Sn-doping for p-type Sb 2 Se 3 absorber solar cells Theodore Hobson 1 , Huw Shiel 1 ,Christopher N. Savory 2 , Jack E. N. Swallow 1 , Bhaskar Das 3 , Leanne A. H. Jones 1 , Matthew J. Smiles 1 , Pardeep K. Thakur 4 ,Tien-Lin Lee 4 , Chris Leighton 3 ,David O. Scanlon 2 , Vinod R. Dhanak 1 ,Ken Durose 1 , Tim D. Veal 1 ,and Jonathan D. Major 1 1 University of Liverpool, UK, 2 University College London, UK, 3 University of Minnesota, United States, 4 Harwell Science and Innovation Campus, UK Antimony selenide (Sb 2 Se 3 ) is a promising absorber material for use in photovoltaics, having achieved 9.2% power conversion efficiency [1] and exhibiting self-healing benign grain boundaries [2]. However, few studies report intentional doping of the absorber. We previously reported that our Sb 2 Se 3 films are n-type from unintentionally incorporated chlorine; these produced isotype n-type heterojunction solar cells with power conversion efficiency of 7.3% [3]. Here we show that bulk crystals of Sb 2 Se 3 exhibit p-type conductivity when doped with tin. The conductivity type and transport properties were measured by hot probe, capacitance- voltage profiling and Hall effect measurements and further confirmed by photoemission measurements of the valence band maximum to Fermi level separation versus depth by combining ultraviolet, x-ray, and hard x-ray photoemission spectroscopy. Near-surface band bending could thereby be determined by solving the Poisson equation to model the photoemission results. The challenges of determining the carrier-type of a low carrier concentration absorber material are described, along with the benefits of using multiple characterization techniques. The viability of using tin for p-type doping of Sb 2 Se 3 for device applications is discussed in light of the experimental results and also density functional theory calculations of the formation energy of Sn dopants and native defects versus Fermi level in the limits of Sb- and Se-rich chemical potentials. References 1. Z. Li, X. Liang, G. Li, H. Liu, H. Zhang, J. Guo, J. Chen, K. Shen, X. San, W. Yu, R. E. I. Schropp, and Y. Mai, 9.2%-Efficient Core-Shell Structured Antimony Selenide Nanorod Array Solar Cells. Nat. Commun. 10 (2019) 125. 2. Rhys E. Williams,Quentin M. Ramasse,Keith P. McKenna,Laurie J. Phillips,Peter J. Yates,Oliver S. Hutter,Ken Durose, Jonathan D. Major,andBudhika G. Mendis, Evidence for Self-healing Benign Grain Boundaries and a Highly Defective Sb 2 Se 3 -CdS Interfacial Layer in Sb 2 Se 3 Thin-Film Photovoltaics, ACS Appl. Mater. Interfaces 12 (2020) 21730–21738. 3. Theodore D. C. Hobson,Laurie J. Phillips,Oliver S. Hutter,Huw Shiel,Jack E. N. Swallow,Christopher N. Savory,Pabitra K. Nayak,Silvia Mariotti,Bhaskar Das,Leon Bowen,Leanne A. H. Jones,Thomas J. Featherstone,Matthew J. Smiles,Mark A. Farnworth,Guillaume Zoppi,Pardeep K. Thakur,Tien-Lin Lee,Henry J. Snaith,Chris Leighton,David O. Scanlon,Vinod R. Dhanak,Ken Durose, Tim D. Veal,and Jonathan D. Major, Isotype Heterojunction Solar Cells Using n-type Sb 2 Se 3 Thin Films, Chem. Mater. 32 (2020)2621–2630.
P08
© The Author(s), 2022
Made with FlippingBook Learn more on our blog