國立虎尾科技大學 |

Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells = = Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells =/
Reminder of title:	Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar.
Author:	Baruj, Hamed Dehghanpour.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2022,
Description:	107 p.
Notes:	Source: Masters Abstracts International, Volume: 84-05.
Contained By:	Masters Abstracts International84-05.
Subject:	Tin. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29469866
ISBN:	9798352968802

Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells = = Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar.
Baruj, Hamed Dehghanpour.

Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells =Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar. - Ann Arbor : ProQuest Dissertations & Theses, 2022 - 107 p.

Source: Masters Abstracts International, Volume: 84-05.

Thesis (M.Sc.)--Bilkent Universitesi (Turkey), 2022.

This item must not be sold to any third party vendors.

Semiconductor colloidal quantum wells (CQWs) make an exciting quasi-2D class of nanocrystals thanks to their unique properties emerging from their atomically-flat verticallythin geometry including highly anisotropic optical transition dipole moment (TDM), giant oscillator strength, and extraordinarily high absorption cross-section. This regular shape of the CQWs enables them to assemble on the surface of a liquid with a high degree of packing, which creates an almost fully uniform monolayer film with the desired orientation. Nearly all of the emission in a single CQW, again because of its geometry, comes from in-plane (IP) transition dipole moments (TDMs). Thus, an assembled film of such CQWs with an all-facedown orientation may show a highly anisotropic and directional emission. Using such a film in an emissive layer (EML) of an electroluminescent device, in this thesis work our intention is therefore to substantially boost photon outcoupling efficiency in a light-emitting device of oriented monolayer of CQWs. Thus far, research efforts have been conducted to investigate the properties of the deposited film of CQWs with self-assembly. However, in all of the previous studies, the property of CQW monolayer has been investigated only in a passive film; therefore, investigation of the self-assembled film in an active device is lacking. In this thesis, we developed and demonstrated an all-solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) using a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that enables a high level of IP TDMs of 92%. This film significantly enhances the outcoupling efficiency of LEDs from 22% (of standard randomlyoriented emitters) to 34% (of face-down oriented emitters). As a result of the outcoupling efficiency increased by 1.55 times, along with the enhanced charge injection and reduced reabsorption in the case of using a single SAM of CQWs, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with those of the hybrid organic-inorganic evaporationbased CQW-LEDs and all other best solution-processed LEDs. This EQE value is 65% higher than that in the devices fabricated by spin-coating with the same procedure and structure. Also, the SAM-CQW-LED architecture enables a high maximum brightness of 19,800 cd/m2 with a long operational lifetime of 247 h at 100 cd/m2 , as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV and a high J90 of 99.58 mA/cm2 . These findings indicate the effectiveness of oriented self-assembly of CQWs as electrically-driven emissive layers in improving outcoupling and external quantum efficiencies in the CQW-LEDs.

ISBN: 9798352968802Subjects--Topical Terms:

