Bi2Te3Bi2Se3纳米复合热电材料的制备和性能英文.docx

preparation and properties of bi2 te3 / bi2 se3 thermoelectricnanocomposite material sd u yong , l i hui , a n ba i2jun , cai ke2f eng( functional materials research la boratory , tongji university , shangha i 200092 , china)【abstract】 bi2 te3 a nd bi2 se3 na nopo w der s were p rep a re d by hydro t her mal synt he si s met ho d . af t erha vi ng bee n mi xed t he bi2 te3 a nd bi2 se3na nopo w de r s we re ho t p re sse d at 523 to 623 k a nd 50 o r 80m pa i nvacu um. the p ha se st r uct ure , mo rp holo gy , a nd co mpo sitio n of t he na nopo w der s a nd t he ho t p re sse d sa mp le swe re e xa mi ned by po w der x2ra y diff racto met r y , sca nni ng elect ro n micro scop y , fiel d e mi ssio n sca nni ng elect ro n micro scop y a nd e ner gy di sp er sive sp ect ro scop y , re sp ectivel y . the ca r rier co nce nt ratio n , mo bilit y , a nd hall coefficie nt of t he bul k sa mp le s we re mea sure d at roo m t e mp e rat ure . the elect rical co nductivit y a nd see bec k coefficie nt of t he bul k sa mp le s we re mea sure d f ro m roo m t e mp e rat ure up to 598 k. the sa mp le ho t p re ssed at623 k a nd 80 m pa fo r 60 mi n reac he s it s ma xi mu m po wer f acto r 19 . 1wc m - 1k- 2at 398 k. a nd t hei nf l ue nce of si nt e ri ng t e mp e rat ure a nd p re ssure o n t he p ha se st r uct ure a nd mo rp holo gy of t he sa mp le s wa sst udie d.【 key words】 bi2 te3 ; bi2 se3 ; t he r moelect ric p rop e rtie s ; p rep a ratio n ; co mpo sit eclc n umber : o482 . 6document code : abi2 te3 / bi2 se3 纳米复合热电材料的制备和性能杜永 ,李晖 ,安百俊 ,蔡克峰( 同济大学功能材料研究所 , 上海 200092)【摘要】 通过水热法分别合成了 bi2 te3 和 bi2 se3 纳米粉末 ,粉末按目标产物 bi2 te2 . 85 se0 . 15 混合后真空热压烧结 (523623 k ,50 或 80m pa) 制成块体材料 。用 x 射线衍射 ( xrd) 、扫描电镜 ( s em)和场发射扫描电镜对合成的粉末和块体进行了分析 ,对块体在室温附近的载流子浓度 、迁移率 、霍尔系 数 、以及 298598 k 温度区间的电导率和 see bec k 系数进行了测试 。在 623 k ,80 m pa ,保温 60 mi n 真空热压烧结得到的样品的功率因子在 298 k 达到了峰值 19 . 1wcm - 1 k- 2 。探讨了烧结温度和压力对材料相结构和形貌的影响 。【关键词】 碲化铋 ;硒化铋 ;热电性能 ;制备 ;复合材料t he po t e ntial to ma ke co nt ri butio n s to reduci ng1 int ro d uctio ngree nho u see ner gy 1 ,2 .ga se mi ssio n sa ndp ro vi degree n(t e )the r mo elect ricdevice shavebee nthe t e p e rfo r ma nce of a mat erial i s qua ntifie dby t he di me n sio nle ss fi gure of merit z t ( =2t/,at t racti ng mo re a nd mo re at t e ntio n beca u se t hey havereceived data : 2009210214 ; modif ied data : 2009212204foundation item : thi s wo r k wa s suppo rt ed by nat ural science fo undatio n of chi na ( 50872095) a nd 9732p roject ( 2007cb607500) .biogra phy : du yo ng , docto r st udent , explo re t he a rea of t her moelect ric i no r ga nic2o r ganic nanoco mpo sit e s , e2mail : duyo ng212 163 . co mcorresponding a uthor : ca i ke2f eng , e2mail : kf cai mail . to ngji . edu . cn .材料科学与工程学报252 2010 年 4 月w h e re i s t he see bec k co efficie nt , t he elect ricalco nductivit y , t he t he r mal co nductivit y , a nd t t heto t he fo r mula of bi2 te2 . 85 se0 . 