The Renaissance of Iron Pyrite Photovoltaics: Progress, Challenges, and Perspectives

Abstract

Pyrite has long been proposed as a green solar cell material. Even with its promising properties, studies on pyrite have lagged behind many other semiconducting materials. Unanswered questions about the affects of defects and how to grow pure crystalline material still exist. With the rise of nanochemistry and more powerful computational methods, pyrite is seeing an explosion of new studies. This chapter first presents pyrite and its green promise as a material, followed by the materials characteristics. It then moves into synthesis of pyrite, starting with old methods and then transitioning into different methods of nanocrystal creation. Finally, photo-devices created out of pyrite materials are discussed. The chapter then wraps up with a summary and what still needs to be done for pyrite to achieve its golden status.

Electronic Dynamics in Natural Iron Pyrite Studied by Broadband Transient Reflection Spectroscopy

“…25 The promise of such a strong and readily available absorber has so far been met with dismal performance. Pyrite photovoltaics routinely achieve less than 200 mV open-circuit voltage (V OC ), 11,12 far lower than predicted, presumably due to some combination of deep defect states as well as intrinsic and defect surface states. 11,26−29 These same effects would most likely limit photocatalytic applications; however, this field is still in its infancy.…”

“…4,5 Such properties render pyrite a suspect in the origin of life on earth 6−8 and an extremely intriguing material for application in sustainable energy technologies such as photovoltaics 3,9−12 and photocatalysis. 13,14 In addition to these, more suggested applications of iron pyrite continue to come forth, including broadband photodiodes sensitive in the near IR, 12,15 inorganic sensitizers for solar cells, 16,17 counter electrodes in dye-sensitized solar cells, 18−21 electrocatalysts, 22−24 and photocapacitors. 25 The promise of such a strong and readily available absorber has so far been met with dismal performance.…”

“…In light of these challenges, much of the current pyrite research is focused on developing nanostructured and/or composite materials, and modest successes have been achieved. 12,23,30 Despite this progress, the band structure of 35 The inset shows a zoomed-in region near the Fermi level. Though the band gap may be lower, the onset of optical absorption is consistently measured to be 0.9 eV.…”

“…Iron pyrite (FeS 2 ) is one of the most abundant minerals in the earth’s crust, is extremely cheap to extract, , and has a bandgap and absorption coefficient that allow for a penetration depth (1/α) around 20 nm throughout the visible spectrum . Small organic molecules have also been shown to adsorb readily on its surface. , Such properties render pyrite a suspect in the origin of life on earth − and an extremely intriguing material for application in sustainable energy technologies such as photovoltaics ,− and photocatalysis. , In addition to these, more suggested applications of iron pyrite continue to come forth, including broadband photodiodes sensitive in the near IR, , inorganic sensitizers for solar cells, , counter electrodes in dye-sensitized solar cells, − electrocatalysts, − and photocapacitors …”

Nanocrystalline Pyrite for Photovoltaic Applications

“…Development of synthetic techniques to various nanostructured materials is potentially worthwhile in photovoltaic applications. In the last ten years, solution‐processed (colloidal) pyrite thin films comprising nanocrystals have demonstrated excellent optoelectronic performance because of the quantum confinement effect summarized in a chapter by Alec et al . Mostly pyrite thin films show low majority carrier concentrations ∼10 18 cm −3 .…”