Effect of substituent structure in fluorene based compounds: Experimental and theoretical study

•Six new fluorene–based low molar weight derivatives were synthesized.•They showed similar LUMO (ca. 3.1 eV) and HOMO energy levels in the range of – 6.01 to – 5.35 eV.•Their spectroscopic properties in solution and solid state were investigated.•The molecules with phenyl, TPA and naphthalene units as thin film emitted light (λem = 462 – 589 nm).•Compound with TPA and phenyl units in organic–inorganic PV cell increased PCE by more than 30%.