A study of the diimmonium dyes employing bis(fluorosulfonyl)imide anions for NIR absorbing film of CMOS image sensor

Development of benzo[cd]indolenyl cyanine dyes for NIR-absorbing films and elucidation of molecular structure–spectroscopic relationship

“…The difference in the spectral characteristics between these films can be explained by the “ion-pairing effect” between the cyanine chromophore and the counter anion. 24,47–49…”

Enhancement of NIR‐Absorbing Ability of Bis(diarylmethylium)‐Type Dicationic Dyes Based on an Ortho‐Substitution Strategy.

“…Organic dyes such as cyanines, [1][2][3] squaliums, [4,5] and diimmoniums, [6,7] and organometallic complexes such as nickel dithiolenes [8] and phthalocyanines [9] show a narrow energy gap which has been attributed to a long-range π-conjugation based on the effective delocalization of N/O-based cations and charge-transfer (CT) interactions based on metal ions, respectively. Thus, they are known to exhibit near-infrared (NIR) absorption in the range of 700-2000 nm.…”

Click reactions to prepare symmetrical and asymmetrical and broad-band near-infrared absorbing dyes

“…22 These chromophores exhibit intense, low-energy, intramolecular charge transfer and high third-order optical nonlinearities. [23][24][25][26] Using this rapid and efficient synthesis method and click chemical reagents, many materials with good third-order nonlinear optical properties have been prepared, such as porphyrin, fullerene and thiophene derivatives. Nevertheless, materials prepared via the [2+2] click reaction can only absorb a portion of the visible band, and such materials that absorb over a wide band have never been reported.…”