Molecular routes to Cu2ZnSnS4: A comparison of approaches to bulk and thin-film materials

A range of xanthates (R'P-3)(2)CuS2COR [R' = Ph, R = Et (1), i-Pr (2), t-Bu (3), t-Amyl (4); R' = PhO, R = Et (5), R' = n-Bu, R = Et (6), Bu-n (7)], M(S2COR)(2) [M = Sn R = Et (8); Zn, R = Et (10), i-Pr (11), n-Pr (12), n-Bu (13), n-Hex (14)], Sn(S2COEt)(4) (9), Zn(S2COEt)(2)center dot TMEDA (15) have been synthesised and their thermal decomposition profiles delineated by TGA. A parallel range of dithiocarbamates (R'P-3)(2)CuS2CN(Me)R [R' = Ph, R = Bu-n (16), Bz (17)], M[S2CN(Me)R](2) [M = Sn, R = Bu-n (18), Bz (19); M = Zn, R = Bu-n (21), Bz (22)] has been similarly assessed. Although precursor combinations have been found from these systems that generate Cu2ZnSnS4 (CZTS) from either a bulk decomposition (1, 8, 10 at 400 degrees C/Ar; Cu2Zn1.02Sn0.74S4.6), from a doctor-bladed film (7, 8, 13 at 400 degrees C/Ar; Cu2Zn12Sn10S3.6 and as nanoparticles (7, 8, 13 in octadecanefoleic acid, 150 degrees C; Cu2Zn10Sn0.7S2.6), attempts to deposit CZTS by aerosol-assisted CVD has proved more challenging and only successful from the dithiocarbamates 16, 18, 21 (350 degrees C; Cu2Zn0.9Sn0.7). As part of this work the crystal structures of 2-5, 8, 16, and the dithiocarbamate decomposition product {Sn[S2CN(Me)Bu-n)](2)S}(2) (20) have been determined.