Effect of Hole Transport Materials and Their Dopants on the Stability and Recoverability of Perovskite Solar Cells on Very Thin Substrates after 7 MeV Proton Irradiation

The drastic reduction in launch and manufacturing costs of space hardware has facilitated the emergence of commercial space. Radiation-hard organometal halide perovskite solar cells (PSCs) with low-cost and high-efficiency potentials are promising for space applications.High-efficiency PSCs are tested with different hole transport materials (HTMs) and dopants on 175 mu m sapphire substrates under 7MeV-proton-irradiation-tests at accumulated fluences of 10(11), 10(12), and 10(13) protons cm(-2). While all cells retain >90% of their initial power conversion efficiencies (PCEs) after 10(11) protons cm(-2) irradiation, PSCs that have tris(pentafluorophenyl)borane (TPFB) as the HTM dopant and poly[bis(4-phenyl)(2,5,6-trimethylphenyl) amine (PTAA) or PTAA:C8BTBT (C8BTBT = 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene) as the HTM are more tolerant to higher-fluence radiation than their counterparts with the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dopant and the 2,2 ',7,7 '-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9 '-spirobifluorene (Spiro-OMeTAD) HTM. Radiation induces fluorine diffusion from the LiTFSI dopant toward the perovskite absorber (confirmed by depth-resolved X-ray photoelectron spectroscopy) introducing defects. Radiation-induced defects in cells with the TPFB dopant instead are different and can be annealed out by thermal vacuum resulting in PCE recovery. This is the first report using thermal admittance spectroscopy and deep-level transient spectroscopy for defect analyses on proton-irradiated and thermal-vacuum-recovered PSCs. The insights generated are expected to contribute to efforts in developing low-cost light-weight solar cells for space applications.

Automated summary

The reduction in space hardware costs has enabled commercial space to emerge. Radiation-hard organometal halide perovskite solar cells (PSCs) have the potential for low-cost and high-efficiency space applications. The study tested high-efficiency PSCs with different hole transport materials (HTMs) and dopants under proton irradiation, and found that PSCs with specific HTMs and dopants were more tolerant to higher-fluence radiation. The insights gained from this study will contribute to the development of low-cost lightweight solar cells for space applications.