Polyaniline–graphene quantum dots (PANI–GQDs) are considered as an important candidate for applications in photovoltaic cells. In this work, GQDs were prepared using sono-Fenton reagent from reduced graphene oxide (rGO). PANI–GQD hybrid was also synthesized using the chemical in situ polymerization method. The synthesized materials were characterized using UV–visible (UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, current–voltage (I–V) characteristic, thermal gravimetric analysis (TGA), Raman spectroscopy, and X-ray diffraction (XRD). Dynamic light scattering was also used to estimate the lateral size of GQDs. The enhanced visible-light absorbance in the hybrid was confirmed by UV–Vis analysis and the decrease in intensity around 3461 cm−1 in FT-IR spectra was due to the interaction between functional groups of PANI with GQDs. This led to improved thermal stability and conductivity as observed from TGA and I–V analysis, respectively. Moreover, the Raman spectrum for PANI–GQDs showed a decrease in the peak at ~ 1348 and ~ 1572 cm−1 as compared to PANI and GQDs. Similarly, from the XRD profile of PANI–GQDs, a shift in peak was observed due to an alteration in the microstructure. A sandwich device with cell structure glass/ITO/PANI–GQDs/Al was fabricated and its application was tested. Current density–voltage (J–V) curve of the device was measured with a Keithley SMU 2400 unit under an illumination intensity of 100 Wm−2 simulating the AM 1.5 solar spectrum. The hybrid exhibited photovoltaic properties, and 0.857% efficiency was observed in response to the applied voltage. This work suggests that PANI can be used as an alternative material for photovoltaic cells.

Abstract
1 Introduction
2 Experimental methods
    2.1 Chemicals
    2.2 Materials’ synthesis
    2.3 Characterization
    2.4 Results and discussion
    2.5 Efficiency
3 Conclusion
Compliance with ethical standards
References

• Gebremedhin Gebremariam Gebreegziabher(Faculty of Materials Science and Engineering, Polymer Engineering, Jimma University Institute of Technology, Chemistry Department, College of Natural and Computational Science, Mekelle University)
• Assefa Sergawie Asemahegne(Industrial Chemistry, Addis Ababa Science and Technology University)
• Delele Worku Ayele(Chemistry Department, College of Science, Materials Science and Engineering, Bahir Dar University)
• Dhakshnamoorthy Mani(Faculty of Materials Science and Engineering, Polymer Engineering, Jimma University Institute of Technology)
• Rewrewa Narzary(Department of Electronics and Communication Engineering, Tezpur University)
• Partha Pratim Sahu(Department of Electronics and Communication Engineering, Tezpur University)
• Ashok Kumar(Material Research Laboratory, Department of Physics, Tezpur University)