SwePub
Sök i LIBRIS databas

  Utökad sökning

WFRF:(El Zohry Ahmed)
 

Sökning: WFRF:(El Zohry Ahmed) > (2012-2014) > Concentration and S...

LIBRIS Formathandbok  (Information om MARC21)
FältnamnIndikatorerMetadata
00003041naa a2200277 4500
001oai:DiVA.org:uu-200071
003SwePub
008130520s2013 | |||||||||||000 ||eng|
024a https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2000712 URI
024a https://doi.org/10.1021/jp400782g2 DOI
040 a (SwePub)uu
041 a engb eng
042 9 SwePub
072 7a ref2 swepub-contenttype
072 7a art2 swepub-publicationtype
100a El-Zohry, Ahmed M.u Uppsala universitet,Fysikalisk kemi4 aut0 (Swepub:uu)ahmel473
2451 0a Concentration and Solvent Effects on the Excited State Dynamics of the Solar Cell Dye D149 :b The Special Role of Protons
264 c 2013-03-21
264 1b American Chemical Society (ACS),c 2013
338 a print2 rdacarrier
520 a D149 is one of the best-performing metal-free, organic dyes for dye-sensitized solar cells. Excited state lifetimes strongly depend on the solvent used and have previously been reported to be between 100 and 700 ps, without any mechanistic explanation being given. We have earlier shown that photo-isomerization is one of several deactivation processes. Here, we report that lifetimes in certain solvents depend on concentration, even in very dilute (nanomolar) solutions. A detailed investigation of the concentration dependence enables us to assign a second, faster deactivation channel besides isomerization that reduces lifetimes further: a ground-state, hydrogen-bonded 1:1 complex of D149 with acids or interaction with protic solvents leads to excited state quenching, most probably through excited state proton transfer. This includes self-quenching caused by D149's own carboxylic group through intermolecular interaction, accounting for the concentration-dependent lifetimes. We are now able to dissect the complex excited state behavior into its components, allowing us to attribute rate constants to the isomerization and the excited-state proton transfer process. We are also able to explain the excited state of D149 in a wide range of environmental conditions, in the presence of acids/bases, at different concentrations as well as with varying temperatures. Furthermore, we determine the barrier for isomerization, a thermally activated process. The consequences of these effects on solar cells are discussed. Also we show that ultrafast techniques like femtosecond pump probe and upconversion inherently do not provide the required responsiveness for work with the concentration ranges required here, whereas single photon counting with its ultimate sensitivity is able to resolve the underlying processes.
700a Zietz, Burkhardu Uppsala universitet,Fysikalisk kemi4 aut0 (Swepub:uu)burzi244
710a Uppsala universitetb Fysikalisk kemi4 org
773t The Journal of Physical Chemistry Cd : American Chemical Society (ACS)g 117:13, s. 6544-6553q 117:13<6544-6553x 1932-7447x 1932-7455
8564 8u https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-200071
8564 8u https://doi.org/10.1021/jp400782g

Hitta via bibliotek

Till lärosätets databas

Hitta mer i SwePub

Av författaren/redakt...
El-Zohry, Ahmed ...
Zietz, Burkhard
Artiklar i publikationen
The Journal of P ...
Av lärosätet
Uppsala universitet

Sök utanför SwePub

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy