Theoretical study on the bridge comparison of TiO2 nanoparticle sensitizers based on phenoxazine in dye-sensitized solar cells

Electronic and optical properties’ tuning of phenoxazine-based D-A2-π-A1 organic dyes for dye-sensitized solar cells. DFT/TDDFT investigations

“…Many metal-free organic dyes including phenothiazine [ 14 ], carbazoles, coumarin, triarylamines, triphenylamine [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], or phenoxazine [ 24 , 25 , 26 , 27 ] have been designed and synthesized and found to possess promising properties that can enhance photovoltaic performances better than most prominent metal complex dyes. In recent times, phenoxazine has shown preference as an electron-donating moiety.…”

“…Higher oxidation potential and lower aromatic energy of furan as π-spacer has been reported to aid stability of the dye and improve power conversion efficiency [ 30 ] amongst many other π-spacers such as pyrrole, thiazole, benzene or thiophene used in the study of organic dyes [ 14 , 25 , 31 ]. According to Buene and co-workers [ 32 ], furan π-spacer performed better than popular π -spacers such as thiophene and phenyl, therefore the use of furan as π-spacer is encouraged to facilitate intramolecular charge transfer from donor to acceptor [ 14 ].…”

“…According to Buene and co-workers [ 32 ], furan π-spacer performed better than popular π -spacers such as thiophene and phenyl, therefore the use of furan as π-spacer is encouraged to facilitate intramolecular charge transfer from donor to acceptor [ 14 ]. The acceptor group can perform the function of an electron trap and also an anchor group [ 14 , 15 , 25 , 27 ]. Cyanoacrylic acid is regarded as an excellent electron acceptor owing to its excellent electron withdrawing ability [ 33 ] compared to various reported acceptor groups such as benzothiadiazole or 2-cyano-2-pyran-4-ylidene-acetic acid [ 14 , 30 ].…”

“…This paper adopts a D-A 2 -π-A 1 design, Figure 1 a using the phenoxazine-based ring as electron-donating unit, while benzothiadiazole (A 2 ) was introduced between electron donor and π-spacer as 'electron trap' tool to fine-tune the HOMO-LUMO gap, broaden the light-harvesting range and promote the electron transfer from donor to anchor [ 14 ]. Furan was employed as a π-conjugated bridge to enhance intramolecular charge transfer [ 25 , 32 ]. Cyanoacrylic acid is pivotal in anchoring the dye into the semiconductor and improving cell efficiency [ 15 ].…”

Small Heterocyclic D‐π‐D‐π‐A Push‐Pull Molecules with Complex Electron Donors

“…On the other hand, recent theoretical and experimental studies showed that proper involvement of thiophene, pyrrole, and furan rings in the chromophore backbone may bring organic materials with advanced properties. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Despite their popularity as auxiliary donors, [32] a combination of five-membered heterocyclic and mesomeric donors has been practically realized only on thiophene. [33][34][35] Pyrrole or furan π-linkers with appended alkoxy or amino mesomeric donors are scarce.…”