Enhancing broadband absorption and photocurrent generation in carbon dots via P3HT integration

The growing interest in carbon dots (CDs) arises from their diverse applications and unique properties. This study addresses challenges in CDs for photodetector (PD) applications, specifically surface defects and trap states hindering efficient charge transport. CDs/P3HT composites were prepared to overcome these issues by incorporating CDs in a poly(3-hexylthiophene) (P3HT) matrix. Broad absorption in spectroscopic characterization revealed its utility in fabricating a broadband PD. The CDs/P3HT PD displays a remarkable broadband photoresponse, spanning both UV and visible regions. The CDs and P3HT are effectively combined via non-covalent π-π interactions constituted by their conjugated systems. The π-π interaction increases electron delocalization and facilitates efficient charge transfer due to band alignment at the junction interface. Hence, fabricated CDs/P3HT PD demonstrated enhanced photocurrent compared to pure CDs, exhibiting high responsivity of 6.12 × 10⁻³ AW⁻¹ and detectivity of 0.69 × 10⁹ Jones. This study highlights the potential of CD/P3HT composites for broadband photodetector applications with enhanced photoelectric conversion.