Preparation Of Materias For (Cu_1-xM_x)₂ZnSn?S,Se?₄ Thin Film Solar Cells With Solution Method In Air Atmosphere

Cu,Zn,Sn,S,Se are earth-abundant and nontoxic as component elements of Cu₂ZnSn?S,Se?₄?CZTSSe?.Furthermore,they are environmentally friendly,low-cost and non-toxic,so it has great advantages in terms of raw materials.In addition,CZTSSe has a similar structure and electronic properties with CIGSSe with high power conversion effiiency,which makes it the next best candidate as a supplement to CIGSSe.At present,many researchers use solution method to prepare CZTSSe thin films due to its low cost simple operations.Up to now,an excellent power conversion effiiency of 12.6%for CZTSSe solar cell has been achieved with hydrazine-based solution method.However,hydrazine is explosive and highly toxic,which limits its practical potential and scale CZTSSe module production.As a consequence,developing non-toxic systems has becoming a vital work.As is known to all,water is the the most green and low-cost solvent,so aqueous solution is considered as an ideal approach of obtaining metal chalcogenide semiconductor thin films.Ammonium thioglycolate is a main ingredient of biopharmaceutical raw materials and chemical wave fluids with its non-toxic and safey.Fabricatiing of thin film materials with water-based solution in air atmosphere has great advantages in the cost and operation of thin films undoubtedly.We adjusted chemical compositon of CZTS precursor solution.and obtained higher quality CZTSSe thin film.The main contents of this work are descried as follows.?1?Prepare high-quality Cu₂ZnSnS₄ thin films by using a green water-based system.CZTS precursor solution was obtained by dissolving CuO,ZnO,and SnO into a mixture of ammonium thioglycolate and ammonia aqueous solution.Then,CZTSSe thin films were prepared through spin-coating and preheating process in air atmosphere and selenization.Finnaly,we get the device of an efficiency of 6.1%.?2?Improving the power conversion efficiency of the solar cells by introducing Ag element.In order to achive this goal,we introduce Ag element into the CZTS precursor films to partially replace the Cu element to suppress Cu _Znn defects and increase the open circuit voltage.The power conversion efficiency of solar cells was improved to 7.38%by the adjustment of Ag/?Ag+Cu?ratio.?3?We optimize chemical compositon of CZTS precursor solution,with Cu,Zn,and Sn as the raw materials.After spin coating pretreatments in air atmosphere,high-temperature selenization,and assembly f devices in air atmosphere,we successfully fabricate CZTSSe thin-film solar cells with power conversion fficiency of 1.2%.