DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of Application
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 04/06/2026 has been entered.
Receipt of Applicants’ Amended claims, Arguments and Remarks and filed on 04/06/2026 is acknowledged.
Claims 1, 3, 4, 10-14, 18, and 43-44 are pending.
Claims 2, 5-9, 15-17, 19-42 are cancelled.
Claim 24 remains withdrawn from further consideration pursuant to 37 CFR 1.14(b) as being drawn to a nonelected invention.
Claims 1, 3, 4, 10-14, 18, and 43-44 are amended.
Claims 45 and 46 are new.
Claims 1, 3, 4, 10-14, 18, and 43-46 are pending and under examination in this application.
Withdrawn Rejections
Claim Rejections - 35 USC § 112
The rejection of claims 1, 11, 35, 43, and 44 under 35 U.S.C. § 112(a) for failing to comply with the written description requirement, as set forth in the Office Action mailed January 14, 2026, is hereby withdrawn in view of Applicant’s amendments to claim 1. Amended claim 1 now recites chalcogenide nanoparticles comprising a chalcogen-based material that consists of Cu₂₋ₓSe, wherein the chalcogenide nanoparticles generate upconverted light through plasmon resonance in the chalcogen-based material. This amendment ties the functional language directly to the specific Cu₂₋ₓSe material composition disclosed and demonstrated in the specification, resolving the written description concern identified in the prior action.
Claim Rejections - 35 USC § 102
The rejection of claims 1, 2, 9, and 10 under 35 U.S.C. § 102(a)(1) and 102(a)(2) as anticipated by Klopfer et al. (US 9,267,889 B1), as set forth in the Office Action mailed January 14, 2026, is hereby withdrawn. Amended claim 1 now recites a solar cell comprising chalcogenide nanoparticles wherein the chalcogen-based material consists of Cu₂₋ₓSe, and wherein the chalcogenide nanoparticles generate upconverted light through plasmon resonance in the chalcogen-based material, with a light absorber configured to perform photovoltaic conversion. Klopfer does not specifically teach a composition consisting of Cu₂₋ₓSe, nor upconversion through plasmon resonance in the chalcogen-based material itself. The § 102 rejection is therefore not maintained.
Specification - Claim Objections
The specification is objected to as failing to provide proper antecedent basis for the claimed subject matter. See 37 CFR 1.75(d)(1) and MPEP § 608.01(o). Correction of the following is required:
Claims 1, 12, and 44, are objected to because the claims recite “chalcogen-based material”. Despite that Applicant has defined the term “chalcogen-based material” in the claims, this term does not appear in the originally-filed specification at all. Therefore, it lacks antecedent basis.
Appropriate correction is required.
New Rejections
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3, 4, 10-14, 18, and 43-46 are rejected under 35 U.S.C. 103 as being unpatentable over KR 101489913 B1 (hereinafter the reference is referred as
KR ‘913) in view of evidentiary reference Warkentin (Continuous Wave Upconversion from a Copper Selenide Nanocrystal Film), Dorfs et al. (Reversible Tunability of the Near-Infrared Valence Band Plasmon Resonance in Cu(2-x)Se Nanocrystals (hereinafter the reference is referred as Dorfs), and further in view of Balitskii et al. (Tuning the Localized Surface Plasmon Resonance in Cu2-xSe Nanocrystals by Postsynthetic Ligand Exchange (hereinafter the reference is referred as Balitskii); additionally by reference from previous office action filed in 1/14/2026, Spitzer (US 2012/0060918) for the embedded nanoparticles limitation; Sum (US 2018/0002354) for the perovskite absorber limitation; and Chen (US 2003/0030067) for meeting the limitation of claim 18 for chalcogenide nanoparticles are bound…into a patient undergoing medical treatment.
KR ‘913 teaches a gap plasmon resonator (GPR) comprising upconversion nanoparticles and a solar cell using the same, with the objective of improving the luminous efficiency of an upconversion nanomaterial by using plasmon characteristics, demonstrating superior luminescence even at low power density, and achieving superior photoelectric conversion efficiency when used as a solar cell (abstract). KR ‘913 discloses a solar cell comprising upconversion nanoparticles based on chalcogenide materials with diameters of 5 to 50 nm (¶ 0005), configured to absorb infrared light and convert it into visible light for absorption by a photoactive layer, thereby reducing energy loss and improving conversion efficiency (¶ 0072). KR ‘913 further discloses plasmon resonance characteristics (¶¶ 0041–0042) and that the upconversion materials can absorb two or more low-energy photons and emit one high-energy photon (¶ 0002). KR ‘913 also discloses that the upconversion nanoparticles are a mixture of doped chalcogenides (¶¶ 0005, 0047).
