Thieno[3,4-c]pyrrole-4,6-dione-based small molecules for highly efficient solution-processed organic solar cells

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Organic solar cells (OSCs) offer a promising alternative to conventional photovoltaics.
• Solution-processed small-molecule organic solar cells require efficient donor materials.
• Thieno[3,4-c]pyrrole-4,6-dione (TPD) based molecules are explored for their electronic properties.

Purpose of the Study:

• To design and synthesize novel small molecules for organic solar cells.
• To investigate the structure-property relationships of TPD-based donor materials.
• To evaluate the photovoltaic performance of these molecules in bulk-heterojunction solar cells.

Main Methods:

• Synthesis of BT-TPD and TBDT-TTPD small molecules.
• Characterization of thermal, electrochemical, and optical properties.
• Measurement of charge transport properties (hole mobility).
• Fabrication and testing of small-molecule organic solar cells.

Main Results:

• The synthesized molecules exhibit strong absorption in the 460-560 nm range.
• Low highest occupied molecular orbital levels (-5.36 eV) were observed.
• High field-effect hole mobilities ranging from 1.7-7.7×10⁻³ cm² V⁻¹ s⁻¹ were achieved.
• Power conversion efficiencies (PCEs) as high as 4.62% were obtained in bulk-heterojunction solar cells.

Conclusions:

• BT-TPD and TBDT-TTPD are effective donor materials for solution-processed organic solar cells.
• The TPD core contributes to favorable electronic and optical properties.
• These small molecules represent a viable option for advancing organic photovoltaic technology.