev hloov pauv hlau di-chalcogenides, tau pib nyiam ntau yam. Tshwj xeeb, MoO3 tau tshwm sim los ua ib qho tseem ceeb ntawm 2-D semiconducting khoom vim nws cov khoom siv hluav taws xob zoo tshaj plaws thiab kho qhov muag uas tuav cov lus cog tseg rau ntau yam kev siv tshiab hauv electronics, optoelectronics thiab electrochromics.

Liu Hongfei thiab cov npoj yaig los ntawm A * STAR Institute of Materials Research thiab Engineering thiab Lub Tsev Haujlwm Saib Xyuas Kev Ua Haujlwm Siab Siab tau nrhiav kev tsim cov txheej txheem yooj yim rau kev tsim cov khoom loj, zoo nanosheets ntawm MoO3 uas hloov tau thiab pob tshab.

Liu hais tias "Atomically nyias nanosheets ntawm molybdenum trioxide muaj cov khoom tshiab uas tuaj yeem siv rau hauv ntau yam kev siv hluav taws xob," Liu hais. "Tab sis los tsim cov nanosheets zoo, cov niam txiv siv lead ua yuav tsum yog cov purity siab heev."

Los ntawm thawj zaug siv cov txheej txheem hu ua thermal vapor thauj, cov kws tshawb fawb tau evaporated MoO3 hmoov nyob rau hauv ib lub raj-rooj cua sov ntawm 1,000 degrees Celsius. Tom qab ntawd, los ntawm kev txo tus naj npawb ntawm cov chaw nucleation, lawv tuaj yeem ua kom zoo dua cov thermodynamic crystallization ntawm MoO3 los tsim cov muaju zoo ntawm 600 degrees Celsius yam tsis tas yuav tsum muaj cov txheej txheem tshwj xeeb.

"Feem ntau, siv lead ua kev loj hlob ntawm qhov kub siab yog cuam tshuam los ntawm substrate," Liu piav qhia. "Txawm li cas los xij, yog tias tsis muaj lub siab xav ua rau peb muaj peev xwm tswj tau qhov kev loj hlob ntawm cov siv lead ua zoo dua, cia peb loj hlob molybdenum trioxide crystals ntawm siab purity thiab zoo."

Tom qab txias cov crystals rau hauv chav tsev kub, cov kws tshawb fawb tau siv cov khoom siv thiab cov aqueous exfoliation los tsim submicron-thick siv ntawm MoO3 crystals. Thaum lawv muab cov hlua khi rau sonication thiab centrifugation, lawv muaj peev xwm tsim tau cov ntawv loj, zoo MoO3 nanosheets.

Kev ua haujlwm tau muab kev nkag siab tshiab rau hauv kev sib cuam tshuam hauv hluav taws xob ntawm 2-D MoO3 nanosheets. Cov siv lead ua kev loj hlob thiab exfoliation cov tswv yim tsim los ntawm pab pawg kuj tseem tuaj yeem pab tau hauv kev tswj hwm qhov sib txawv-thiab yog li cov khoom siv hluav taws xob-ntawm 2-D cov ntaub ntawv los ntawm kev tsim 2-D heterojunctions.

Liu hais tias "Tam sim no peb tab tom sim tsim 2-D MoO3 nanosheets nrog thaj chaw loj dua, nrog rau kev tshawb nrhiav lawv cov peev txheej siv hauv lwm yam khoom siv, xws li cov ntsuas roj," Liu hais.