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Title: Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC); Argonne-Northwestern Solar Energy Research Center (ANSER)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1210327
DOE Contract Number:
SC0001059
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 136; Related Information: ANSER partners with Northwestern University (lead); Argonne National Laboratory; University of Chicago; University of Illinois, Urbana-Champaign; Yale University
Country of Publication:
United States
Language:
English
Subject:
catalysis (homogeneous), catalysis (heterogeneous), solar (photovoltaic), solar (fuels), photosynthesis (natural and artificial), bio-inspired, hydrogen and fuel cells, electrodes - solar, defects, charge transport, spin dynamics, membrane, materials and chemistry by design, optics, synthesis (novel materials), synthesis (self-assembly)

Citation Formats

Negre, Christian F. A., Young, Karin J., Oviedo, Ma Belén, Allen, Laura J., Sánchez, Cristián G., Jarzembska, Katarzyna N., Benedict, Jason B., Crabtree, Robert H., Coppens, Philip, Brudvig, Gary W., and Batista, Victor S. Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates. United States: N. p., 2014. Web. doi:10.1021/ja509270f.
Negre, Christian F. A., Young, Karin J., Oviedo, Ma Belén, Allen, Laura J., Sánchez, Cristián G., Jarzembska, Katarzyna N., Benedict, Jason B., Crabtree, Robert H., Coppens, Philip, Brudvig, Gary W., & Batista, Victor S. Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates. United States. doi:10.1021/ja509270f.
Negre, Christian F. A., Young, Karin J., Oviedo, Ma Belén, Allen, Laura J., Sánchez, Cristián G., Jarzembska, Katarzyna N., Benedict, Jason B., Crabtree, Robert H., Coppens, Philip, Brudvig, Gary W., and Batista, Victor S. Wed . "Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates". United States. doi:10.1021/ja509270f.
@article{osti_1210327,
title = {Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates},
author = {Negre, Christian F. A. and Young, Karin J. and Oviedo, Ma Belén and Allen, Laura J. and Sánchez, Cristián G. and Jarzembska, Katarzyna N. and Benedict, Jason B. and Crabtree, Robert H. and Coppens, Philip and Brudvig, Gary W. and Batista, Victor S.},
abstractNote = {},
doi = {10.1021/ja509270f},
journal = {Journal of the American Chemical Society},
number = ,
volume = 136,
place = {United States},
year = {Wed Nov 19 00:00:00 EST 2014},
month = {Wed Nov 19 00:00:00 EST 2014}
}
  • In this paper, the authors examine the effects of hole carrier injection and mobility on both the electroluminescence (EL) quantum efficiency and the operating voltage of bilayer organic light-emitting diodes (OLED`s). They find that hole-injection is limited by the nature of the hole injecting interface and significantly affects the operating voltage, but not the quantum efficiency of the OLED. Hole mobility is found not to affect the device quantum efficiency. They demonstrate the characteristics of an ideal ohmic contact by measuring space-charge-limited currents in a trap-free hole transporting polymer layer.
  • High efficiency/high luminance small-molecule organic light-emitting diodes (OLEDs) are fabricated by combining thin, covalently bound triarylamine hole injection/adhesion interlayers with hole- and exciton-blocking/electron transport interlayers in tris(8-hydroxyquinolato)aluminum(III) (Alq) and tetrakis(2-methyl-8-hydroxyquinolinato)borate (BQ{sub 4}{sup -})-based OLEDs. Green-emitting OLEDs with maximum luminance {approx}85 000 cd/m{sup 2}, power and forward external quantum efficiencies as high as 15.2 lm/W and 4.4{+-}0.5%, respectively, and turn-on voltages {approx}4.5 V are achieved in devices of the structure, ITO/N,N(prime)-diphenyl-N,N(prime)-bis(p-trichlorosilylpropylphenyl)(1,1(prime)-biphenyl)-4,4(prime)-diamine (TPD-Si2)/1,4-bis(1-naphthylphenylamino)biphenyl (NPB)/Alq doped with N,N(prime)-di(3-heptyl)quinacridone (DIQA)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/Li/AgMg. Also, bright and efficient blue-emitting OLEDs with turn-on voltages {approx}5.0 V, maximum luminance {approx}30 000 cd/m2, and {approx}5.0 lm/W and 1.6{+-}0.2% power andmore » external forward quantum efficiencies, respectively, are achieved in devices of the structure, ITO/TPD-Si2/NPB/BQ{sub 4}{sup -}/BCP/Li/Al. TPD-Si2 interlayers are fabricated by spin casting N,N(prime)-diphenyl-N,N(prime)-bis(p-trichlorosilylpropylphenyl)(1,1(prime)-biphenyl)-4,4(prime)-diamine onto the ITO surface, while BCP interlayers are introduced by thermal evaporation. The excellent OLED performance is attributed to the differing functions of the above two interlayers: (1) The TPD-Si2 layer has a direct impact on hole injection by reducing the injection barrier and improving interfacial cohesion, and an indirect but strong effect on electron injection by altering internal electric fields. (2) The BCP layer, doped with lithium, directly reduces the electron injection barrier. Incorporation of both interlayers in OLED structures affords synergistically enhanced hole/electron injection and recombination efficiency. The results demonstrate a strategy to enhance OLED performance and an alternative strategy to increase electron density in electron-limited devices.« less