Investigation on the incorporation of quantum dot thin film layers in the organic and inorganic solar cell structures

Candan, İdris
Thin films based photovoltaic solar cell technologies have the Shockley-Queisser limit for maximum efficiencies and these cells can only collect photon in the specific energy range due to their band gap. New approaches are needed to improve the power conversion efficiency (PCE) of photovoltaic devices. Quantum dots (QDs) thin film layer inside any device structure is particularly attractive candidates to increase the PCE of solar cells due to their size adjustable band gap values, multiple exciton generation (MEG) properties. Among the QDs, lead sulfide (PbS) has high photo sensitivity in the infrared (IR) region of electromagnetic spectrum and can be produced with the band gap values in the range of 0.7 to 2.1 eV. Therefore, PbS QD is the material which can be used as a thin film layer in traditional solar cell device architecture to collect photons, having energies in the near IR region which are normally not collected by the devices.  In this study, a new method for increasing the PCE of organic and inorganic solar cells by using QDs thin film layer inside the device structure is discussed. Lead sulfide quantum dots (PbS QDs) thin film layers are separately located inside organic and inorganic devices. The polycrystalline chalcopyrite CuIn1-x GaxSe2 (CIGS) thin films as an inorganic semiconductor and a blend of Poly (3-hexylthiophene-2, 5-diyl) and poly (6, 6-phenyl C61-butyric acid methyl ester) (P3HT:PCBM) as an organic semiconductor are chosen to cooperate with QDs thin film layer for the production of light converting devices. To determine the contributions of PbS QDs thin film layer inside the devices, the optical, structural, morphological, electrical measurements were performed by using the transmission, absorbance, XRD, Raman spectroscopy, SEM, TEM, photoluminescence (PL), photoconductivity, Hall effect, external quantum efficiency (EQE), current–voltage (I-V), capacitance-voltage (C-V), and impedance spectroscopy measurements.


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Citation Formats
İ. Candan, “Investigation on the incorporation of quantum dot thin film layers in the organic and inorganic solar cell structures,” Ph.D. - Doctoral Program, Middle East Technical University, 2016.