“…27,29 More importantly, they need to be transparent in the visible spectral region when used in semitransparent solar cells and should be cost-effective. The most popular HTMs explored to date for Sb 2 S 3 solar cells are the organic-based P3HT (poly(3-hexylthiophene)), 3,5,22,27 spiro-OMeTAD (2,2 0 ,7,7 0 -tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9 0 -spirobi-uorene), 24,25 PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) 23 and PCPDTBT (poly [2,6-(4,4- 30 Among inorganic materials, NiO x , 31 V 2 O 5 32 and CuSCN:KSCN 6 have been reported as HTMs. For instance, Kim et al have fabricated planar Sb 2 S 3 solar cells with spin coated PEDOT:PSS as the HTM wherein Sb 2 S 3 is deposited using CBD, and have obtained a PCE of 5.8%.…”