Nanosecond carrier lifetimes in solution-processed enargite (Cu3AsS4) thin films

Abstract

Enargite (ENG) Cu3AsS4 is a promising material for photovoltaic applications due to its constituent earth abundant elements of differing ionic radii, ideal predicted optoelectronic properties, and demonstrated use in a working thin-film solar cell. However, little is known about ENG's defect properties; such knowledge is necessary to assess its potential for future use in high-efficiency devices. One indicator of a material's quality is its photogenerated carrier lifetime, which can be related to its bulk defect properties. Here, we use a combination of time-resolved terahertz spectroscopy and time-resolved photoluminescence to assess carrier dynamics in ENG thin films processed from nanoparticle precursors. The Shockley–Read–Hall (SRH) lifetimes are on the multi-nanosecond scale, which exceed those reported in more mature systems and represent promising values for a candidate photovoltaic material. These results suggest that ENG is worthy of further research and development effort with an eye toward future photovoltaic applications.

Emerging Chalcogenide Thin Films for Solar Energy Harvesting Devices

“…557 Compared to the high-efficiency emerging chalcogenides discussed in Section 3, a relatively long carrier lifetime of >1 ns was observed in Cu 3 AsS 4 using a combination of TRTS and TRPL. 555,558 A preliminary PCE of 0.24% was reported using CdS as the n-type buffer layer; 559 however, it was noted that CdS formed an unfavorable band alignment with Cu 3 AsS 4 , and better results are expected using ZnS as the buffer layer. 555 Cu 3 AsS 4 is also a promising photoferroic material having considerable spontaneous polarization, and it could exhibit a bulk and anomalous photovoltaic effect (that is, a photovoltage higher than the photoabsorber band gap).…”

Solution processed metal chalcogenide semiconductors for inorganic thin film photovoltaics

“…However, despite reasonably high carrier lifetimes from enargite Cu 3 AsS 4 , the resulting solar cells had efficiencies below 1%. 150,153,154 Recently, amine-thiol based molecular precursors were used to successfully alloy Ag into Cu 3 AsS 4 up to Ag/(Ag + Cu) atomic ratios of 0.14, however solar energy conversion efficiencies remained below 1%. 155 The first synthesis of Cu 3 SbS 4 nanoparticles was reported by Van Embden and Tachibana in 2012 and was followed with the synthesis of CuSbS 2 , Cu 3 SbS 3 , and Cu 12 Sb 4 S 13 nanoparticles.…”

“…However, despite reasonably high carrier lifetimes from enargite Cu 3 AsS 4 , the resulting solar cells had efficiencies below 1%. 150,153,154 Recently, amine–thiol based molecular precursors were used to successfully alloy Ag into Cu 3 AsS 4 up to Ag/(Ag + Cu) atomic ratios of 0.14, however solar energy conversion efficiencies remained below 1%. 155…”

Copper-Arsenic-Sulfide Thin-Films from Local Raw Materials Deposited via RF Co-Sputtering for Photovoltaics

“…So far, the highest attained efficiency was 0.49% by Andler et al [30], with an enargitebased PV cell obtained through a heat treatment of copper-sulfide films under an As-and S-rich atmosphere. The low efficiency has been attributed to film porosity, presence of unwanted secondary phases and poor band alignment with the CdS (n-type semiconductor) selective contact [13,30,31].…”