A New Hole Transport Material for Efficient Perovskite Solar Cells With Reduced Device Cost (Solar RRL 1∕2018)

Abstract

A new and low-cost hole selective material, 2,6,14-tris(5’-(N,N-bis(4-methoxyphenyl) aminophenol-4-yl)-3,4-ethylenedioxythiophen-2-yl)-triptycene, i.e. TET, for efficient perovskite solar cells (PVSCs) has been synthesized and demonstrated in article No. 1700175. As a 2,2’,7,7’-Tetrakis(N,N’-di-p-methoxyphenylamine)-9,9’- spirobifluorene (spiro-OMeTAD) derivative, TET inherits excellent optoelectronic properties and overcomes the major shortfalls of spiro-OMeTAD. Planar PVSCs with TET hole selective layers (HSLs) have achieved a maximum power conversion efficiency (PCE) of 19.1% under reverse voltage scan and steady-state efficiency of 18.6%, comparable with those (19.5% PCE and 19.0% steady-state efficiency) of PVSCs using spiro-OMeTAD HSLs. Importantly, these efficient PVSCs used very thin TET HSLs (about 30 nm) without the need of oxygen doping. Considering the lower lab synthesis and purification cost ($123/g vs $500/g) and thinner HSL (30 nm vs 200 nm), the cost for TET on a unit area of one device is significantly lower (25 times) than that for high-purity spiro-OMeTAD.