Barium copper sulfur fluoride transparent conductive thin films and bulk material
View Patent ↗The present invention is generally directed to a bulk barium copper sulfur fluoride (BCSF) material made by combining Cu 2 S, BaS and BaF 2 , heating the ampoule between 400 and 550 ° C. for at least two hours, and then heating the ampoule at a temperature between 550 and 950 ° C. for at least two hours. The BCSF material may be doped with potassium, rubidium, or sodium. The present invention also provides for a BCSF transparent conductive thin film made by forming a sputter target by either hot pressing bulk BCSF or hot pressing Cu 2 S, BaS and BaF 2 powders and sputtering a BCSF thin film from the target onto a substrate. The present invention is further directed to a p-type transparent conductive material comprising a thin film of BCSF on a substrate where the film has a conductivity of at least 1 S/cm. The substrate may be a plastic substrate, such as a polyethersulfone, polyethylene terephthalate, polyimide, or some other suitable plastic or polymeric substrate.
1. A method of making bulk barium copper sulfur fluoride (BSCF), comprising:
(a) combining Cu 2 S, BaS and BaF 2 in stoichiometric proportions;
(b) heating the combination for a first heating at a temperature between 450 and 500° C. for at least two hours; and
(c) heating the combination for a second heating at a temperature between 600 and 700° C. for at least two hours;
wherein the first heating is for about ten hours, and the second heating is for about 95 hours.
2. A method of making bulk barium copper sulfur fluoride (BSCF), comprising:
(a) combining Cu 2 S, BaS and BaF 2 in stoichiometric proportions;
(b) heating the combination for a first heating at a temperature between 400 and 550° C. for at least two hours; and
(c) heating the combination for a second heating at a temperature between 550 and 950° C. for at least two hours;
wherein the combination of Cu 2 S, BaS and BaF 2 is placed into a vitreous carbon crucible inside an ampoule before heating.
3. The method of claim 1 wherein doped BCSF is fabricated by adding KF, K 2 S, RbF, Rb 2 S, Na 2 S, or NaF with the Cu 2 S, BaS and BaF 2 and adjusting the amount of BaF 2 if a fluoride doping agent is used or the amount of BaS if a sulfide doping agent is used to maintain approximate stoichiometric proportions.
4. The method of claim 2 , wherein doped BCSF is fabricated by adding KF, K 2 S, RbF, Rb 2 S, Na 2 S, or NaF with the Cu 2 S, BaS and BaF 2 and adjusting the amount of BaF 2 if a fluoride doping agent is used or the amount of BaS if a sulfide doping agent is used to maintain approximate stoichiometric proportions.