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This study focuses on optoelectronic features of a series of D-A-D molecules composed of thiophene, ethylenedioxythiophene, or 3,4-dimethoxythiophene acceptor groups substituted in several positions using different end-capped electron-donating groups formed from triphenylamine or OMe-triphenylamine. The influence of π-extension on the charge transfer process is probed by inserting two azomethine groups between acceptor and donor (D-π-A-π-D) groups to make them economically profitable like solar cells. The experimental results available in the literature are combined with our detailed B3LYP/6-311G(d,p) study to find relationships between the structural, and optoelectronic properties of molecules and their performance as HTMs or as donors in organic photovoltaic cells. All investigated molecules were preferential competitors for HTMs in perovskite solar cells because of their excellent HOMO delocalization, lower hole reorganization energies, and high light-harvesting efficiency. They all show a spontaneous solvation process within dichloromethane and have larger Stokes shifts with respect to that of spiro-OMeTAD, which is advantageous for the pore-filling of HTMs for PSCs. The bound electron-hole pairs of the studied molecules can easily escape coulomb attraction by dissociating into negative and positive charges, thus facilitating hole transport, and improving the short-circuit current density. D-A-D type molecules have a blue-shifted absorption maximum in the visible light region and consequently have no overlap with the light-harvesting of the perovskite layer. The π-bridges lengthen the electronic conjugation path of the D-π-A-π-D compounds and introduce more flexibility to the molecule's backbone. Their higher radiative lifetimes make them good candidates for their usage in organic solar cell applications. • Faster hole-transport rate is expected for all investigated molecules. • High light harvesting efficiency and good infiltration and pore-filling of HTMs. • D-A-D molecules do not compete with the light-harvesting of the perovskite layer. • The azomethine connection improves the molecule's solubility. • T 3 , T 6 and T 9 should be good-emitting materials with a high efficiency in the OSCs. [ABSTRACT FROM AUTHOR]

• Faster hole-transport rate is expected for all investigated molecules. • High light harvesting efficiency and good infiltration and pore-filling of HTMs. • MMS1-MMS4 were preferred candidate for HTMs in perovskite solar cells. • MMS4 was the most optimal chemical with remarkable photovoltaic capabilities. This study mainly focuses on modelling and analysis of the reference molecule (M104) as well as four engineered molecules (MMS1-MMS4) as Hole Transport Materials or as light absorbers in Organic Solar Cells. These new molecules are based on thiophene derivatives as acceptor groups, naphthalene as π-bridged groups, and OMeTPA as donor groups. Extensive research was carried out at the molecular level for the studied molecules using DFT and TD-DFT computer simulations to explore their photovoltaic characteristics. All the compounds under investigation were preferred candidate for HTMs in perovskite solar cells because of their superior HOMO delocalization, lower hole reorganization energies, lower chemical reactivity, higher radiative lifetime, higher light-harvesting efficiency, higher dipole moment and spontaneous solvation process inside dichloromethane. The examined molecules' bonded electron-hole pairs can readily split into positive and negative charges to escape coulomb attraction. This increases the short-circuit current density and facilitates hole transport. MMS4 , with its larger maximum absorbance (538.76 nm in dichloromethane), suitable structural features and lower bandgap (2.82 eV), was the most optimal chemical with remarkable photovoltaic capabilities. In conclusion, this work makes a strong case for the synthesis of these high-performing materials by researchers for use in subsequent investigations. [ABSTRACT FROM AUTHOR]