Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
For all-polymer solar cells which are composed of polymer donors and polymer acceptors, the effect of alkyl side chains on photovoltaic performance is a matter of some debate, and this effect remains difficult to forecast. In this concise contribution, we demonstrate that three alkyls namely branched alkyl 2-butyloctyl (2BO), long linear alkyl n-dodecyl (C12), and double-short linear alkyl n-hexyls (DC6) incorporated into the side chains of large bandgap polymer donor PBDT-TTz can induce considerable, of significance, and different electronic, optical, and morphological parameters. Systematic studies shed light on the critical role of the double-short linear alkyl n-hexyls (DC6) in (i) producing large ionization potential value, (ii) increasing propensity of the polymer to order along the π-stacking direction, (iii) generating polymer crystallites with more preferential "face-on" orientation, consequently, (iv) improvement of carriers transportation, (v) suppression of charge recombination, (vi) reduction of energy loss in all-polymer devices. In parallel, we unearth that the PBDT-TTz with double-short linear alkyl n-hexyls (DC6) represents the highest efficiency of 8.3 %, whereas, the other two PBDT-TTz analogues (2BO, C12) yield efficiencies of less than 3 % in optimized all-polymer solar cells. Though branched or long linear alkyl side chains (2BO, C12) have been applied to provide the solution processability of conjugated polymers, motifs bearing multiple short linear alkyl substituents (DC6) are proved critical to the development of high performing polymers.
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Source |
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http://dx.doi.org/10.1002/cphc.202000176 | DOI Listing |
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