KR ‘913 does not specifically teach that the chalcogen-based material of the upconversion nanoparticles consists of Cu₂₋ₓSe, that upconversion proceeds through plasmon resonance in the Cu₂₋ₓSe chalcogen-based material itself, or the specific performance parameters of claims 44–46.
Warkentin teaches the development of earth-abundant, non-toxic materials that efficiently convert near-infrared light into visible light, and that copper selenide-based materials (Cu₂₋ₓSe) meet these criteria due to their unique plasmonic properties (abstract). Critically, Warkentin teaches continuous-wave photon upconversion from a silica xerogel film containing degenerately doped Cu₂₋ₓSe nanocrystals, with an onset flux of approximately 1.96 ± 0.29 kW/cm² and a quantum yield of at least 1% (abstract; ¶ Results and Discussion). Warkentin further teaches that a plasmon-driven thermal mechanism likely plays a role in this upconversion process (abstract; ¶ Conclusion), and that the excellent thermoelectric properties of copper selenide combined with plasmon-driven heating of Cu₂₋ₓSe nanocrystal aggregates generate thermally excited charges that contribute to upconverted photoluminescence (¶ Conclusion). Warkentin is applied as an evidentiary reference to demonstrate that Cu₂₋ₓSe nanocrystals are known in the art to generate upconverted light through plasmon resonance in the Cu₂₋ₓSe chalcogen-based material itself, at continuous-wave intensities compatible with solar applications.
Dorfs teaches that Cu₂₋ₓSe nanocrystals possess a tunable localized surface plasmon resonance (LSPR) in the near-infrared region arising from free carrier holes, and that the LSPR can be reversibly tuned by controlling the copper deficiency (carrier density) of the Cu₂₋ₓSe nanocrystals (abstract; entire article). Dorfs specifically teaches that Cu₂₋ₓSe nanocrystals exhibit LSPR peaks in the NIR due to free carriers arising from copper vacancies (i.e., hole-doping), directly establishing the structural and optical basis for plasmon resonance in Cu₂₋ₓSe as a composition consisting of that material.
Balitskii teaches Cu₂₋ₓSe nanocrystals with tunable Localized Surface Plasmon Resonance (LSPR) in the Near-Infrared Range (NIR) region, and that postsynthetic ligand exchange on the Cu₂₋ₓSe nanocrystal surface modifies the LSPR properties (abstract; entire article). Balitskii therefore teaches Cu₂₋ₓSe nanocrystals comprising ligands or small molecules bound to the chalcogen-based material.
Spitzer teaches an energy conversion device directed to a photovoltaic solar cell, wherein the device minimized losses due to non-absorption and thermalization in solar cells by up-converting the energies of incident photons prior to absorption by the semiconductor and improves the optical coupling between the semiconductor and an upconversion material (¶ 0006).
Sum teaches nanocrystal comprising a core comprised in a shell, wherein the core comprises a first material of a perovskite structure (abstract).
Chen teaches devices directed in general to upconversion luminescence (UCL) materials and methods of making and using same and more particularly, but not meant to be limiting, to Mn doped semiconductor nanoparticles for use as UCL materials. The present invention also relates in general to upconversion luminescence including two-photon absorption upconversion, and potential applications using UCL materials, including light emitting diodes, upconversion lasers, infrared detectors, chemical Sensors, temperature and pressure Sensors, ultraviolet and radiation detectors and biological labels, all of which incorporate a UCL material. (¶ 0017).
Regarding claims 1, 4 and 10, KR ‘913 teaches a solar cell comprising upconversion nanoparticles based on chalcogenide materials with plasmon resonance characteristics configured to convert infrared light into visible light for absorption by a photoactive layer performing photovoltaic conversion (¶¶ 0041–0042, 0066, 0072). KR ‘913 teaches the device used as a solar cell with improved photoelectric conversion efficiency (abstract; ¶ 0072), meeting the limitation that the device is part of a solar cell. Furthermore, KR ‘913 further teaches upconversion nanoparticle diameters of 5 to 50 nm (¶ 0005), which overlaps the claimed 10 to 30 nm range of claim 10, and that the solar cell incorporates a back reflection layer configured to absorb infrared rays and re-emit visible light into the photoactive layer (¶ 0072), consistent with the solid transparent embedding layer of claim 4. Warkentin teaches that Cu₂₋ₓSe nanocrystals are the chalcogen-based material generating upconverted light through plasmon resonance in the chalcogen-based material. Dorfs confirms that the chalcogen-based material of Cu₂₋ₓSe nanocrystals consists of Cu₂₋ₓSe and that LSPR arises intrinsically from the copper vacancy structure of that material.
