Dab tsi yog quantum dot zaub (QLED)?

Dab tsi yog quantum dots?

1.1 Lub tswv yim

Quantum dots yog semiconductor nanostructures uas khi excitons nyob rau hauv peb spatial cov lus qhia. Quantum dots yog ib qho tseem ceeb ntawm cov khoom siv semiconductor tsawg, thiab lawv qhov loj me yog tsis ntau tshaj ob zaug ntawm exciton Bohr radius (1-10nm) ntawm cov khoom siv semiconductor.

Quantum dots feem ntau yog spherical los yog quasi-spherical, thiab lawv txoj kab uas hla yog feem ntau ntawm 2-20 nm, thaum lub cheeb ntawm peb cov plaub hau yog txog 100,000 nm (100 μm).

1.2 Nta

Quantum dots yog nano-theem semiconductors. Los ntawm kev siv qee qhov hluav taws xob los yog lub teeb siab rau cov khoom siv nano-semiconductor, lawv yuav tawm lub teeb ntawm ib zaus, thiab qhov zaus ntawm lub teeb tawm yuav hloov nrog qhov loj ntawm qhov semiconductor. Yog li ntawd, los ntawm kev kho qhov loj ntawm no nano-semiconductor, cov xim ntawm lub teeb emission tuaj yeem tswj tau. Vim hais tias cov nano-semiconductor no muaj cov yam ntxwv ntawm kev txwv cov electrons thiab electron qhov (Electron qhov), cov yam ntxwv no zoo ib yam li atoms lossis molecules nyob rau hauv cov xwm. , Yog li hu ua quantum dots.

Quantum dots yog semiconductor nanocrystals. Thaum lawv qhov me me me dua li Bohr vojvoog ntawm exciton, qhov nruab nrab ntawm txoj kev dawb ntawm cov hluav taws xob raug txwv rau ib qho me me, thiab nws yooj yim los tsim cov exciton khub nrog qhov. Cov nthwv dej ua haujlwm ntawm cov hluav taws xob thiab qhov sib tshooj, uas ua rau muaj qhov nqus dej ntawm exciton. Qhov me me ntawm qhov quantum dot, qhov ntau dua qhov tshwm sim ntawm kev tsim excitons thiab siab dua qhov concentration ntawm excitons. Cov nyhuv no yog hu ua quantum confinement effect. Lub quantum confinement nyhuv ntawm quantum dots ua rau nws qhov kev ua tau zoo ntawm qhov sib txawv ntawm cov khoom siv semiconductor. Nws lub zog band qauv tsim ib co exciton zog theem nyob ze rau hauv qab ntawm lub conduction band, ua rau exciton absorption bands, thiab cov recombination ntawm excitons yuav tsim hluav taws xob fluorescence. Qhov loj ntawm quantum dots yog txawv, qhov degree ntawm electrons thiab qhov yog quantum confined yog txawv, thiab lawv discrete zog theem qauv kuj txawv.

Raws li qhov loj me me zuj zus, qhov kev txwv ntawm electrons thiab qhov nce, ua rau muaj kev nce hauv lub zog kinetic ntawm ob, uas yog, nce hauv quantum confinement zog, thiab qhov zoo ntawm qhov sib txawv ntawm quantum dot widens, thiab Qhov sib thooj nqus thiab emission spectra tshwm sim Xiav hloov, thiab qhov me me, qhov ntau dua qhov xiav hloov. Yog li ntawd, los ntawm kev kho qhov loj ntawm quantum dots, emission spectrum ntawm quantum dots tuaj yeem hloov kho.

Lub zog theem ntawm quantum dot yog sib cais vim quantum confinement nyhuv, thiab semiconductor band sib txawv nce raws li qhov loj ntawm nanocrystal txo.

Cov khoom tseem ceeb ntawm quantum dots

1.3 Kev npaj

1.3.1 Cov ntaub ntawv

Feem ntau quantum dots yog tsim los ntawm IV, II-VI, IV-VI lossis III-V cov ntsiab lus. Cov piv txwv tshwj xeeb yog silicon quantum dots, germanium quantum dots, cadmium sulfide quantum dots, cadmium selenide quantum dots, cadmium telluride quantum dots, zinc selenide quantum dots, lead sulfide quantum dots, lead selenide quantum dots, lead selenide quantum dots, zinc selenide quantum dots, lead sulfide quantum dots, lead selenide quantum dots dots, lwm.

