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1、CdTe魔尺寸納米晶的合成及其生長(zhǎng)機(jī)理研究王坤,劉明洋,余啟鈺*,余睽(四川大學(xué)原子與分子物理研究所,四川成都610065)摘要:不同于半導(dǎo)體常規(guī)納米晶(RNCs),魔尺寸納米晶(MSNCs)由于其精確的結(jié)構(gòu)以及超窄的帶邊熒光發(fā)射引起了人們廣泛的關(guān)注。然而MSNCs的合成常為不同種類(lèi)的MSNCs和RNCs的摻雜混合,這使得高純度、單一尺寸的MSNCs的合成往往十分困難。本文以醋酸鎘和三辛基碲化膦為鎘前驅(qū)體和碲前驅(qū)體,長(zhǎng)鏈烷基酸為表面配體,利用高溫?zé)嶙⒌姆椒ㄔ?-十八烯中成功合成了兩種單一尺寸的CdTeMSNCs。實(shí)驗(yàn)結(jié)果表明,適當(dāng)鏈長(zhǎng)的配體
2、酸以及相對(duì)較低的酸量是抑制RNCs生長(zhǎng),合成單一尺寸的CdTeMSNCs的關(guān)鍵。反應(yīng)溫度則很大程度上決定了生成的MSNCs的尺寸。采用TEM、EDX、XPS和XRD分析了所合成的CdTeMSNCs的形貌、組成以及結(jié)構(gòu),結(jié)果顯示其呈現(xiàn)為均一的點(diǎn)狀形貌、且具有富鎘的纖鋅礦型結(jié)構(gòu)。通過(guò)對(duì)升溫處理過(guò)程中CdTeMSNCs所呈現(xiàn)出來(lái)的非連續(xù)生長(zhǎng)模式進(jìn)一步分析,提出了一種類(lèi)似Ostwaldripening的生長(zhǎng)機(jī)制,即部分的CdTeMSNCs在高溫下直接分解成單體,沉積在另一部分CdTeMSNCs上,使其“跳躍式”的生長(zhǎng)成了尺寸更大的MSNCs。關(guān)鍵詞
3、:碲化鎘;魔尺寸納米晶;高純度;生長(zhǎng)機(jī)理;有機(jī)酸中圖分類(lèi)號(hào):O611.4文獻(xiàn)標(biāo)志碼:A11TheStudyofCdTeMagic-SizeNanocrystalSynthesisandGrowthMechanismKunWang,MingyangLiu,QiyuYu,KuiYu(InstituteofAtomicandMolecularPhysics,SichuanUniv.,Chengdu610065,China)Abstract:Magic-sizenanocrystals(MSNCs)haverecentlyattractedmuch
4、attentionbecausetheyaremorestablecomparedtotheirsimilar-sizedcounterpartscalledregularnanocrystals(RNCs)duetotheirdefinedmolecularstructures.However,thesynthesisofMSNCsinpureformhasbeenacknowledgedtobechallengingsincethecoexistenceofdifferenttypesofMSNCsandRNCsisdifficultt
5、oavoid.Inthepresentstudy,CdTeMSNCswerepreparedfromcadmium-acetate/carboxylicacidandtri-n-octylphosphinetellurideinnon-coordinatingsolvent1-octadecene.ItwasgenerallyfoundthatonlywithsmallamountsofcarboxylicaciditispossibletoobtainMSNCsofhighpurity.Furthermore,twodifferentty
6、pesofCdTeMSNCsweresynthesizedbysimplyvaryingthereactiontemperature.TEM,HRTEM,XRD,EDXandXPSwereusedtoexaminethemorphology,compositionandcrystalstructureoftheas-preparedCdTeMSNCswhichexhibitadot-likemorphology,awurtzitestructureandaCd-richsurfacecomposition.Additionalexperim
7、entswereperformedtostudythegrowthmechanismofMSNCsusingUV-visabsorptionreal-timemonitoring.OurresultssuggestthatlargerMSNCsgrowhattheexpenseofsmalleronespartlydissolvingintomonomerwhichserveasgrowthmaterialsimilartoOstwaldripeningcommonlyobservedforRNCs.KeyWords:CdTe;magic-
8、sizenanocrystals;high-purity;growthmechanism;carboxylicacid11半導(dǎo)體魔尺寸納米晶(magic-sizenanocrys