Nitrogen-doped graphene quantum dots/ polyvinyl alcohol nanocomposite for photon management: Application in CIGS photovoltaic cells

• Published in: Optical materials 2024-05, Vol.151, p.115384, Article 115384
• Main Authors: Alshahrani, Thamraa, Khan, Firoz, Al-Rasheidi, Masoud, Fareed, Imran, Majid, M. Abdul, Kim, Jae Hyun
• Format: Article
• Language: English
• Subjects: CIGS PV cells; Nitrogen doped graphene quantum dots; Photon down converting layer; Polyvinyl alcohol
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2024.115384

The efficiency (η) of copper indium gallium selenide (CIGS) solar cells has been hampered by absorption losses that happen within the ZnO and CdS layers. A photon downconversion layer created from polyvinyl alcohol (PVA) and nitrogen-doped graphene quantum dots (NGQDs) composite (NGQDs/PVA) was implemented on the top of the cell to overcome this obstacle. Notably, the NGQDs/PVA layers, prepared at spin speeds of 3000, 4000, and 5000 rpm, exhibited optimal characteristics, demonstrating superior light absorption at low wavelengths along with elevated transmittance at longer wavelengths. The η was found to be highest for the layer prepared at 4000 rpm, accompanied by elevated values of short-circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF). Consequently, Cell #2 incorporating the champion NGQDs/PVA layer outperformed all other CIGS photovoltaic cells, showcasing an impressive enhancement of 8.96 % in Jsc, 1.62 % in Voc, 2.03 % in FF, and an overall η of 11.51 %. This champion cell significantly improves the performance of CIGS photovoltaics. •In-situ synthesis and nitrogen doping of graphene quantum dots were accomplished in a single step.•Polyvinyl alcohol (PVA) embedded with nitrogen-doped graphene quantum dots (NGQDs) was employed as a down converting layer.•Optimal NGQDs/PVA down converting layers display the best optical characteristics for CIGS solar cells.•The use of an NGQDs/PVA down converting layer increased the efficiency of a CIGS solar cell by 11.51%.•Champion NGQDs/PVA layer outperforms CIGS cells, advancing photovoltaic technology.