Enhanced Sb₂Se₃solar cell performance through theory-guided defect control

Abstract

Defects present in the absorber layer largely dictate photovoltaic device performance. Recently, a binary photovoltaic material, Sb2Se3, has drawn much attention due to its low‐cost and nontoxic constituents and rapid performance promotion. So far, however, the intrinsic defects of Sb2Se3 remain elusive. Here, through a combined theoretical and experimental investigation, we revealed that shallow acceptors, SeSb antisites, are the dominant defects in Sb2Se3 produced in an Se‐rich environment, where deep donors, SbSe and VSe, dominate in Sb2Se3 produced in an Se‐poor environment. We further constructed a superstrate CdS/Sb2Se3 thin‐film solar cell achieving 5.76% efficiency through in situ Se compensation during Sb2Se3 evaporation and through careful optimization of absorber layer thickness. The understanding of intrinsic defects in Sb2Se3 film and the demonstrated success of in situ Se compensation strategy pave the way for further efficiency improvement of this very promising photovoltaic technology. Copyright © 2017 John Wiley & Sons, Ltd.

Vapor transport deposition of antimony selenide thin film solar cells with 7.6% efficiency

“…Material and device characterization are similar to previous report 1, 2, 11 . XRD of Sb 2 Se 3 films was performed using a Philips X’Pert Pro diffractometer with Cu Kα radiation ( λ  = 1.54 Å).…”

“…As reported by Tumelero et al 44 , the antisite defects dominated the distribution of defects in trichalcogenides due to the similar sizes of the constituent atoms. Our previous simulation also showed that Se Sb and antimony antisite (Sb Se ) are acceptor and donor defects, respectively 11 . Consequently, the E1 defect is most likely associated with the formation of Sb Se antisite defects.…”

“…Our previous ab initio calculation of the intrinsic defects in Sb 2 Se 3 has demonstrated that the dominant acceptor defects are antimony vacancy (V Sb ) and selenium antisite (Se Sb ) defects under Se-rich condition 11 . Therefore, we tentatively attributed H1 and H2 defects to V Sb and Se Sb defects, respectively.…”

“…However, the highest power conversion efficiency (PCE) of Sb 2 Se 3 thin film solar cells with a CdS/Sb 2 Se 3 superstrate configuration is so far 5.6% 2, 4–11 , and with a ZnO/Sb 2 Se 3 superstrate configuration 5.93% 1 . Employing PbS colloidal quantum dots (QDs) as the hole transport layer, as-fabricated device CdS/Sb 2 Se 3 /PbS QDs demonstrated an efficiency of 6.5% 12 .…”

Review of Recent Progress in Antimony Chalcogenide‐Based Solar Cells: Materials and Devices

“…Hall measurements prove that Sb 2 Se 3 films prepared by a fast thermal evaporation method present low conductivities of 10 −7 –10 −6 S cm −1 and a maximum hole concentration of 10 15 cm −3 if deposited in Se‐rich conditions. Transient absorption decay spectroscopy measurements demonstrate that the photocarrier lifetimes of Sb 2 Se 3 films are ≈102 ns . The mobility of Sb 2 Se 3 along the [0 0 1] direction can be as high as 20 cm 2 V −1 s −1 , and the electron diffusion length along the [0 0 1] direction under high illumination is 1.7 µm .…”