@article{Permatasari2023, 
author = {Fitri Aulia Permatasari and Reza Umami and Citra Deliana Dewi Sundari and Tirta Rona Mayangsari and Atthar Luqman Ivansyah and Fahdzi Muttaqien and Takashi Ogi and Ferry Iskandar},
title = {New insight into pyrrolic-N site effect towards the first NIR window absorption of pyrrolic-N-rich carbon dots},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {4},
pages = {6001-6009},
keywords = {charge transfer, carbon dots, absorption, first near infrared (NIR) window, frontier orbital hybridization, mid-site pyrrolic-N},
url = {https://www.sciopen.com/article/10.1007/s12274-022-5131-7},
doi = {10.1007/s12274-022-5131-7},
abstract = {Controlled C–N configurations, i.e., pyrrolic-N, pyridinic-N, and graphitic-N, are promising strategies to tailor the carbon dots’ (CDs) optical properties into the first near infrared (NIR) window (650–900 nm), a responsive range for biomedical application. However, a deep understanding of the role of the C–N configuration in the CDs’ properties is still challenging and thought-provoking owing to their complex structure. Here, an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’ absorption was comprehensively elucidated based on the integrated experimental and computational studies. The as-synthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion. Pyrrolic-N concentrations from 1.4% to 11.3% and positions (edge and mid-site) were systematically investigated. A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%. Edge-site pyrrolic-N induces a frontier orbital hybridization, reducing bandgap energy, while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer. Also, pyrrolic-N-rich CDs inherit a bowl-like topological feature, elevating the CDs’ layer thickness as much as 0.71 nm. This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.}
}