It would have been obvious to a person having ordinary skill in the art (PHOSITA) before the effective filing date to substitute the Cu₂₋ₓSe nanocrystals of Warkentin and Dorfs for the upconversion nanoparticles of KR ‘913’s solar cell, because Warkentin establishes that Cu₂₋ₓSe nanocrystals perform photon upconversion via a plasmon-driven mechanism under continuous-wave illumination at intensities relevant to solar cell operation, and KR ‘913 explicitly teaches the objective of using plasmonic upconversion nanoparticles to improve solar cell efficiency. A PHOSITA would have had a reasonable expectation of success given that both KR ‘913 and Warkentin are directed to plasmon-enhanced upconversion in a solar cell context, and Warkentin directly demonstrates the operability of Cu₂₋ₓSe for this purpose. See MPEP 2141 (III)(A)–(G).
Regarding claim 3, Dorfs teaches that the free carrier holes responsible for LSPR in Cu₂₋ₓSe nanocrystals arise from copper vacancies, which constitute intrinsic hole-doping of the Cu₂₋ₓSe material (entire article). Therefore, the limitation that the Cu₂₋ₓSe is hole-doped is taught by Dorfs.
Regarding claims 11 and 43, KR ‘913 teaches upconversion materials that convert long-wave electromagnetic waves into shorter wavelengths, specifically absorbing infrared rays and re-emitting them as visible light (¶¶ 0002, 0064, 0041–0042). Warkentin teaches that the Cu₂₋ₓSe nanocrystal upconversion process is driven by plasmon resonance in the material, and that the spectral output of the upconverted emission is characteristic of the plasmon resonance mechanism in Cu₂₋ₓSe (abstract; ¶ Results and Discussion). It would therefore have been obvious to configure the upconversion nanoparticles to upconvert infrared light into visible light through plasmon resonance (claim 11), and to generate upconverted light with spectral characteristics matching those of the plasmon resonance (claim 43), given that Warkentin directly teaches this spectral relationship as inherent to the Cu₂₋ₓSe plasmon upconversion mechanism.
Regarding claim 12, Balitskii teaches Cu₂₋ₓSe nanocrystals comprising ligands bound to the surface of the chalcogen-based material for LSPR tuning purposes. Therefore, the limitation of claim 12 that the chalcogenide nanoparticles comprise ligands or small molecules bound to the chalcogen-based material is taught by Balitskii.
Regarding claims 13 and 14, KR ‘913 teaches an organic base absorber as the light-sensitive material (¶ 0070). The prior Final Office Action’s treatment of Spitzer (US 2012/0060918) for the embedded nanoparticles limitation and Sum (US 2018/0002354) for the perovskite absorber limitation is hereby incorporated by reference. Spitzer teaches that an upconversion composite material is disposed within cavities formed in the photon-absorbing semiconductor material (¶¶ 0007, 0031), meeting the limitation of claim 13 that the chalcogenide nanoparticles are embedded in the light absorber. Sum teaches a nanocrystal comprising a core of perovskite structure (¶¶ 0012–0014), meeting the limitation of claim 14 that the light absorber is a perovskite light absorber.
Regarding claim 18, Chen (US 2003/0030067) teaches that upconversion luminescence (UCL) nanoparticles can be conjugated to biological material and bound to coatings for use within a patient undergoing medical treatment (¶¶ 0158, 0165), meeting the limitation of claim 18 that the chalcogenide nanoparticles are bound to a coating suitable for placement into a patient undergoing medical treatment.
Regarding claim 44, Warkentin teaches Cu₂₋ₓSe nanocrystal upconversion with an onset flux of approximately 1.96 ± 0.29 kW/cm² for 1064 nm input light (abstract). The claimed upconversion threshold of less than 9 kW/cm² for 10⁵ nanoparticles in an interaction volume encompasses the range demonstrated by Warkentin, and it would have been obvious that this parameter is a result-effective variable subject to optimization through particle size, copper deficiency, and aggregation state as taught by Dorfs and Balitskii. See KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (2007).
