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
Over the past decade, the photovoltaic (PV) performance of perovskite solar cells (PSCs) has been considerably improved with the development of perovskite photoabsorbers. Among these, formamidinium-lead-iodide (FAPbI) is a promising photoabsorber owing to its narrow bandgap and is mainly used in n-i-p-structured PSCs. The property modulation of FAPbI photoabsorbers while retaining their narrow bandgap is imperative for further development of PSCs. Molecular tetrafluoroborate anion (BF)-based materials can be used as additives in perovskite layers to prevent bandgap widening, while facilitating perovskite crystal growth; thus, they are suitable for FAPbI photoabsorbers in principle. However, BF-based additives for narrow-bandgap FAPbI photoabsorbers have not been developed. This is presumably because of the higher temperatures required for FAPbI formation than that for other wide-bandgap perovskites, which likely changes the effects of BF-based additives from those for wide-bandgap perovskites. In this study, we verified the applicability of methylammonium tetrafluoroborate (MABF) as an additive in narrow-bandgap FAPbI photoabsorbers for improving their PV performance primarily via the spontaneous modulation of the heterointerfaces between FAPbI and carrier-transport materials, rather than the bulk quality improvement of FAPbI perovskite. At the interface of the hole-transport material and FAPbI, MABF addition effectively eliminates the surface defects in all FAPbI components, even in the absence of BF over the heated FAPbI surface, suggesting a defect-suppression mechanism that differs from that observed in conventional ones. Moreover, at the interface of FAPbI and the TiO electron-transport material, the BF-derived species, which likely includes decomposed BF owing to the high-temperature heating, spontaneously segregates upon deposition, thereby modulating the heterointerface. Furthermore, in addition to the carrier mobility ratio in FAPbI (e:h ≈ 7:3), a time-resolved microwave conductivity measurement revealed that MABF addition eliminates carrier traps at the heterointerfaces. Our findings provide insights into promising FAPbI-based PSCs, offering a valuable tool for their further development.
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Source |
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http://dx.doi.org/10.1021/acsami.4c11784 | DOI Listing |
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