EAGER: Interface Engineering for Low-Temperature Process and Stable Organometal Perovskite Solar Cells

University Of Washington, Seattle WA

Investigators

Abstract

Photovoltaic (PV) technology is a promising method to convert sustainable solar energy into electricity. In order to further lower the cost of solar electricity, increasing efficiency of solar cells, and therefore solar cell modules, becomes more critical because the same power target can be reached with the installation of fewer modules. Recently, organometal halide perovskites have attracted considerable attention as promising PV materials because of the rapid increase in single-junction record efficiencies to exceed 20%, their simple device structures, and the possibility for roll-to-roll low-cost manufacturing on flexible substrates. However, achieving high performance via a low-temperature manufacture process and long-term solar cell stability is still challenging for solar cells based on organometal halide perovskites. This research project seeks to gain fundamental knowledge supporting the discovery of new solar cell interface materials that will have greater stability towards moisture and air while retaining high efficiency. The project is also providing research opportunities for freshmen from the Clean Energy Alliances for Learning and Vision for Underrepresented Americans (ALVA) program and leveraging the research results for the outreach program of Introduce A Girl to Photonics Fair. The fundamental knowledge gained from these materials will make significant impacts on the fields of photovoltaics, optoelectronics and new semiconductor materials. The objective of this research project is to research new hole transport layer (HTL) materials to improve the performance and stability of perovskite solar cells by introducing internal dipoles and by manipulating the morphology of perovskite films. The new HTL materials utilize poly (3, 4-ethylenedioxythiophene) (PEDOT) as a hole transport backbone while different functional group side chains offer to form dipole that could modify the band energy alignment. By modifying the band energy alignment of the HTL structure and the morphology of the perovskite layers, it is hypothesized that an improvement in charge transport and collection as well as device stability will result. The PEDOT-based HTL materials are being synthesized and the electronic, optical and structural properties of HTL thin films fabricated at low temperatures are being investigated. The new PEDOT-based HTLs are being deployed in planar p-i-n structure perovskite solar cells and the device performance and stability are being tested. Organometal halide perovskites exhibit a broad range of band gap enabling the possibility to make highly efficient single-junction and tandem solar cells. This research project could transform photovoltaic technology and make it possible to commercialize perovskite-based photovoltaic technology with competitively low cost.