DETAILED ACTION
This is the third Office Action regarding application number 18/039,820, filed on 06/01/2023, which is a 371 of PCT/US2021/061464, filed on 12/01/2021, and which claims priority to provisional application number 63/120,555, filed on 12/02/2020.
This action is in response to the Applicant’s Response received 06/27/2025.
Status of Claims
Claims 1-10, 13, 16, 21, 22, 28-30, and 45-47 are currently pending.
Claims 11, 12, 14, 15, 17-20, 23-27, and 31-44 are cancelled.
Claim 46 is amended.
Claims 8-10 and 16 are withdrawn.
Claims 1-7, 21, 22, 28-30, and 45-47 are examined below.
The rejection of claims 46 and 47 under 35 U.S.C. § 112 has been withdrawn in light of the Applicant’s amendments.
No claim is allowed.
Response to Arguments
The Applicant’s arguments received 06/02/2025 have been carefully considered but they are not found persuasive.
The applicant argues that MIANDAL does not suggest any interaction with or relationship to compositional elements of an adjacent layer (Remarks 7). The examiner has considered the applicant’s remarks but does not find them compelling at this time. Specifically, the examiner relies on the primary BLAYDES references to teach the claimed layer arrangements. MIANDAL is relied upon strictly for its teachings of forming a Cd-rich surface at the interface thus forming the Cd-rich surface directly adjacent to the final position of the p-type contact layer.
The examiner requests further explanation of the applicant’s position.
Claim Rejections - 35 USC § 103
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
Claims 1-4, 6, 7, 21, 28, 30, and 45 are rejected under 35 U.S.C. 103 as being unpatentable over BLAYDES (US 2014/0326315 A1) in view of REESE (“Intrinsic surface passivation of CdTe”) and MIANDAL (“The Structural and Optical Properties of Poly (Triarylamine) (PTAA) Thin Films Prepared at Different Spin Rate Using Spin Coating Method”).
Regarding claim 1, BLAYDES teaches a method of making a photovoltaic device comprising:
forming an absorber layer (absorber layer 120) over a substrate stack (layer stack 110), wherein the absorber layer comprises a type II-VI semiconductor material, wherein the type II material includes cadmium (Cd) and the type VI material includes tellurium (Te) (para. 59 describes the claimed materials);
depositing a p-type contact layer (p-type layer 130) over the absorber layer, whereby the p-type contact layer is directly adjacent to the Cd surface (p-type contact layer 130 directly contacts layer Cd absorber layer 120); and
depositing a conductive layer (contact layer 140, para. 66) over the p-type contact layer.
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BLAYDES does not disclose the step of contacting an alkaline wash fluid, comprising a hydroxide, to a second surface of the absorber layer to produce a Cd-rich surface, wherein a ratio of Cd to Te is greater than 1:1 and equal to or less than 4:1, or that and wherein the p-type contact layer comprises at least one of: PTAA, P3HT, poly-TPD,TFB, TTF-1, TF8-TAA, TIF8-TAA, SGT-407, PCDTBT, Spiro-OMeTAD, anthracene-based HTM, polythiophene, or semiconducting polymers.
REESE describes contacting an alkaline wash fluid, comprising a hydroxide, to a second surface of a CdTe absorber layer to produce a Cd-rich surface, wherein a ratio of Cd to Te is greater than 1:1. Specifically, REESE describes that KOH or NaOH generates a Cd:Te ratio of 1.12 and 1.35, respectively. The examiner asserts that these values are within the range claimed. REESE comments that the formation of a Cd-rich surfaces shows a significant reduction in surface recombination (abstract).
MIANDAL teaches PTAA semiconductor layers deposited by spin coating on a substrate at ambient conditions (pg. 1, left col.). MIANDIAL teaches that the use of PTAA is advantageous because of these low-temperature production steps.
Skilled artisans would have found it obvious to modify BLAYDES and add a method step that includes contacting an alkaline wash fluid, comprising a hydroxide, to a second surface of a CdTe absorber layer to produce a Cd-rich surface, wherein a ratio of Cd to Te is greater than 1:1 in order to significantly reduce surface recombination as taught by REESE.
