High efficiency and thermally stable ternary all-polymer solar cells achieved by alloyed vinyl-linked polymerized small-molecule acceptors

Abstract

A high power conversion efficiency (PCE) and long-term stability are crucial for the commercialization of allpolymer solar cells (all-PSCs). In this study, we develop two new polymerized small -molecule acceptors (PSMAs) that include vinylene and fluorinated vinylene linkers (PYBO-VH and PYBO-VF, respectively), to achieve all-PSCs with high PCE (> 18.5%) and thermal stability (T80% lifetime > 1800 h at 120 C-degrees). The PYBO-VF with fluorinated vinylene linkers has more planar backbones than PYBO-VH with vinylene linkers. Thus, PYBOVF exhibits an 1.5 -fold increase in electron mobility (u(e) = 4.8 x 10-4 cm(2) V-1 s(-1)) and higher glass transition temperature (Tg = 200 C-degrees) compared with PYBO-VH (u(e) = 3.1 x 10-4 cm(2) V-1 s-(-1) and T-g = 158 C-degrees). As a result, all-PSCs based on PYBO-VF demonstrate superior PCE (17.16%) and thermal stability (T80% lifetime = 2270 h) than those based on PYBO-VH (PCE = 16.44% and T80% lifetime = 1385 h). Importantly, when both PYBO-VH and PYBO-VF are used for constructing ternary all-PSCs, we successfully demonstrate a high-performance and stable all-PSC with a PCE of 18.53% and thermal stability at 120 C-degrees (T80% lifetime = 1840 h). The ternary allPSCs have one of the best performances among all-PSCs reported to date.