東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Silicon quantum dots mesomaterial fo...

Li, Huashan.

FindBook

Google Book

Amazon

博客來

Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites./
作者:	Li, Huashan.
面頁冊數:	183 p.
附註:	Source: Dissertation Abstracts International, Volume: 75-07(E), Section: B.
Contained By:	Dissertation Abstracts International75-07B(E).
標題:	Physics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3615848
ISBN:	9781303823473

Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites.
Li, Huashan.

Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites. - 183 p.

Source: Dissertation Abstracts International, Volume: 75-07(E), Section: B.

Thesis (Ph.D.)--Colorado School of Mines, 2014.

This item is not available from ProQuest Dissertations & Theses.

Designing innovative architectures for silicon quantum dot (SiQD) mesomaterials is the key to achieving their promise for implementation in the third generation solar cells. To this end, we have developed a computational methodology that predicts the optical properties and charge dynamics for these hybrid nanoscale structures. Specifically, a way of computationally estimating the effective energy level alignment at heterojunctions was derived to characterize junction types and interfacial charge separation character. Next, a full quantum treatment was developed to calculate transition rates within the setting of incoherent, phonon-assisted carrier hopping. This model was applied to consider transport within the organic/inorganic SiQD/P3HT system, and it was found to accurately capture the charge transfer and photoluminescence rates. In particular, with dangling bonds accounted for, the method recovers the charge recombination and electron hopping rates observed experimentally. The analysis pinpointed the source of the poor photo-conversion efficiency as being due to dangling bond defects. With the appropriate computational tools in hand, we then considered new nanostructure architectures intended to overcome the drawbacks of those already proposed. Three general strategies for designing future photovoltaic devices were developed. The first is based on the concept of short bridge networks, a new type-II quantum dot mesomaterial in which the dots are connected by covalently bonded, short-bridge molecules. There we found that both polaron dissociation and subsequent carrier hopping are significantly enhanced by a double superexchange mechanism in which the electronic coupling of both carrier types is aided by the presence of mediating, non-resonant material. The second strategy that we developed is associated with the harvesting of low energy photons via direct generation of spatially separated excitons. To achieve this goal, we found that two criteria need to be satisfied between quantum dots and their functionalizing termination group: they have to have a type-II energy level alignment; and they need to be joined via a conjugating vinyl bond. In principle, the absorption edge can be made arbitrarily small and is no longer dependent on quantum dot size. We were able to create a proof-of-concept assembly demonstrating this concept. The third design strategy developed in this dissertation research was to optimize dot size to achieve high stability in ambient environments. Specifically, we predict that appropriately terminated silicon quantum dots with diameters in the range of 1.2-2 nm will be extremely resistant to oxidation. This is because of the absence of both surface defects and geometry-related vulnerabilities allowing even very short passivating ligands to generate a large barrier to oxidation processes.

ISBN: 9781303823473Subjects--Topical Terms:

516296
Physics.

Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites.
LDR:03900nmm a2200301 4500 001 2066167
005 20151217135745.5
008 170521s2014 ||||||||||||||||| ||eng d
020 $a 9781303823473
035 $a (MiAaPQ)AAI3615848
035 $a AAI3615848
040 $a MiAaPQ $c MiAaPQ
100 1 $a Li, Huashan. $3 3180936
245 1 0 $a Silicon quantum dots mesomaterial for improved optical properties and charge dynamics in third generation photovoltaic composites.
300 $a 183 p.
500 $a Source: Dissertation Abstracts International, Volume: 75-07(E), Section: B.
500 $a Advisers: Mark T. Lusk; Zhigang Wu.
502 $a Thesis (Ph.D.)--Colorado School of Mines, 2014.
506 $a This item is not available from ProQuest Dissertations & Theses.
520 $a Designing innovative architectures for silicon quantum dot (SiQD) mesomaterials is the key to achieving their promise for implementation in the third generation solar cells. To this end, we have developed a computational methodology that predicts the optical properties and charge dynamics for these hybrid nanoscale structures. Specifically, a way of computationally estimating the effective energy level alignment at heterojunctions was derived to characterize junction types and interfacial charge separation character. Next, a full quantum treatment was developed to calculate transition rates within the setting of incoherent, phonon-assisted carrier hopping. This model was applied to consider transport within the organic/inorganic SiQD/P3HT system, and it was found to accurately capture the charge transfer and photoluminescence rates. In particular, with dangling bonds accounted for, the method recovers the charge recombination and electron hopping rates observed experimentally. The analysis pinpointed the source of the poor photo-conversion efficiency as being due to dangling bond defects. With the appropriate computational tools in hand, we then considered new nanostructure architectures intended to overcome the drawbacks of those already proposed. Three general strategies for designing future photovoltaic devices were developed. The first is based on the concept of short bridge networks, a new type-II quantum dot mesomaterial in which the dots are connected by covalently bonded, short-bridge molecules. There we found that both polaron dissociation and subsequent carrier hopping are significantly enhanced by a double superexchange mechanism in which the electronic coupling of both carrier types is aided by the presence of mediating, non-resonant material. The second strategy that we developed is associated with the harvesting of low energy photons via direct generation of spatially separated excitons. To achieve this goal, we found that two criteria need to be satisfied between quantum dots and their functionalizing termination group: they have to have a type-II energy level alignment; and they need to be joined via a conjugating vinyl bond. In principle, the absorption edge can be made arbitrarily small and is no longer dependent on quantum dot size. We were able to create a proof-of-concept assembly demonstrating this concept. The third design strategy developed in this dissertation research was to optimize dot size to achieve high stability in ambient environments. Specifically, we predict that appropriately terminated silicon quantum dots with diameters in the range of 1.2-2 nm will be extremely resistant to oxidation. This is because of the absence of both surface defects and geometry-related vulnerabilities allowing even very short passivating ligands to generate a large barrier to oxidation processes.
590 $a School code: 0052.
650 4 $a Physics. $3 516296
650 4 $a Materials science. $3 543314
650 4 $a Optics. $3 517925
690 $a 0605
690 $a 0794
690 $a 0752
710 2 $a Colorado School of Mines. $b Physics. $3 2093652
773 0 $t Dissertation Abstracts International $g 75-07B(E).
790 $a 0052
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3615848