Environmental-benign Group IV (Si, Ge, Sn) nanomaterials for solar cells, thermophotovoltaic (TPV) cells, and infrared photodetectors

Environmental-benign Group IV (Si, Ge, Sn) nanomaterials for solar cells, thermophotovoltaic (TPV) cells, and infrared photodetectors are being used to address the issue of sustainability as, in the case of solar cells, it is highly desirable to use naturally abundant, environmentally-friendly materials. Currently Si, CdTe and CuInGaSe2 (CIGS) are dominating solar cell materials. Although thin-film CdTe and CIGS solar cells offer higher efficiency their Si rivals, the rarity of Cd, In, and Se elements makes it impossible for them to meet a meaningful portion of global energy needs. The toxicity of Cd also raises environmental concern. By comparison, Group IV materials (Si,Ge,Sn) are very attractive due to their high abundance and low toxicity. Furthermore, (Si,Ge,Sn) alloys and nanostructures have already demonstrated many interesting properties surpassing Si, such as wide range of band gap tenability and direct gap behavior. These properties can potentially lead to better performance than CdTe and CIGS cells. We are investigating material growth, defect passivation, and band-engineering of these environmental-benign Group IV nanomaterials for solar cells and thermophotovoltaic (TPV) cells (direct conversion of thermal radiation to electricity). Similarly, in mid and far infrared photodetectors the dominant HgCdTe material may also be substituted by environmental benign, cost-effective GeSn or Sn nanostructures to achieve IR sensing and night vision.

Faculty contact: Jifeng Liu