15 i n a n a gat e mo r t a r .the mi xe d po w der s we re ho t p re ssed at 50 o r 80m pa fo r 60 mi n at diff e re nt si nt eri ng t e mp e rat ure s f ro m523 to 623 k unde r vac uum . the sa mp le s were na me d a s“ha2b”, w here“h”de no t e s ho t p re ssi ng ,“a”t he si nt eri ng t e mp erat ure a nd“b”t he p re ssure u se d.the p ha se st r uct ure of t he po w de r a nd ho t2p re ssed sa mp le s wa s e xa mi ne d by x2ray diff ractio n ( xrd , b r u ker d8 a dva nce ) , wit h cu k ra diatio n ( = 1 . 5406 ! ) . the f ract ure surf ace a nd t heco mpo sitio n of t he ho t p re ssed sa mp le s we ret e mp e rat ure ) .therefo re , a n i dealt e mat e rialsho ul d have la r ge see beck coefficie nt , la r ge elect ricalco nductivit y , a nd lo w t her mal co nductivit y.n2t yp e bi2 te3 2bi2 se3 mat e rial s a re co n sidere d to be t he be st mat e rial s u sed i n t e ref ri ge ratio n a ro und roo m t e mp erat ure . ma ny st udie s o n t he se mat erial s ha ve bee n p erfo r med i n o r der to i ncrea se t he z t val ue 3 ,4 . na no st r uct uri ng i s co n si dered to be o ne of t he mo st i mpo r t a nt app roache s to bul k t e mat erial s wit h hi gh z t val ue .up to no w , va rio u s t ech nique s a re develop e d too b se r vedbyfiel de mi ssio nsca nni ngelect ro nmicro scop y( f e2s em ,q ua nt a 200f e g )a ndna nopo w der s 5 ,(synt he sizesuchball a nda srapi dsca nni ngj sm5510 )elect ro nmicro scop ys em ,j eolsoli dificatio n 6 ,ato mizatio n 7 ,milli ng 8 , t he r mol y si swit ht he seequipp e dwit he ne r gydi sp e r sivesurf act a ntdi rect e dsynt he si s 9 sp ect ro met r y ( ed s o xfo r d 7582 ) .t he sa mp le s we re mea sured by met ho d .theho tp re ssedsa mp le sthe de n sitie s oft he a rchi me de smet ho d s 10 .reductio nco mp a redmet ho d s , hydro t her mal synt he si s met ho d ha s ma nya dva nt a ge s , suc h a s lo w co st a nd hi gh efficie ncy 11 , a nd it do e s no t requi re hi gh2p urit y raw mat erial s.the refo re , i n t hi s p ap e r , we hydro t her mal synt he size d bi2 te3 a nd bi2 se3 na nopo w de r s , a nd i n o r de r to ac hieve de n se sa mp le s at relativel y lo wt e mp e rat ure a s well a s keep fi ne micro st r uct ure , wewerec uti ntofo rtherect a ngula r piece s ( 10 mm 1 mm 2 mm )elect ricalt ra n spo r tp rop er t ymea sure me nt .see bec k co efficie nt wa s det er mi ne d by t he slop e oft heli nea rrelatio n shipbet wee nt het her moelect ro mo tive fo rce a nd t e mp e rat ure diff ere nce( 10 k ) bet wee n t he t wo e nds of t he sa mp le . elect rical co nductivit y mea sure me nt wa s p e rfo r me du si ng a st ea dy2st at e fo ur2p ro be t ech nique wit h a squa re wave cur re nt (10 ma i n a mp lit ude) .the hall co efficie nt , mo bilit y , a nd ca r rier co nce nt ratio n of t he sa mp le s we re mea sure d u si ng h m s23000 ( ecopia ) at roo m t e mp erat ure wit h ama gnetic fiel d of 0 . 