A Route to Phase Controllable Cu(2)ZnSn(S(1−x)Se(x))(4) Nanocrystals with Tunable Energy Bands

Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals are an emerging family of functional materials with huge potential of industrial applications, however, it is an extremely challenging task to synthesize Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals with both tunable energy band and phase purity. Here we show that a green and economic route could be designed for the synthesis of Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals with bandgap tunable in the range of 1.5–1.12 eV. Consequently, conduction band edge shifted from −3.9 eV to −4.61 eV (relative to vacuum energy) is realized. The phase purity of Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals is substantiated with in-depth combined optical and structural characterizations. Electrocatalytic and thermoelectric performances of Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals verify their superior activity to replace noble metal Pt and materials containing heavy metals. This green and economic route will promote large-scale application of Cu(2)ZnSn(S(1−x)Se(x))(4) nanocrystals as solar cell materials, electrocatalysts, and thermoelectric materials.