Skilled artisans would have found it obvious to modify BLAYDES and replace the p-type semiconducting layer with PTAA because it would have advantages such as permitting low-temperature production steps, particularly allowing for deposition as ambient conditions (such as 25 degrees Celsius ambient temperature) as taught by MIANDAL.
Regarding claim 2, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the step of depositing the p-type contact layer is performed at a substrate temperature at or below 150 °C (MIANDAL teaches ambient temperature deposition, and this means naturally that the substrate temperature is around 25 degrees Celsius).
Regarding claim 3, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the hydroxide comprises at least one of: sodium hydroxide (NaOH), potassium hydroxide (KOH), or tetramethylammonium hydroxide ((CH3)4N(OH)) TMAH (REESE describes that both NaOH and KOH provide advantages to forming a Cd-rich surface).
Regarding claim 4, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the p-type contact layer comprises PIF8- TAA, poly-TPD, or PTAA undoped or doped with F4-TCNQ (MIANDAL teaches undoped PTAA).
Regarding claim 6, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the Cd-rich surface has a ratio of Cd to Te greater than 1:1 and equal to or less than 4:1 (REESE describes that KOH or NaOH generates a Cd:Te ratio of 1.12 and 1.35, respectively).
Regarding claim 7, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the p-type contact layer is deposited by slot- die coating, blade coating, roll coating, spray coating, spin coating (MIANDAL teaches spin coating process for depositing PTAA layer), evaporation, or sol-gel formation.
Regarding claim 21, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the p-type contact layer is heated at a temperature in a range of 80-150 °C prior to the step of depositing a conductive layer (MIANDAL states that “PTAA was then annealed at 130 C for 1 hour to eliminate any trapped solvent”).
Regarding claim 28, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the absorber layer comprises cadmium telluride selenide (absorber layer 120 includes cadmium, tellurium, and selenium, BLAYDES, para. 60).
Regarding claim 30, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the conductive layer is adjacent to the p-type contact layer, and the conductive layer comprises at least one metal or metal nitride (see BLAYDES, Fig. 5, illustrating the claimed layer arrangement).
Regarding claim 45, modified BLAYDES teaches or would have suggested the method of claim 1, wherein the p-type contact layer comprises at least one of: PTAA, P3HT, or SpiroOMeTAD (MIANDAL teaches PTAA).
Regarding claim 46, BLAYDES teaches a method of making a photovoltaic device comprising:
providing an absorber layer on a substrate stack (absorber layer 12),
wherein the absorber layer comprises a polycrystalline film; and the absorber layer has a second surface comprising a p-type alloy of cadmium (Cd) and tellurium (Te) (CdTe is a known polycrystalline p-type semiconductor);
forming an ohmic contact by depositing a p-type contact layer over the absorber layer (p-type layer 130);
the p-type contact layer is directly adjacent to the absorber layer; and
depositing a conductive layer (contact layer 140, para. 66) over the p-type contact layer,
wherein the conductive layer comprises at least one metal or metal nitride (para. 66, listing metals).
BLAYDES does not disclose expressly that there is an alkaline wash fluid contacting set for form a Cd-rich surface wherein the Cd-rich surface has a ratio of Cd to Te greater than 1.3:1 and equal to or less than 2.5:1, the p-type contact layer comprises an organic hole-transport material, or that forming an ohmic contact and depositing a conductive layer are performed at substrate stack temperatures below 150 °C.
REESE describes contacting an alkaline wash fluid, comprising a hydroxide, to a second surface of a CdTe absorber layer to produce a Cd-rich surface, wherein a ratio of Cd to Te is greater than 1:1. Specifically, REESE describes that KOH or NaOH generates a Cd:Te ratio of 1.12 and 1.35, respectively. The examiner asserts that these values are within the range claimed. REESE comments that the formation of a Cd-rich surfaces shows a significant reduction in surface recombination (abstract).
MIANDAL teaches an organic hole-transport material PTAA semiconductor layer deposited by spin coating on a substrate at ambient conditions (pg. 1, left col.). MIANDIAL teaches that the use of PTAA is advantageous because of these low-temperature production steps.
