Investigation of the Selectivity of Carrier Transport Layers in Wide‐Bandgap Perovskite Solar Cells

Journal Article · Mon May 03 00:00:00 EDT 2021 · Solar RRL

DOI:https://doi.org/10.1002/solr.202100107· OSTI ID:1781212

Kavadiya, Shalinee ^[1]; Onno, Arthur ^[1]; Boyd, Caleb C. ^[2]; Wang, Xingyi ^[1]; Cetta, Alexa ^[1]; McGehee, Michael D.  ^[3]; Holman, Zachary C.  ^[1]

---

1. School of Electrical, Computer and Energy Engineering Arizona State University Tempe AZ 85287 USA
2. Materials, Chemical, and Computational Science National Renewable Energy Laboratory Golden CO 80401 USA, Department of Materials Science and Engineering Stanford University Stanford CA 94305 USA
3. Materials, Chemical, and Computational Science National Renewable Energy Laboratory Golden CO 80401 USA, Department of Chemical and Biological Engineering University of Colorado Boulder CO 80309 USA

Excellent contact passivation and selectivity are prerequisites to realize the full potential of high‐material‐quality perovskite solar cells, first to maximize the internal voltage (or quasi‐Fermi‐level separation) iV within the absorber, then to translate this high internal voltage into a high external voltage V . Experimental quantification of contact passivation and selectivity is, thus, key to improving device performance. Here, open‐circuit measurements of iV _oc and V _oc , combined with surface photovoltage measurements, are used to systematically quantify the passivation—using iV _oc as a metric—and the selectivity—defined as S _oc  =  V _oc / iV _oc —of a range of common carrier transport layers to wide‐bandgap (1.67 eV) perovskite absorbers. The resulting solar cells suffer from large voltage deficits, particularly when NiO _x is used as the hole transport layer, even though it provides better passivation than its polymer‐based counterparts (PTAA and PTAA/PFN). This indicates a poor selectivity of NiO _x ( S _oc  < 0.81 for NiO _x ‐based devices), whereas devices using polymer‐based hole transport layers exhibit high selectivity ( S _oc  = 0.94–0.95). In agreement with recent reports, this low selectivity is attributed to the formation of an interlayer of non‐perovskite material with high resistance to holes at the perovskite/NiO _x interface. These measurements also imply that the selectivity of the C60‐based electron transport layers is relatively good.

• Sponsoring Organization: USDOE
• Grant/Contract Number: EE0008552; EE0008167
• OSTI ID: 1781212
• Journal Information: Solar RRL, Journal Name: Solar RRL Vol. 5 Journal Issue: 7; ISSN 2367-198X
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English