Deep defects limiting the conversion efficiency of Sb2Se3 thin-film solar cells. Issue 6 (31st January 2023)

• Record Type: Journal Article
• Authors: Dong, Shangwei; Li, Guoshuai; Hong, Jin; Qi, Ruijuan; Yang, Shuai; Yang, Pingxiong; Sun, Lin; Yue, Fangyu
• Is Part Of: Physical chemistry chemical physics. Volume 25:Issue 6(2023)
• Page Start: 4617
• Page End: 4623
• Publication Date: 2023-01-31
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp05585f
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Even under Se-rich conditions, the VSe2 -related deep defects still predominate with an activation energy of ∼0.3 eV, largely limiting the efficiency of solar cell structures below ∼7.63% due to the ultrafast capture rate of non-equilibrium carriers. Abstract : Quasi-one-dimensional (Q1D) semiconductor antimony selenide (Sb2 Se3 ) shows great potential in the photovoltaic field, but the photoelectric conversion efficiency (PCE) of Sb2 Se3 -based solar cells has shown no obvious breakthrough during the past several years, of which the intrinsic reasons are pending experimentally. Here, we prepare high-quality Q1D Sb2 Se3 thin films via the vapor transport deposition technique. By investigating the bandedge electronic level structure and carrier relaxation/recombination dynamics, we find that (i) the optimized Se-rich growth conditions can highly improve the crystal quality of the Q1D Sb2 Se3 thin films, the carrier lifetime of which is substantially increased up to ∼8.3 μs; (ii) the Se-rich growth conditions have advantages to annihilate the deep selenium vacancies VSe i ( i = 1 and 3 for non-equivalent Se atomic sites) but is not effective for the deep donor VSe2, which locates at ∼0.3 eV (300 K) below the conduction band and intrinsically limits the PCE value of devices below ∼7.63%. This work suggests that further optimizing the Se-rich conditions to technically eliminate this kind of deep defect is still essential for preparing high-performance Sb2 Se3 film solar cells.