Solution-processed Cu2ZnSnS4 nanoparticle film as efficient hole transporting layer for stable perovskite solar cells

Compact Cu2ZnSnS4 (CZTS) nanoparticle films are in-situ prepared on ITO-coated glass by a novel molecular precursor solution method at a low temperature (300 degrees C) and a short annealing time. The CZTS films exhibit a band gap of 1.48 eV and absorption coefficient of > 10(4)cm(-1). It is found that the performance of CH3NH3PbI3 perovskite solar cells with CZTS film as hole transporting material (HTM) strongly depends on CZTS thickness due to that its absorption of photons significantly limits the photon-to-electron transfer below 550 nm, and the CZTS film thinner than 100 nm is a more effective HTM for efficient MAPbI(3)-based solar cells; furthermore, the CZTS/MAPbI(3) solar cells are much more efficient and stable than the counterpart devices with poly(3,4-ethylenedioxy-thiophene):poly(styrene sulfonate) as HTM.