55 t.mi xed t he na nopo w der s a nd t he n ho tna nopo w der s under vacu um.p re ssedt he2 exp e ri me nt alall c he mical rea ge nt s u se d weregra de .of a nal yticalfo r p rep a ri ng bi2 te3 ( bi2 se3 ) na nopo w der s ,a bo ut 60 ml deio nized wat er wa s a dded i nto a tef lo n23re s ul t s a nd di sc u s sio nli ne d 100 mla utoclave .app rop riat ea mo u ntofbi ( n o3 ) 3 5 h2 o , c4 h4 na2 o6 2 h2 o , teo2 ( se) ,ko h a nd kb h4 were p ut i nto t he a utoclave seque ntiall y , a nd t he n so me deio nized wat e r wa s a dde d until 80 % of t he vol ume of t he a utocla ve wa s filled . the a utoclave wa s sealed a nd mai nt ai ned at180 fo r 24 h a nd t he n nat urall y cooled to roo mt e mp e rat ure . the p ro duct wa s wa shed wit h deio nize d wat er a nd p ure et ha nol i n seque nce fo r several ti me s t he n filt ered . fi nall y t he da r k p ro duct wa s drie d i n vacu um.bi2 te3 a nd bi2 se3 po w der s were mi xe d acco r di ngthe de n sit y of t he h523250 , h523280 , h573280h598280 , h623280 sa mp le s i s 5 . 220 , 5 . 601 , 5 . 806 ,6 . 625 a nd 7 . 328g c m - 3 re sp ectivel y , a nd t he po ro sit y of t he sa mp le s i s 32 . 6 % , 27 . 6 % , 25 . 0 % ,14 . 4 % a nd 5 . 40 % re sp ectivel y. thi s i ndicat e s t hatt he de n sit y of t he sa mp le i ncrea se wit h t he si nt e ri ngt e mp erat urea ndt hep re ssure .thesi nt e ri ngt e mp erat ure belo w 598 k i s no t hi gh e no ugh .fig . 1 sho w s t he xrd p at t e r n s ofbi2 se3a ndbi2 te3 na nopo w de r s p rep a re d.all t he xrd p ea k s i n 1994-2013 china academic journal electronic publishing house. all rights reserved. 第 28 卷第 2 期杜永 ,等 . bi2 te3 / bi2 se3 纳米复合热电材料的制备和性能253 fi g. 1 (a) a nd ( b) ca n be i nde xe d to t he r ho mbo hedrala s t he si nt e ri ng t e mp e rat ure i ncrea se s , t he grai n s i nt he sa mp le s gro w up a nd t he cr yst alli ne of t he grai n s i s bet t e r .bi2 se3( j c pd sca r dfile ,no3320214 )a ndr ho mbo hedral bi2 te3 (j cpd s ca r d file , no 1520863) ,re sp ectivel y , a nd bo t h wit h sp ace gro up : r23 m(166 ) . no i mp urit y p ea k s a re o b se r ved , i ndicati ng t he p rep a red na nopo w der s wit h hi gh p urit y .fig . 1 xrd p at t er n s of t he hydro t her mal synt he sized ( a) bi 2 se3a nd ( b) bi 2 te3 na nopo wder sba sed o n scher rer s fo r mula l = k/ ( co s )(l i s t he grai n size , k a co n st a nt , t he x2ra y wa vele ngt h , t he half wi dt h of t he diff ractio np ea k) , t he a ve ra ge grai n size of t he bi2 se3 a nd bi2 te3na nopo w der s a re e sti mat e d to be a bo ut 11 nm a nd48 nm.fi gs. 2 ( a ) a nd 2 ( b) sho w t he xrd p at t e r n s of t he bul k sa mp le s ho t p re ssed at 523 k wit h diff e re nt p re ssure s a nd ho t p re ssed at 80 m pa wit h diff e re nt si nt eri ng t e mp erat ure s , re sp ectivel y. it ca n be see n f ro m fi g . 2a a nd fi g. 2 b t hat all t he xrd p ea k s of t hesa mp le s e xcep t a wea k p ea k at 30 . 9fo r t he h6232fig . 2 ( a) xrd p at t er ns of t he ( a)h523250 a nd ( b) h523280sa mple s ; ( b) xrd p at t er ns of t he ( a) h523280 , ( b) h573280 ,(c) h598280 a nd ( d) h623280 sa mple sta ble 1 give s t he see beck coefficie nt , elect ricalco nductivit y , ca r rier co nce nt ratio n , mo bilit y a nd hall co efficie nt of t he sa mp le s at roo m t e mp erat ure . it ca n be see n f ro m t a ble 1 t hat a s t he si nt e ri ngt e mp erat ure i ncrea se s f ro m 523toelect rical co nductivit y of t he sa mp le i ncrea se s f ro m 6 . 983 to 715 . 