Batch-to-batch variation of polymeric photovoltaic materials: Its origin and impacts on charge carrier transport and device performances

Download
  1. Get@NRC: Batch-to-batch variation of polymeric photovoltaic materials: Its origin and impacts on charge carrier transport and device performances (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1002/aenm.201400768
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleAdvanced Energy Materials
ISSN1614-6832
Volume4
Issue16
SubjectCarrier mobility; Carrier transport; Charge carriers; Charge transfer; Chromatography; Gel permeation chromatography; Molecular weight; Molecular weight distribution; Polycyclic aromatic hydrocarbons; Transport properties; Batch-to-batch variations; Gaussian disorder models; Gel permeation chromatography (GPC); Hopping distances; Photovoltaic devices; Photovoltaic performance; Power conversion efficiencies; Semiconducting materials; Polymers
AbstractA detailed investigation of the impact of molecular weight distribution of a photoactive polymer, poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT), on photovoltaic device performance and carrier transport properties is reported. It is found that different batches of as-received polymers have substantial differences in their molecular weight distribution. As revealed by gel permeation chromatography (GPC), two peaks can generally be observed. One of the peaks corresponds to a high molecular weight component and the other peak corresponds to a low molecular weight component. Photovoltaic devices fabricated with a higher proportion of low molecular weight component have power conversion efficiencies (PCEs) reduced from 5.7% to 2.5%. The corresponding charge carrier mobility at the short-circuit region is also significantly reduced from 2.7 × 10-5 to 1.6 × 10-8 cm2 V-1 s-1. The carrier transport properties of the polymers at various temperatures are further analyzed by the Gaussian disorder model (GDM). All polymers have similar energetic disorders. However, they appear to have significant differences in carrier hopping distances. This result provides insight into the origin of the molecular weight effect on carrier transport in polymeric semiconducting materials. Batch-to-batch variation of the photovoltaic performance of devices based on commercial samples of the polymer poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5- (4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) is reported, with efficiency ranging from 5.7% to 2.5%. As revealed by gel permeation chromatography, bimodal distributions are observed in the molecular weight. Charge transport data suggest that low molecular weight components increase the average hopping distance, resulting in lower mobility and poorer photovoltaic performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Publication date
PublisherWiley
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); Security and Disruptive Technologies
Peer reviewedYes
NPARC number21275470
Export citationExport as RIS
Report a correctionReport a correction
Record identifier9e323c7a-959c-4041-870d-cbd5a93d4b7b
Record created2015-07-14
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)