Chemically switchable ultraviolet photoluminescence

Patent metadata

Field	Value
Publication number	US-2017102332-A1
Application number	US-201515128149-A
Country	US
Kind code	A1
Filing date	Mar 23, 2015
Priority date	Mar 26, 2014
Publication date	Apr 13, 2017
Grant date	—

Abstract

The present disclosure pertains to the use of intense, narrow-linewidth surface, chemically-switchable ultraviolet photoluminescence from radiative recombination of the two-dimensional electron liquid with photo-excited holes in complex oxide heterostructures, such as LaAlO 3 /SrTiO 3 (LAO/STO). Such photoluminescence from the interface between the upper and lower layers can be suppressed and restored reversibly under oxidizing and reducing conditions, respectively, as induced by chemisorption and reversal of chemisorption on the exposed surface of the heterostructure's upper member. Making use of this chemically-switchable ultraviolet photoluminescence, the present disclosure provides, inter alia, systems for detection of a chemical species, methods for determining the absence or presence of a chemical species in a sample, optoelectronic devices, and methods for producing optoelectronic devices.

First claim

What is claimed:

1 . A system for detection of a chemical species comprising:
a complex oxide heterostructure comprising an upper member having an exposed surface, a lower member, and an interface between the upper and lower members,
wherein chemisorption of said chemical species at the exposed surface of the upper member produces ultraviolet photoluminescence at the interface between the upper and lower members, and
wherein said upper member has a thickness of up to about 30 unit cells; and,
a sensor for determining the absence or presence of ultraviolet photoluminescence at the interface.

2 . The system according to claim 1 , wherein said chemical species is characterized as donating up to one-half electron per unit cell of said upper member when chemisorbed onto the exposed surface of said upper member.

3 . The system according to claim 1 , wherein said chemical species is characterized as filling an oxygen vacancy on the exposed surface of said upper member.

4 . The system according to claim 1 , wherein said chemical species is a molecule containing an alkali or transition metal and at least one cation that results in chemisorption of H+ on the exposed surface of said upper member.

5 . The system according to claim 1 , wherein said upper and lower members comprise an oxide perovskite.

6 . The system according to claim 1 , wherein said upper member comprises GdTiO 3 , SrVO 3 , LaVO 3 , SrNbO 3 , or LaAlO 3 and said lower member comprises SrTiO 3 .

7 . The system according to claim 1 , wherein said sensor measures the intensity of said ultraviolet photoluminescence, measures the chemisorption coverage on a surface of the upper layer, or both.

8 . A method for determining the absence or presence of a chemical species in a sample comprising:
providing a complex oxide heterostructure comprising an upper member having an exposed surface, a lower member, and an interface between the upper and lower members,
wherein chemisorption of said chemical species at the exposed surface of the upper member produces ultraviolet photoluminescence at the interface between the upper and lower members, and
wherein said upper member has a thickness of up to about 30 unit cells;
contacting the exposed surface of the upper member of said heterostructure with the sample; and, determining whether the interface between the upper and lower members produces ultraviolet photoluminescence following said contacting step.

9 . The method according to claim 8 , further comprising measuring the intensity of any ultraviolet photoluminescence at the interface between the upper and lower members.

10 . The method according to claim 8 , further comprising, if said interface does produce ultraviolet photoluminescence, terminating at least some of said ultraviolet photoluminescence.

11 . The method according to claim 10 , wherein said photoluminescence is terminated using one or more of a laser, a heat pulse, or photoionization.

12 . An optoelectronic device comprising:
a complex oxide heterostructure comprising an upper member having an exposed surface, a lower member, and an interface between the upper and lower members,
wherein said upper member has a thickness of up to about 30 unit cells; and,
a plurality of individual members of a chemical species that is chemisorbed in a patterned array on said exposed surface of the upper member, wherein the chemisorption of each member of said chemical species at the exposed surface produces ultraviolet photoluminescence at a location of the interface that corresponds to the spatial location of each member on said exposed surface.

13 . A plurality of optoelectronic devices according to claim 12 that encodes information when said ultraviolet photoluminescence at the interface of each respective device is read in series.

14 . A method for producing an optoelectronic device comprising:
providing a complex oxide heterostructure comprising an upper member having an exposed surface, a lower member, and an interface between the upper and lower members,
wherein said upper member has a thickness of up to about 30 unit cells;
chemisorbing a plurality of individual members of a chemical species in a patterned array on said exposed surface of the upper member,
wherein the chemisorption of a member of said chemical species at the exposed surface produces ultraviolet photoluminescence at a location of the interface that corresponds to the spatial location of said member on said exposed surface.

15 . The method according to claim 14 , further comprising chemisorbing at least one member of each of two different chemical species, wherein the chemical species respectively produce different intensities of ultraviolet photoluminescence at said interface when chemisorbed onto the exposed surface of the upper member.

16 . The method according to claim 14 , further comprising providing a plurality of said optoelectronic devices that encode information when said ultraviolet photoluminescence at the interface of each respective device is read in series.

Assignees

• Univ Drexel
• Univ Pennsylvania

Inventors

• Spanier Jonathan E
• Gu Zongquan
• Islam Mohammad A
• Saldana-Greco Diomedes
• Rappe Andrew Marshall

Classifications

• G01N21/6489 Primary

  Photoluminescence of semiconductors · CPC title

• G01N21/76

  Chemiluminescence; Bioluminescence · CPC title

• G01N2021/7786

  Fluorescence · CPC title