Samsung Advanced Institute of Technology

Developing light absorbing organic molecules with calculated oscillator strength (f) that estimates the probability of radiative electronic transition of a single molecule has been widely investigated in the field of organic photoelectric devices such as organic photodiodes (OPDs). Most of photoelectric devices, however, are made of organic thin films rather than a single organic molecule. Herein, the molecular volume was considered as one of critical parameters for designing organic molecules. Newly designed three organic molecules Et-H, Me-Me, Me-H having similar oscillator strengths with different molecular volumes were calculated and synthesized as a proof-of-concept and their experimental absorption properties and organic photodiode performances were investigated. The Me-H having smallest molecular volume and highest molecular packing density shows the highest absorption coefficient in organic thin film and shows the highest External Quantum Efficiency (EQE) of OPD performance.