Tam sim no siv quantum dot cov ntaub ntawv feem ntau suav nrog cadmium selenide (CdSe) series thiab indium phosphide (InP) series. Lub qub yog siv los ntawm QD Vision, tom kawg yog siv los ntawm Nanoco, thiab Nanosys siv indium phosphide thiab cadmium hybrid quantum dots. npaj. Ob hom quantum dots muaj lawv tus kheej qhov zoo thiab qhov tsis zoo. Cadmium selenide yog qhov zoo dua li kev ua haujlwm siab luminous thiab dav xim gamut. Indium phosphide tsis muaj cadmium thiab tsis txwv los ntawm EU ROHS tus qauv.

1.3.2 Txoj kev npaj

Kev tsim cov txheej txheem ntawm quantum dots tuaj yeem muab faib ua peb pawg: chemical solution txoj kev loj hlob, txoj kev loj hlob ntawm epitaxial, thiab txoj kev kaw hluav taws xob. Peb hom kev tsim khoom no kuj sib xws rau peb hom quantum dots.

Tshuaj daws kev loj hlob

Xyoo 1993, pab pawg tshawb fawb coj los ntawm xibfwb Bawendi ntawm Massachusetts Institute of Technology tau tsim cov quantum dots ntawm cov xim sib xws hauv cov tshuaj organic rau thawj zaug. Lawv yaj peb cov pa oxygen (sulfur, selenium, thiab tellurium) hauv tri-n-octyl phosphine oxide, thiab tom qab ntawd ua rau dimethyl cadmium hauv cov organic tov ntawm 200 mus rau 300 degrees Celsius los tsim cov khoom siv quantum dot (cadmium sulfide). , cadmium selenide, cadmium telluride). Tom qab ntawd, tib neeg tau tsim ntau txoj hauv kev los tsim cov colloidal quantum dots raws li txoj kev no. Feem ntau cov ntaub ntawv semiconductor tuaj yeem raug tsim los ntawm cov tshuaj lom neeg txoj kev loj hlob los tsim cov quantum dots sib xws.

Colloidal quantum dots muaj qhov zoo ntawm cov nqi qis, siab yield, thiab siab luminous efficiency (tshwj xeeb tshaj yog nyob rau hauv cov pom thiab ultraviolet bands). Tab sis qhov tsis zoo yog tias cov conductivity tsawg heev. Txij li cov organic ligands yog tsim nyob rau saum npoo ntawm quantum dots thaum lub sij hawm tsim cov txheej txheem, van der Waals attraction ntawm quantum dots yog offset los tswj nws stability nyob rau hauv cov tshuaj. Tab sis txheej txheej ntawm cov organic ligands zoo heev cuam tshuam kev hloov pauv ntawm cov nqi ntawm quantum dots. Qhov no zoo heev txo cov ntawv thov ntawm nanocrystals hauv lub hnub ci hlwb thiab lwm yam khoom. Cov kws tshawb fawb tau sim ntau txoj hauv kev los ua kom cov khoom siv hluav taws xob ntau ntxiv hauv cov khoom siv no. Sawv cev, xyoo 2003, Xib Fwb Guyot-Sionnest ntawm University of Chicago tau hloov qhov qub-chain organic ligands nrog luv-chain amino tebchaw, nqaim lub quantum dot spacing, thiab txhaj ib tug loj tus naj npawb ntawm electrons rau hauv quantum dots los ntawm electrochemical txoj kev. Sab hauv, cov conductivity yog nce mus rau 0.01S / cm.

Kev loj hlob ntawm epitaxial

Txoj kev loj hlob epitaxial yog hais txog kev loj hlob ntawm cov muaju tshiab ntawm cov khoom siv substrate. Yog tias cov crystals me me, quantum dots yuav tsim. Raws li qhov sib txawv ntawm txoj kev loj hlob, txoj kev no tuaj yeem muab faib ua cov tshuaj vapor deposition thiab molecular beam epitaxy.

Cov quantum dots zus los ntawm txoj kev no loj hlob ntawm lwm hom semiconductor thiab tau yooj yim ua ke nrog cov khoom siv semiconductor. Tsis tas li ntawd, vim tias tsis muaj cov organic ligands, tus nqi hloov pauv ntawm epitaxial quantum dots yog siab dua li ntawm colloidal quantum dots, thiab lub zog theem tswj tau yooj yim dua li colloidal quantum dots. Nyob rau tib lub sijhawm, nws kuj muaj qhov zoo ntawm qhov tsis zoo ntawm qhov chaw tsawg. Txawm li cas los xij, txij li ob qho tib si tshuaj vapor deposition thiab molecular beam epitaxy xav tau lub tshuab nqus tsev siab lossis ultra-high nqus, tus nqi ntawm epitaxial quantum dots yog siab dua li ntawm colloidal quantum dots.

