Hot-Injection synthesis of PbS quantum dots for applications in colloidal quantum dot solar cells

• Main Authors: Shu-Hua Huang, 黃舒崋
• Other Authors: Ming-Way Lee
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/nk7w5h

碩士 === 國立中興大學 === 奈米科學研究所 === 106 === This study focuses on the synthesis of PbS quantum dots as well as its application in colloidal quantum dot solar cells (CQDSCs). The fabrication of CQDSCs is divided into three parts：(1) Synthesis of PbS quantum dots by chemical hot injection. (2) Deposition of CdS thin films using RF magnetron sputtering. (3) Assembly of solar cells. First, a CdS film was sputtered on FTO glass. Second, a PbS colloidal quantum dot layer was coated on top of the CdS film using the layer-by-layer deposition method. Finally, an Au electrode was deposited to form the electrical electrode. The PbS/CdS forms a P/N-junction heterostructure solar cell. The synthesized material and the structure of the solar cell were characterized by US-VIS spectroscopy, XRD, TEM, SEM and AFM. The thickness of the CdS thin film, determined through SEM cross-sectional images, is about 100 nm. The energy gap (Eg) of CdS, calculated from UV-Vis absorption spectra, is about 2.5 eV. TEM images showed the particle size of PbS quantum dots to be ~ 3.75 nm, The PbS quantum dots show an exciton peak at 1058 nm, corresponding to an Eg of ~ 1.2 eV. The thickness of the PbS film is about 500 nm. Under 100 % sunlight illumination (AM 1.5) of 100 mW/cm2, the PbS CQD solar cell exhibited a power conversion efficiency of 0.26 %, a short circuit density of 3.54 mA/cm2, an open circuit voltage of 0.36 V and a fill factor of 20.54 %. The CQD solar cells showed high stability after repeated testing for eight times over a period of 60 days.