Designing dibenzosilole and methyl carbazole based donor materials with favourable photovoltaic parameters for bulk heterojunction organic solar cells

• Five new Acceptor-Donor-Acceptor (A-D-A) type small donor molecules (M1-M5) namely; Dimethyl cyanoacetate terthiophene di(methylthiophene) dibenzosilole (DMCAO3TBS) (M1), Dimelononitrile terthiophene di(methylthiophene) dibenzosilole (DMCNTBS) (M2), Dimethyl rhodanine terthiophene di(methylthiophene) dibenzosilole (DMRTBS) (M3), Dimelanonitrile terthiophene di(methylthiophene) methyl carbazole (DMCNTCz) (M4) and Dimethyl rhodanine terthiophene di(methylthiophene) methyl carbazole (DMRTCz) (M5) were designed and theoretically explored their electronic, photophysical and geometrical properties via DFT best functional MPW1PW91/6-311G (d,p) with respect to reference molecules Dioctyl cyanoacetate terthiophene di(octylthiophene) dioctylfluorene (DCAO3TF) (Ra) and Dioctyl cyanoacetate terthiophene di(octylthiophene) octylcarbazole (DCAO3TCz) (Rb). Among the designed donor molecules (M1-M5), M2 and M4 represented lowest band gap value (2.480 eV and 2.47 eV) with distinctive broad absorption peak at 598 nm and 601 nm in chloroform. Theoretically estimated reorganization energies of these molecules recommended excellent property of charge mobility. The designed donor molecules (M1-M5), demonstrated lower λe value with reference to their λh, showing that these molecules could be ideal candidates for the transfer of electron while M2 and M4 were found to be best molecules having lowest λe (0.006 eV and 0.005 eV respectively). Additionally the Voc of M2 and M4 are 2.01 eV and 1.85 eV respectively with respect to PCBM.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

Absorption

Dibenzosilole

Computational chemistry

Methyl carbazole

Reorganization energy

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