Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
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File: /var/www/html/application/helpers/my_audit_helper.php
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Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
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Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3098
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
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Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
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Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
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Function: require_once
Severity: Warning
Message: Attempt to read property "Count" on bool
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File: /var/www/html/application/helpers/my_audit_helper.php
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Function: _error_handler
File: /var/www/html/application/controllers/Detail.php
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Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
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Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
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Function: require_once
Two-dimensional (2D) chiral hybrid perovskites A2PbI4 (A: chiral organic ion) enable chirality controlled optoelectronic and spin-based properties. A+ organic sublattice induces chirality into the semiconducting [PbI4]2- inorganic sublattice through non-covalent interactions at organic-inorganic interface. Often, the A+ cations in the lattice have different orientations, leading to asymmetry in the non-covalent interactions. In a novel approach, we use different conformers of A+ cations to create asymmetry in the non-covalent interactions, thereby, achieving chiral perovskites with rare helical enantiomorphic structures. We prepared (R-IdPA)2PbI4 and (S-IdPA)2PbI4 (IdPA: 1-iodopropan-2-ammonium) which crystallize in the helical enantiomorphic space groups P43212 and P41212, respectively. The gauche- and anti-conformers of IdPA+ are arranged alternatively in the hybrid structure. Importantly, the anti-conformer of IdPA+ ion have significantly stronger electrostatic, N-H···I hydrogen bonding, and I···I halogen bonding interactions with the [PbI4]2- sublattice, compared to the gauche-conformer. This periodic asymmetry in non-covalent interactions caused by the alternative arrangement of gauche- and anti-conformers induces chirality in the inorganic sublattice with four-fold screw axes (4₃ and 4₁). The enantiomers (R-/S-IAP)2PbI4 show mirror-image like circular dichroism from excitonic absorption of the inorganic sublattice. This conformer-based design of chiral hybrid perovskites in helical space groups broadens material choices for advanced optoelectronic applications.
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Source |
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http://dx.doi.org/10.1002/anie.202422550 | DOI Listing |
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