Electric teb confinement txoj kev

Txoj kev kaw hluav taws xob yog hais txog kev siv tag nrho ntawm lub peev xwm ntawm cov hlau electrode kom distort lub zog theem nyob rau hauv lub semiconductor los tsim ib qho kev txwv ntawm cov nqa khoom. Txij li qhov yuav tsum tau loj ntawm quantum dots yog nyob rau theem nanometer, cov hlau electrode yuav tsum tau fabricated los ntawm electron beam raug. Tus nqi yog qhov siab tshaj plaws thiab qhov tawm los yog qhov qis tshaj. Txawm li cas los xij, quantum dots uas tsim los ntawm txoj kev no tuaj yeem tswj hwm lawv cov qib zog, tus naj npawb ntawm cov cab kuj thiab tig yooj yim los ntawm kev kho lub rooj vag voltage. Vim muaj kev tswj xyuas siab heev, xws li quantum dots kuj zoo tshaj plaws rau quantum xam.

1.4 Kev siv quantum dots

02

Kev siv quantum dot zaub

2.1 Keeb kwm

Nyob rau hauv thaum ntxov 1970s, vim txoj kev loj hlob ntawm semiconductor epitaxial txoj kev loj hlob technology, kev npaj ntawm nanostructures tau ua. Ua ntej ntawm tag nrho cov, nyias-txheej ob-dimensional nanostructures hu ua Quantum Wells (QW) tau tsim thiab kawm ntau heev. Qhov no nano-thin txheej txheej yog tsim los ntawm kev npaj ntawm ob yam khoom semiconductor. Cov electrons thiab qhov yog nyob rau hauv ib tug nyias txheej ntawm ob peb nanometers tuab, uas muaj pom tseeb confinement nyhuv. Los ntawm kev kho qhov muaj pes tsawg leeg, qhov sib txawv band ntawm quantum zoo tuaj yeem hloov pauv.

Nyob rau hauv 2011, Samsung Electronics tsim quantum dot teeb-emitting diodes siv organic thiab inorganic txheej raws li cov electron thiab lub qhov thauj khaubncaws sab nraud povtseg ntawm lub quantum dot teeb-emitting txheej, feem. Los ntawm kev ua qauv ntawm quantum dot zaj duab xis los ntawm txoj kev hloov mus, Samsung Electronics tau tsim 4-nti puv xim matrix QLED zaub ntaus ntawv qauv. Samsung cov kws tshawb fawb thawj zaug siv cov tshuaj quantum dot rau ntawm lub phaj silicon, tom qab ntawd evaporate, thiab tom qab ntawd nias qhov protruding rau hauv quantum dot txheej. Tom qab tshem tawm cov txheej txheej saum npoo, nws raug xa mus rau iav substrate lossis yas substrate. Cov txheej txheem no paub qhov quantum dot rau lub substrate. Hloov. Nws cov kws tshawb fawb tau hais tias cov iav substrates los yog hloov tau yooj yim yas substrates tau siv los ua kom tiav cov khoom tsim qauv.

Txij li xyoo 2013, quantum dot zaub technology tau siv rau cov kua siv lead ua kua (LCD) panels. Lub quantum dot zaj duab xis yog sib sau ua ke ntawm lub teeb pom kev zoo thiab cov kua siv lead ua kua cell thiab siv rau cov xim gamut TVs thiab cov ntsiav tshuaj computers kom ua tiav ntau yam xim. Domain thiab qis zog noj.

Sony launched ib tug high-end LCD TV qauv uas siv quantum dot technology nyob rau hauv lub backlight nyob rau hauv Lub rau hli ntuj 2013; Amazon kuj tau tshaj tawm lub khoos phis tawj ntsiav tshuaj uas siv quantum dots hauv LCD backlight thaum Lub Kaum Hli 2013.

2.2 Qhia cov yam ntxwv ntawm quantum dots

1. High xim purity, nqaim emission spectrum ncov thiab symmetrical tis;

2. Lub emission spectrum yog adjustable, thiab emission wavelength hloov tau los ntawm kev tswj qhov loj thiab cov khoom ntawm quantum dots, yog li tswj lub teeb-emitting xim;

3. Kev ua tau zoo xim, npog xim gamut ntau dua 100% NTSC;

4. Lub luminous efficiency yog siab, lub quantum efficiency siab li 90%, thiab lub teeb stability yog zoo;

5. Nws muaj peev xwm paub txog nano-theem pixels, uas tuaj yeem siv los tsim cov ntxaij vab tshaus ultra-high-resolution.