Solar cell production and characterization with CdTe nanomaterial

The increasing need for energy throughout the world, while the rapid reduction of fossil fuels, increases the importance of alternative energy sources. The high cost of the existing silicon and germanium based first generation solar panels, and the fact that the energy generation efficiency of the second generation solar panels, which are available as an alternative, is around 13%, has led to the need to concentrate on third generation solar panels. The third-generation solar panels, which are still in development stage, have already caught the first-generation solar panels in efficiency. Within the third generation solar panels, the Quantum Dot Sensitized Solar Cell (QDSSC) has attracted attention in the past five years. Unique opto-electronic features such as easy machinability, adjustable size and band gap, and Multiple Exciton Generation (MEG) make quantum dots attractive. These characteristics demonstrate that theoretically the energy conversion efficiency for QDSSC can be up to 44%. This work focuses on CdTe QDSSC design. Thesis is divided into 3 basic divisions; Synthesis of CdTe QD, treatment of CdTe QD and design of QDSSC with synthesized CdTe QDs. The hot injection method was used for synthesis of CdTe QD. Photoluminescence Quantum Yield (PLQY) of CdTe QDs, synthesized by the conventional method, was found to be 8.12%. The hot injection method was then modified by the Cannula method and the PLQY value was increased to 25.66%. Furthermore, Full Width Half Maximum (FWHM) of PL pik of CdTe QD was reduced to 27 nm so that the organometallic CdTe QD, which exhibited the highest monodispersity in the literature, was synthesized. Then, the synthesized CdTe QD was subjected to chloride passivation and different amounts of chloride (12-96 CdCl2/nm2) ions were injected into the QD. As a result of the analysis, it was determined that the PLQY value increased to 87.33% with 60 CdCl2/nm2 treatment. The passivization treatment was made 70% reproducible by Cannula method. Furthermore, the duration of the CdTe QD in the oxygen environment has been increased 3 times. After synthesis and treatment, QDSSC design studies were started. At this stage, several healing studies have been performed on CdTe QD size, TiO2 thickness, treatment on FTO / TiO2 surface, attachment of CdTe KN to the surface, redox couple and collecting electrode. As a result of all the optimization processes, FTO/TiCI4/TiO2 (22µm) /TiCI4/36 CdCI2/nm2 CdTe(CI) QD surface was used as photo anode and FTO/Pt surface was used as collecting electrode. I-/I3- redox couple was injected between these two surfaces. For the designed QDSSC, Jsc is 3.223mA/cm2, Voc is 0.821V, filling factor is 57.192% and efficiency is 1.51%. This efficiency is 7.97 times bigger than the similarities work (%0,197) in the literature.