Postdoctoral Fellowship: CREST-PRP: Investigation and design of Molecular Spintronic photovoltaic devices via Raman Spectroscopy

The CREST Postdoctoral Research Program (CREST-PRP) provides two years of support for research, training, and mentoring experiences for individual early career scientists at active CREST Centers. The goal of the CREST-PRP is to increase the STEM workforce presence of individuals who are members of groups underrepresented in STEM fields. CREST-PRP awards recognize investigators with significant potential and support their research experiences to broaden their perspectives, facilitate interdisciplinary interactions, and prepare CREST-PRP scholars for positions of leadership within the scientific community.

The research project “CREST-PRP: Investigation and Design of Molecular Spintronic Photovoltaic Devices Via Raman Spectroscopy” is in direct alignment with the CREST-PRP goals. Submitted by a postdoctoral researcher affiliated with the CREST Center for Nanotechnology Research and Education (CNRE) housed at the University of the District of Columbia, the project will focus on the development of a new type of solar cell that is superior to typical silicon-based solar cells in terms of efficiency, cost, and sustainability.

Building on the foundational work in this emerging solar cell science already occurring at the CNRE, this project will take advantage of the spin property of electrons to generate spin-based solar cells developed from inexpensive, Earth-abundant materials like iron and nickel, making them cheaper and recyclable. The proposed research will advance solar cell science by providing insights into the fabrication of a large area solar cell capable of generating a substantial photocurrent.

The optical activity under investigation in this project holds potential to promote other innovations in light harvesting materials, optical sensors, and novel metamaterials. Further, this project will provide training and mentorship to a postdoctoral researcher, enhancing the scholar’s skills as a researcher and principal investigator. The project’s proposed research also aligns with the CHIPS Act goal to bolster semiconductor research training to maintain American competitiveness in the global semiconductor industry.

The Magnetic Tunnel Junction Molecular Spintronic Devices (MTJMSDs) utilized in this research are constructed by linking the ferromagnetic electrodes of a magnetic tunnel junction (MTJ) with an organometallic metal cluster (OMC) or a single molecule magnet (SMM) bridging molecule along the exposed edges of the device. The paramagnetic OMC and SMM molecules create strong exchange coupling between the ferromagnetic electrodes at room temperature.

Previous research conducted at the CNRE has shown that the TaCoNiFe/AlOx/NiFe MTJMSD can generate a reproducible photocurrent and provided evidence of the molecules’ transformative impact on the ferromagnetic metal electrodes using various magnetic and optical experimental methods. This study will include a variety of paramagnetic molecular bridges, ferromagnetic electrode compositions, and insulator thicknesses.

Raman studies also indicate that the MTJMSDs ferromagnetic electrodes respond to visible light radiation; this factor will allow the use of Raman spectroscopy to investigate the spatial range of the photovoltaic effect on the MTJMSD cross-junction area. Findings will be used to fabricate a large area (1 cm2) solar cell based on the optimal molecule/electrode/spatial orientation observed in the studied MTJMSDs.

Limited research has been conducted on this spin-based photovoltaic effect. However, the development of spin-based solar cells may lead to significant cost savings in solar cell production due to the lower cost of materials and manufacture compared to traditional silicon-based devices.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.