New publication: Impact of Ordered Vacancy Compounds on Wide-Gap ACIGS Solar Cells
JV characteristics a) and corresponding EQE spectra b) of the three solar cells samples investigated in this work.
A groundbreaking study by SITA researchers, published in Solar RRL, explores how ordered vacancy compounds (OVCs) influence minority carrier collection in wide-gap (Ag,Cu)(In,Ga)Se₂ (ACIGS) solar cells. The research investigates the role of stoichiometry in shaping the carrier collection efficiency of these next-generation photovoltaic devices.
Three ACIGS absorber samples with varying ([Ag]+[Cu])/([In]+[Ga]) ratios (I/III) were analysed:
Highly off-stoichiometric (I/III = 0.31): Predominantly OVC bulk phase with isolated chalcopyrite patches.
Moderately off-stoichiometric (I/III = 0.77): OVC patches concentrated at the front and back interfaces.
Near-stoichiometric (I/III = 0.94): Minimal, isolated OVC patches.
The team used advanced synchrotron-based X-ray fluorescence (XRF) combined with X-ray beam-induced current (XBIC) to measure nanoscale performance at a 55-nm resolution. Results showed that OVC phases significantly limit carrier collection, adversely affecting the short-circuit current density in highly off-stoichiometric absorbers. Additional insights from transmission electron microscopy and electron-beam induced current analyses confirmed these findings.
This research highlights the importance of stoichiometric precision in optimising ACIGS solar cell efficiency, offering valuable insights into material engineering for wide-gap solar technologies.
For further details, read the full article here.