ELECTRODEPOSITION OF THIN-FILM CELLS CONTAINING NON-TOXIC ELEMENTS

摘要

A structure and method of making a thin-film solar cell is provided. A thin-film solar cell includes a substrate, absorber layer and a buffer layer. The absorber layer is deposited by a single-step bulk electrochemical process, or a multi-layer electrochemical process. The buffer layer is deposited by an electrochemical deposition process such as a multi-layer deposition or an atomic layer deposition. The absorber and buffer layers are non-toxic materials which can include sulfur incorporated during the deposition process or incorporated after deposition by an anneal step.

主权项

1. A method of manufacturing a thin-film cell, the method comprising:
providing a substrate; depositing an absorber layer onto the substrate; and depositing a buffer layer onto the absorber layer, wherein the absorber layer and the buffer layer are made from non-toxic materials; wherein the depositing the absorber layer and the buffer layer is performed using an electrochemical atomic layer deposition process carried out under illumination so as excite electrons from a valence band to a conduction band, wherein the electrons at an edge of the conduction band at a solid/liquid interface are energetically higher than that of a redox potential of S2O32−/ZnS; and wherein the electrochemical deposition process for depositing the buffer layer is carried out by: filling a cell with a zinc solution comprising 1 mM to 1000 mM ZnSO4 buffered with NH3; adjusting a pH of the zinc solution to about 9-12; exposing the absorber layer to a light source; applying a voltage to a substrate located in the cell of about −0.4 V to about −1.5 V with reference to a saturated calomel reference electrode for about 1 to 100 seconds; rinsing the cell for about 1 to 100 seconds using a rinse solution of ammonia buffered solution at a pH of about 9 to about 12, wherein the voltage of about −0.4 V to about −1.5 V is maintained; filling the cell with a gaseous sulfur solution comprising 0.1 mM to 1M Na2S buffered with NH3; adjusting a pH of the sulfur solution of about 9 to about 12; exposing the absorber layer to a light source; applying a voltage to the substrate located in the cell of about −0.4 V to about −1.5 V with reference to the saturated calomel reference electrode for about 1 to 100 seconds; rinsing the cell for about 1 to 1000 seconds using the rinse solution, wherein the voltage of −0.4 V to about −1.5 V is maintained; and repeating the above steps for 1 to 2000 cycles, for each cycle increasing the voltage applied to the electrode by about −0.001 V up to a voltage of about −1 V or by about +0.001 V down to a voltage of about −0.1 V, thereby producing a thin-film of ZnS.