Development of solar cells[edit]
CZTS was first created in 1966[10] and was later shown to exhibit the photovoltaic effect in 1988.[11] CZTS solar cells with efficiency up to 2.3% were reported in 1997, as well as CZTSe devices.[12] The solar cell efficiency in CZTS was increased to 5.7% in 2005 by optimizing the deposition process.[13] A bifacial photoelectrochemical device, using CZTS absorber material and transparent conducting back contact was reported in 2011,[14] which can produce photocurrent on either side of illumination. Recently, it has been demonstrated that sodium has an enhancing effect on the structural and electrical properties of CZTS absorber layers.[15] These improvements, alongside the beginnings of CIGS production on a commercial scale in the mid-2000s catalyzed research interest in CZTS and related compounds.
Since 1988 CZTS was considered as an alternative to CIGS for commercial solar cell systems. The advantage of CZTS is the lack of the relatively rare and expensive element indium. The British Geological Survey Risk List 2011 gave indium a "relative supply risk index" of 6.5, where the maximum was 8.5.[16]
In 2010, a solar energy conversion efficiency of about 10% was achieved in a CZTS device.[17] CZTS technology is now being developed by several private companies.[18] In August 2012, IBM announced they had developed CZTS solar cell capable of converting 11.1% of solar energy to electricity.[19]
In November 2013, the Japanese thin-film solar company Solar Frontier announced that in joint research with IBM and Tokyo Ohka Kogyo (TOK), they have developed a world-record setting CZTS solar cell with a 12.6% energy conversion efficiency.[20]