Metal- and Metalloid-Functionalized Diketopyrrolopyrroles for High-Performance Photovoltaics

The current global energy demand has made it urgent to find highly efficient, cost-effective, and lightweight solar technologies. Organic and perovskite-based solar cells have recently emerged as strong alternatives by offering significant advantages over traditional silicon-based solar cells. However, the development of highly efficient photovoltaic materials with tunable optoelectronic properties remains challenging. This review article summarizes the progress in the development of various metal- and metalloid-based diketopyrrolopyrrole (DPP) materials for photovoltaic applications. DPP is a widely used chromophore for preparing efficient semiconducting materials due to its strong electron-accepting ability, broad absorption spectra and high thermal stability, along with a rigid planar backbone, supports π-π stacking and efficient charge transport. This review systematically describes the synthetic design strategies, optoelectronic properties, and device performance of metal- (iron, platinum, iridium) and metalloid- (sulfur, selenium, tellurium, silicon) based DPP materials. A detailed analysis with respect to their structure-property relationships and impact of metal on the device performance is provided. The analysis of various derivatives shows that the nickel-DPP-based ternary devices achieved the highest power conversion efficiency (PCE) of 16.06%, whereas the platinum-DPP binary device gives the highest efficiency of 15.03%. The review emphasizes the importance of integrating various metal- and metalloid elements into DPP to enhance performance. Finally, the review concludes by addressing fundamental challenges and promising future research directions.