5 s/ cm ,623 k , t hedra maticall y w he rea s t he80sa mp leco r re spo ndtot heref lectio n sofa b sol ut echa nged .see beck coefficie nt val ue s a re no t muc hthe elect rical co nductivit y of t he h623280r ho mbo hedral bi2 te3 (j cpd s ca r d file , no 1520863) .the wea k p ea k i n t he xrd p at t er n fo r t he h623280 sa mp le co r re spo nd s to bi2 se3 . thi s i ndicat e s t hat bi2 se3 a nd bi2 te3 i n all t he sa mp le s e xcep t t he h623280 react each o t he r to fo r m si ngle p ha se sa mp le s duri ng t he ho t p re ssi ng. ed s a nal ysi s of t he h598280 sa mp le reveal s t hat t he sa mp le co nt ai n s bi , te a nd sewit h a n ato mic ratio of bi te se = 2 2 . 93 0 . 08 , 8 sa mp le i s la r ger t ha n t he re sult repo r t ed i n ref . (415 s/ cm) .s em i ma ge s of t he f ract ure surf ace of t hesa mp le s ho t p re ssed at 80m pa a re sho w n i n fi g . 3 ( t he mo rp holo gy of t he h523250 sa mp le i s si mila r to fi g. 3 ( a ) ) . it ca n be see n f ro m fig . 3 t hat t he micro st r uct ure of all t he sa mp le s i s ho mo ge neo u s a nd fi ne , a nd t hat t he sa mp le s beco me de n ser a s t he si nt eri ng t e mp erat ure i ncrea se s. thi s a gree s wit h t he de n sit y mea sure me nt re sult s. a s t he grai n size s oft he sa mp le s a re too fi ne to be clea rl y o b ser ve d unders em . the sa mp le s we re f ur t he r o b ser ve d underf s em . a s a n e xa mp le , fi g s. 3 ( e) a nd (f ) sho w t hew hichdeviat e sso mew hatf ro mt heno mi nalco mpo sitio n . thi s i ndicat e s t he sa mp le s a re te rich .the rea so n fo r t he h623280bi2 se3 p ha se i s no t clea r yet .it ca n be al so see n f ro msa mp lestillhavi ngfi g. 2 bt hatxrda s t hep ea k ssi nt eri ng t e mp erat ure i ncrea se s , t hebeco me sha rp e r a nd st ro nge r . thi s sho ul d be beca u se 1994-2013 china academic journal electronic publishing house. all rights reserved. 材料科学与工程学报254 2010 年 4 月f ract ure surf ace f s em i ma ge s of t he sa mp le h573280sa mp le loo k s no t well si nt e re d. by co mp a ri ng fi g. 3(e) wit h fi g. 3 (f ) , it i s see n t hat t he sa mp le h623280 ha s bi gger grai n size s ( 100 to 800 nm) a nd t hat t he sa mp le i s de n se r .a nd h623280 , re sp ectivel y . itf ro m fi g. 3 ( e ) t hat t he grai nca n be clea rl y see nsize s of t he sa mp leh573280 a re i n t he ra nge of 100 to 500 nm . theroom temperature seebeck coeff icient() , electrical conductivity() , carrier concentration ( n) ,mobil ity (h ) and hall coeff icient ( rh ) of the sa mplesta ble 1h / ( cm2 v - 1 s - 1 )r h / cm3 c - 1sa mple/v k - 1/ s cm - 1n/ cm - 3h523280h573280h623280- 121 . 546 . 983 e + 008 . 321 e + 185 . 239 e + 00- 7 . 502 e201- 3 . 425 e201- 3 . 709 e204- 173 . 735 . 119 e + 011 . 822 e + 191 . 754 e + 012 . 6545 e201- 153 . 787 . 155 e + 021 . 945 e + 22fig. 3 sem i mage s of t he f ract ure surf ace s of ( a)h523280 , ( b) h573280 , (c) h598280 , ( d)h623280 ,and f es em i mage s of ( e) h573280 , (f ) h623280 sa mple sthe elect rical co nductivit y i s give n by t heco nductio n , w hich a gree swit h t hehalleff ectfollo wi ng equatio n =co nce nt ratio n , e i s t heneh ,w here n i s ca r riermea sure me nt a nd t he re sult s repo r t ed i n ref s. 4 ,12 ,13 , but i s co nt ra r y to t he re sult s repo rt e d i n ref . 