1413632
Tin.

Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells = = Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar.
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100 1 $a Baruj, Hamed Dehghanpour. $3 1413630
245 1 0 $a Solution-Processed Light-Emitting Diodes of Monolayers of Colloidal Quantum Wells = $b Koloidal Kuantum Kuyularinin Tekli Katmanlarini Iceren Cozelti-Bazli Isik Yayan Diyotlar.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2022
300 $a 107 p.
500 $a Source: Masters Abstracts International, Volume: 84-05.
500 $a Advisor: Demir, Hilmi Volkan.
502 $a Thesis (M.Sc.)--Bilkent Universitesi (Turkey), 2022.
506 $a This item must not be sold to any third party vendors.
520 $a Semiconductor colloidal quantum wells (CQWs) make an exciting quasi-2D class of nanocrystals thanks to their unique properties emerging from their atomically-flat verticallythin geometry including highly anisotropic optical transition dipole moment (TDM), giant oscillator strength, and extraordinarily high absorption cross-section. This regular shape of the CQWs enables them to assemble on the surface of a liquid with a high degree of packing, which creates an almost fully uniform monolayer film with the desired orientation. Nearly all of the emission in a single CQW, again because of its geometry, comes from in-plane (IP) transition dipole moments (TDMs). Thus, an assembled film of such CQWs with an all-facedown orientation may show a highly anisotropic and directional emission. Using such a film in an emissive layer (EML) of an electroluminescent device, in this thesis work our intention is therefore to substantially boost photon outcoupling efficiency in a light-emitting device of oriented monolayer of CQWs. Thus far, research efforts have been conducted to investigate the properties of the deposited film of CQWs with self-assembly. However, in all of the previous studies, the property of CQW monolayer has been investigated only in a passive film; therefore, investigation of the self-assembled film in an active device is lacking. In this thesis, we developed and demonstrated an all-solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) using a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that enables a high level of IP TDMs of 92%. This film significantly enhances the outcoupling efficiency of LEDs from 22% (of standard randomlyoriented emitters) to 34% (of face-down oriented emitters). As a result of the outcoupling efficiency increased by 1.55 times, along with the enhanced charge injection and reduced reabsorption in the case of using a single SAM of CQWs, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with those of the hybrid organic-inorganic evaporationbased CQW-LEDs and all other best solution-processed LEDs. This EQE value is 65% higher than that in the devices fabricated by spin-coating with the same procedure and structure. Also, the SAM-CQW-LED architecture enables a high maximum brightness of 19,800 cd/m2 with a long operational lifetime of 247 h at 100 cd/m2 , as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV and a high J90 of 99.58 mA/cm2 . These findings indicate the effectiveness of oriented self-assembly of CQWs as electrically-driven emissive layers in improving outcoupling and external quantum efficiencies in the CQW-LEDs.
520 $a Yariiletken koloidal kuantum kuyulari, yuksek yonbagimli optik gecis dipol momenti, oldukca buyuk salinim gucu ve olaganustu yuksek sogurma kesit yuzeyi dahil olmak uzere atomik olarak duz ve dikey olarak ince geometrilerinden ortaya cikan benzersiz ozellikleri sayesinde dikkat ceken iki boyutlu nanokristaller sinifini olusturur. Koloidal kuantum kuyularinin duzenli sekli, neredeyse tamami ayni sekilli ve tek katmanli bir film olusturarak yuksek derecede istiflenme ozellikleri ile sivi yuzeyinde bir araya gelmelerini saglar. Bir koloidal kuantum kuyusunda olusan isima buyuk bulumu geometrisinden kaynaklanan duzlem ici gecis dipol momentleri sayesinde olusur. Bu nedenle koloidal kuantum kuyularinin tamami asagi donuk bir yonelimle dizilerek olusturdugu film, yuksek oranda yonbagimli ve yonlu bir isima gosterir. Bu tez calismasinda, amac, yonlendirilmis koloidal kuantum kuyularini bahsedilen film elektroisiyan katmaninda kullanarak isik yayan aygitlarin foton cikarma verimliligini arttirmaktir. Bu zamana kadar bu konuda ozdizilim uzerine yapilan arastirmalar koloidal kuantum kuyularindan olusan ozdizili film icinde ozelliklerini arastirmak uzerinedir. Onceki calismalarin tumunde koloidal kuantum kuyularinin tekli katmanlari sadece pasif bir filmde calisilmistir, fakat ozdizili filmin aktif bir cihaz icinde arastirilmasi eksiktir. Bu tezde tumu asagi yonlenmis olan ozdizili ve tek katmanli film, isik yayan diyotlar icinde kullanilmis, %92’ye varan oranda yuzey ici gecis dipol momenti elde edilmistir. Bu ozdizili film, LED'lerin foton cikarma verimliligini onemli olcude arttirmis, %22'den (standart rastgele dizilmis isiyicilar icin) %34'e kadar (yuzu asagi yonlendirilmis isiyicilar icin) yukseltilmistir. Arttirilmis yuk enjeksiyonu ve azaltilmis yeniden sogurma ozelligi ile tek katmanli koloidal kuantum kuyularindan olusan ozdizili filmin foton cikarma verimi 1.55 kat yukseltilmistir. Tumu cozeltide gerceklestirilen ve dis kuantum verimi rekor seviyede %18.1’e ulasan koloidal kuantum kuyularinin kullanildigi isik yayan diyotlar, hibrit organik-inorganik buharlasma temelli koloidal kuantum kuyulari ve diger yuksek performansa sahip cozelti-temelli isik yayan diyotlar ile benzer bir verimliligine cikmistir. Dis kuantum verimliligi %65 ile, ayni prosedur ve benzer bir yapi ile dondurulerek kaplanmis aygitlardan daha yuksektir. Ayrica, tek katmanli ozdizili koloidal kuantum kuyularinin kullanildigi aygit, 100 cd/m2 ' isildama seviyesinde 247 saatlik uzun calisma omruyle 19.800 cd/m2 maksimum parlakliga ulasmistir. 1.7 eV’luk dusuk calisma voltaji ve 99.58 mA/cm2 ’lik yuksek akim yogunluguna sahip olan aygit, kararli ve asiri doygun kirmizi isima gostermektedir. Bu ciktilar, yonlenmis ve ozdizili koloidal kuantum kuyularinin elektrikle calisan isiyici katmanlarda kullanilmasi, foton cikarimi ve dis kuantum verimliliklerini iyilestirmedeki etkinligini gostermektedir.
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