Effective D-A-D type chromophore of fumaronitrile-core and terminal alkylated bithiophene for solution-processed small molecule organic solar cells

Abstract

A new and novel organic π-conjugated chromophore (named as RCNR) based on fumaronitrile-core acceptor and terminal alkylated bithiophene was designed, synthesized and utilized as an electron-donor material for the solution-processed fabrication of bulk-heterojunction (BHJ) small molecule organic solar cells (SMOSCs). The synthesized organic chromophore exhibited a broad absorption peak near green region and strong emission peak due to the presence of strong electron-withdrawing nature of two nitrile (–CN) groups of fumaronitrile acceptor. The highest occupied molecular orbital (HOMO) energy level of –5.82 eV and the lowest unoccupied molecular orbital (LUMO) energy level of –3.54 eV were estimated for RCNR due to the strong electron-accepting tendency of –CN groups. The fabricated SMOSC devices with RCNR:PC60BM (1:3, w/w) active layer exhibited the reasonable power conversion efficiency (PCE) of ~2.69% with high short-circuit current density (JSC) of ~9.68 mA/cm2 and open circuit voltage (VOC) of ~0.79 V.

Theoretical-Experimental Photophysical Investigations of the Solvent Effect on the Properties of Green- and Blue-Light-Emitting Quinoline Derivatives

“…Compounds with a large change in their permanent dipole moment upon excitation exhibit a strong solvatochromism. In compounds 3 and 4, this was observed in different intensity [30].…”

Intramolecular Charge Transfer and Solvation of Photoactive Molecules with Conjugated Push–Pull Structures

“…[1][2][3][4][5][6] The principal properties of organic functional materials are strongly dependent on the ICT between donor and acceptor groups, which affords good tunability of their spectral properties through appropriate modification of the chemical structures of the donora nd acceptor substituents and/or the p-conjugated linkers. [7][8][9][10][11][12] For example, al arge ICT might help to reduce the bandgapf or red emission. [13][14][15][16] The fluorescenceq uantum yield, fluorescence lifetime, nonlinearo ptical effects, thermals tability and solubility could be changed by choosing different strengthd onors or acceptors and/or extending the conjugation length between the donor and acceptor.…”

“…[13][14][15][16] The fluorescenceq uantum yield, fluorescence lifetime, nonlinearo ptical effects, thermals tability and solubility could be changed by choosing different strengthd onors or acceptors and/or extending the conjugation length between the donor and acceptor. [7,15,[17][18][19] In addition to thep ush-pull molecular properties, the surrounding environmentw ill also have as ignificant influence on their spectralp roperties. [20,21] Furthermore, for photovoltaic devices that achieve high conversion efficiency,t he materials used are generally required to generate ah igh degree of charge transfer,a nd furthermore, form the long-lived charge-separated state.…”

Ultrafast Investigation of Intramolecular Charge Transfer and Solvation Dynamics of Tetrahydro[5]-helicene-Based Imide Derivatives

“…Organic molecular materials with electronic push-pull properties have attracted considerable attention because their photophysical properties based on intramolecular charge transfer (ICT) could be widely tuned through appropriate modification of the chemical structures of donor, acceptor substitutes and/or the π-conjugated linkers for practical applications 1 2 3 4 5 6 . The photophysical properties, such as fluorescence quantum yield, fluorescence lifetime, especially the band gap of these organic molecules are strongly dependent on the ICT characteristic from different push-pull abilities between donor and acceptor 7 8 9 10 . Obviously, the chemical structures and surrounding environments could be the most critical factors for their practical behaviors 11 12 13 14 15 .…”