Spectroscopic Characterization of Colloidal PbS Quantum Dot Solar Cells (2015)

Undergraduate: Cora Went

Faculty Advisor: Rene Lopez
Department: Physics & Astronomy

---

If solar energy is to lead a global transition to renewable energies, researchers must innovate solar cell technologies that are more cost-effective and more efficient. Colloidal quantum dot (CQD) solar cells have the potential to meet both requirements. Colloidal quantum dots are semiconductor particles that are so small that they develop unique properties. For example, it is possible to change the wavelength of light that a quantum dot absorbs just by changing its size. CQD solar cells can employ quantum dots tuned to absorb different wavelengths of sunlight, meaning that they absorb a large percentage of the solar spectrum, which translates to high efficiency. Furthermore, CQD solar cells can be processed into thin films from the liquid phase, which is an inexpensive processing method. The Lopez laboratory explores different structures for lead sulfide (PbS) CQD solar cells both theoretically and experimentally. I will diagnose the poor experimental performance of PbS CQD solar cells by using a technique called photovoltage transient spectroscopy to quantify the amount of defects in these devices. By collecting data from PbS solar cells produced using different processing methods and different structures, I intend to determine which factors during solar cell processing contribute to higher amounts of defects.