Preparation And Properties Of Gr/X-QDs/Si Solar Cells

Graphene/silicon（Gr/Si）Schottky barrier solar cells are a part and parcel for the harvesting of solar energy and have been gaining favor for their capability in low-cost solution-processing.The interfacial barrier between graphene and silicon has been thrown the spotlight on reducing excessive carrier recombination while accelerating separation processes of photo-generated carriers at interface then powering performance of Gr/Si solar cells,but an rigorous thickness（～2 nm）hard to come by brings complicated as well as costly to bear on processing technique.In this paper,three different quantum dots（X-QDs,X=Cd S,Si,C）materials were used to modify the Gr-Si interface,and a variety of device structures were constructed.The application of interface engineering with X-QDs film as modified barrier layer in Gr/Si-based solar cells was preliminarily explored.The results are as follows:（1）The traditional Cd SQDs materials were prepared,and the Cd S-QDs films were prepared at the Gr-Si interface by spin-coating method,the Gr/Cd SQDs/Si solar cell was successfully constructed.The introduction of Cd S-QDs film optimized the Gr-Si interface,and the performance of the device was improved,the overall efficiency was 2.63%,which was 1.8 times that of the Gr/Si solar cell.（2）Si QDs solution was prepared at room temperature with HF/HNO₃system as etching solution.After optimizing the performance of Si QDs solution,Si-QDs films were prepared at Gr-Si interface.After modification,the photoelectric conversion efficiency of Gr/Si based solar cells was 5.68%.（3）CQDs films were used to modify the Gr-Si interface.Thanks to its unique band structure and charge transfer characteristics,CQDs plays a dual role of electronic blocking and hole transfer in Gr/CQDs/Si solar cells,reducing the J₀of solar cells and increasing the V_OC,thus improving the overall performance of the device.After adjusting the thickness of CQDs films and the size of CQDs,and spin-coating Ti O₂antireflection coating,the Ti O₂/Gr/CQDs/Si solar cell finally achieved 9.97%photoelectric conversion efficiency under AM 1.5G irradiation.