Regarding claims 45 and 46, Warkentin teaches an internal quantum yield of at least 1% and an onset flux of approximately 1.96 kW/cm² (approximately 1960 W/cm²) for 1064 nm input light from Cu₂₋ₓSe nanocrystals. Dorfs and Balitskii teach that both the LSPR intensity and wavelength of Cu₂₋ₓSe nanocrystals are tunable through copper deficiency and ligand exchange, respectively, which are known to affect upconversion efficiency and threshold. It would have been obvious to a PHOSITA to optimize the copper vacancy density and surface chemistry of the Cu₂₋ₓSe nanocrystals, as taught by Dorfs and Balitskii, to achieve improved quantum yield and lower onset power density, since these parameters are identified as result-effective variables in the art and routine optimization thereof would be expected to yield incremental improvements. Specifically, the claimed internal quantum yield of at least 2% (claim 45) represents approximately a two-fold improvement over Warkentin’s reported lower limit, and the claimed onset power density of less than 1000 W/cm² (claim 46) represents a reduction from Warkentin’s approximately 1960 W/cm² — both values within the range that routine optimization of copper deficiency and ligand environment, as taught by Dorfs and Balitskii, would predictably achieve. See In re Aller, 220 F.2d 454 (CCPA 1955); KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (2007).
Response to Arguments
Applicant Remarks and Arguments filed 04/06/2026 have been fully considered. The § 112(a) and § 102 rejections have been withdrawn as indicated above. Applicant’s arguments regarding the § 103 rejection are addressed as follows.
Argument 1 KR ‘913 / Plasmon Resonance Argument:
Applicant argues that KR ‘913’s upconversion nanoparticles are doped with ytterbium (Yb) or erbium (Er) and that the upconversion mechanism relies on non-plasmonic dopant-based processes, not plasmon resonance in a Cu₂₋ₓSe chalcogen-based material. The Examiner acknowledges this distinction and has restructured the rejection accordingly. The present rejection does not rely on KR ‘913 to teach plasmon resonance in Cu₂₋ₓSe or the “consists of Cu₂₋ₓSe” limitation. Rather, KR ‘913 is relied upon solely for the solar cell architecture — specifically, the use of upconversion nanoparticles in a back-reflection layer of a solar cell to convert infrared light to visible light for absorption by a photoactive layer performing photovoltaic conversion. The plasmon resonance in Cu₂₋ₓSe and the “consists of Cu₂₋ₓSe” limitations are supplied by Warkentin and Dorfs, both of which are of record in the IDS and directly teach Cu₂₋ₓSe nanocrystals with intrinsic LSPR-driven upconversion. The motivation to combine is that a PHOSITA seeking to improve the solar cell architecture of KR ‘913 would have turned to Warkentin’s demonstration that Cu₂₋ₓSe nanocrystals perform plasmon-driven continuous-wave upconversion at solar-relevant power densities, and would have substituted these nanoparticles into KR ‘913’s device framework with a reasonable expectation of success.
Argument 2, Regarding claim 43 specifically:
Applicant argues that KR ‘913 does not disclose chalcogenide nanoparticles configured to generate upconverted light with spectral characteristics matching spectral characteristics of the plasmon resonance, and that “tuning the optical response to overlap with the plasmon resonance frequency” is not the same limitation. The Examiner agrees that KR ‘913 alone does not establish this limitation. However, Warkentin teaches that the spectral characteristics of the upconverted emission from Cu₂₋ₓSe nanocrystals are directly linked to and characteristic of the plasmon resonance mechanism in that material (abstract; ¶ Results and Discussion). Because Warkentin establishes that the Cu₂₋ₓSe plasmon resonance inherently produces upconverted emission whose spectral characteristics match the plasmon resonance, this limitation is met when the Cu₂₋ₓSe nanocrystals of Warkentin are incorporated into the solar cell of KR ‘913.
Argument 3, Regarding claim 44 specifically:
Applicant argues that Warkentin’s nanocrystals have not been demonstrated to have the same structure as those of other references, and therefore cannot be applied as an evidentiary reference to the nanoparticles of KR ‘913. The Examiner notes that Warkentin is applied as an evidentiary reference to characterize the properties of Cu₂₋ₓSe nanocrystals as a material class, and Dorfs and Balitskii independently confirm the LSPR and upconversion properties of Cu₂₋ₓSe nanocrystals. The upconversion threshold claimed in claim 44 (less than 9 kW/cm²) encompasses the value reported by Warkentin (approximately 1.96 kW/cm²), and a PHOSITA would have understood that Cu₂₋ₓSe nanocrystals as a class exhibit this property given the established relationship between copper vacancy density and LSPR properties taught by Dorfs.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDRE MACH whose telephone number is (571)272-2755. The examiner can normally be reached 0800 - 1700 M-F.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Robert A Wax can be reached at 571-272-0323. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/ANDRE MACH/Examiner, Art Unit 1615
/Jeffrey T. Palenik/Primary Examiner, Art Unit 1615
Prosecution Insights