14 . a s t he t e mp e rat ure i ncrea se s , t he elect rical co nductivit y fi r st slo wl y decrea se s a nd t he n i ncrea se s gra duall y , w hile t he t e mp e rat ure dep e nde nce of a b sol ut e see bec k coefficie nt i s ro ughl y oppo sit e to t hat of t he elect rical co nductivit y . a s fig . 4 ( b ) sho w s , w he n t 400 k , t he po we r f acto r slo wl y i ncrea se s , t he n decrea se s quickl y w he n 400 t 450 k , it i ncrea se s wit h t he t e mp erat ure i ncrea si ng . a ma xi mum po wer f acto rreache s 19 . 1wc m - 1 k- 2 at 398 k w hic h i s lo wert ha n t he re sult repo r t ed i n ref . 8 ( 22 . 0wc m - 1k- 2 at roo m t e mp e rat ure ) . b ut a s we ca n see f ro m t he s em i ma ge ( fi g. 3f ) , t he sa mp le p rep a re d ha s fi ne micro st r uct ure ( na no st r uct ured ) , lo w t her malco nductivit y ca n be e xp ect e d due to a st ro ng grai ncha r ge , hi s t he ca r riermo bilit y. a s t he si nt eri ng t e mp erat ure i ncrea se s , t heca r rier co nce nt ratio n of t he sa mp le s i ncrea se s w hile t he ca r rie r mo bilit y fir st i ncrea se s t he n decrea se s seet a ble 1 , but t he ca r rie r co nce nt ratio n i ncrea se s mo resi gnifica nt l y , t heelect ricalco nductivit y ofsa mp le s dra maticall y i ncrea se s.in a dditio n , sa mp le si nt e re d at hi gher t e mp erat ure wit ht het he lo wpo ro sit y i sal soarea so nfo rhi ghelect ricalco nductivit y.fi g. 4 ( a )dep e nde nceofa nd ( b )sho w t he t e mp erat ureelect ricalco nductivit y ,see bec kcoefficie nt a nd po we r f acto r of t he h623280 sa mp le .it ca n be see n f ro m fi g. 4 ( a ) t hat t he see bec k coefficie nt of t he sa mp le i s ne gative i n all t het e mp e rat urera ngemea sured ,i ndicati ngn2t yp e 1994-2013 china academic journal electronic publishing house. all rights reserved. 第 28 卷第 2 期杜永 ,等 . bi2 te3 / bi2 se3 纳米复合热电材料的制备和性能255 bo u nda r y scat t e ri ng to p ho no n s ; he nce ,val ue fo r t he sa mp le ca n be e xp ect e d.ahi ghz t398 k.thi s p rep a ratio nco mpo sit e si slo w2co st , p ro mi si ng.ro ut e to bi2 te3 ba se dhi ghefficie ncy ,a ndref erences 1 l . d. zhao , b . p. zha ng , w. s. li u ,j . f. li . j . j . appl . phys. , 2009 , 105 , 6 .t. j . hendricks a nd n . k. ka r ri . c . i n 27t h int er natio nalco nf erence o n ther moelect rics , sp ri nger , co r valli s , o r , 2008 , pp . 12571267 .h . ko se , m . bicer , c. tut uno gl u , a . o . aydi n , i. si sma n . j . elect rochi m. act a , 2009 , 54 , 16801686 .s. j . ho ng , y. s. l ee , j . w. byeo n , b . s. chun . j . j . allo y . co mp d . , 2006 , 414 , 146151 .y. q . cao , t. j . zhu , x. b . zhao , x. b . zha ng , j . p. tu . j . appl . phys. a2mat er . sci . proce ss. , 2008 , 92 , 321 324 .t. s. ki m , i. s. ki m , t. k. ki m , s. j . ho ng , b . s. chun . j . mat er . sci . eng . b2soli d st at e mat er . a dv. technol . ,2002 , 90 , 4246 .k. ya nagi mo to , k. maji ma , s. sunada , t. sawada . j . j . allo y . co mp d . , 2004 , 377 , 174178 .j . y. ya ng , t. aizawa , a . ya ma moto , t. o ht a . j . j . allo y . co mp d . , 2000 , 312 , 326330 .a . pur ka