Skilled artisans would have found it obvious to modify BLAYDES and add a method step that includes contacting an alkaline wash fluid, comprising a hydroxide, to a second surface of a CdTe absorber layer to produce a Cd-rich surface, wherein a ratio of Cd to Te is 1.35, in order to significantly reduce surface recombination as taught by REESE.
Skilled artisans would have found it obvious to modify BLAYDES and replace the p-type semiconducting layer with PTAA because it would have advantages such as permitting low-temperature production steps (below 150C), particularly allowing for deposition as ambient conditions (such as 25 degrees Celsius ambient temperature) as taught by MIANDAL.
Claims 5 and 47 are rejected under 35 U.S.C. 103 as being unpatentable over BLAYDES (US 2014/0326315 A1) in view of REESE (“Intrinsic surface passivation of CdTe”) and MIANDAL (“The Structural and Optical Properties of Poly (Triarylamine) (PTAA) Thin Films Prepared at Different Spin Rate Using Spin Coating Method”) as applied to claim 1 above, and further in view of COLEGROVE (US 2021/0210606 A1).
Regarding claim 5, modified BLAYDES teaches or would have suggested the method of claim 1, but does not disclose expressly that the absorber layer is doped with at least one dopant selected from phosphorus, arsenic, antimony, or bismuth.
COLEGROVE teaches that the incorporation of antimony and arsenic (group V elements) into II-VI semiconductor materials such as CdTe-based cells enables higher carrier concentrations (more built-in charge), will not compromise lifetime, and may be significantly more stable (para. 4).
Skilled artisans would have found it obvious to dope the CdTe-based absorber layer with antimony, arsenic, or other group V elements because these enable higher carrier concentrations (more built-in charge), will not compromise lifetime, and may be significantly more stable as taught by COLEGROVE.
Regarding claim 47, modified BLAYDES teaches or would have suggested the method of claim 46, wherein: the contacting step comprises contacting the alkaline wash fluid to the p-type alloy of cadmium and tellurium for a contact time in a range of 10 seconds to 30 minutes (REESE describes 15s and 300s etches, pg. 155305-3); and the alkaline wash fluid comprises potassium hydroxide at a concentration in a range from 0.500 M to 4.000 M (the “Transene PSE200 solution" used by REESE is known to have a molarity between 2-3M, as this is about the molarity of 1:7 KOH:H2O solution); and the organic hole-transport material comprises at least one of: PTAA or P3HT (MIANDAL teaches PTAA).
Modified BLAYDES does not disclose that the p-type alloy of cadmium and tellurium is doped with arsenic (As);
COLEGROVE teaches that the incorporation of antimony and arsenic (group V elements) into II-VI semiconductor materials such as CdTe-based cells enables higher carrier concentrations (more built-in charge), will not compromise lifetime, and may be significantly more stable (para. 4).
Skilled artisans would have found it obvious to dope the CdTe-based absorber layer with antimony, arsenic, or other group V elements because these enable higher carrier concentrations (more built-in charge), will not compromise lifetime, and may be significantly more stable as taught by COLEGROVE.
Claims 22 and 29 are rejected under 35 U.S.C. 103 as being unpatentable over BLAYDES (US 2014/0326315 A1) in view of REESE (“Intrinsic surface passivation of CdTe”) and MIANDAL (“The Structural and Optical Properties of Poly (Triarylamine) (PTAA) Thin Films Prepared at Different Spin Rate Using Spin Coating Method”) as applied to claim 1 above, and further in view of QIN (CN 110556433 A).
Regarding claims 22 and 29, the combination of BLAYDES and REESE teaches or would have suggested the method of claim 1, but does not disclose expressly that heat treatment of the p-type contact layer is performed using a hot plate, an oven, and or a pressure-controlled heating chamber (claim 22), or wherein the p-type contact layer has a thickness in a range between 0.5 nm and 100 nm (claim 29).
QIN teaches a method of preparing a CdTe solar cell that includes a PTAA film interface charge transport layer with a thickness of 12 nm (para. 16). QIN states that heat treatment is performed on a heating table (para. 55), which the examiner interprets to mean a hot plate. Methods and devices of heat treatment are well-known in the art, and hot plates and heating tables are known as suitable equivalents.
Skilled artisans would have found it obvious to further modify BLAYDES and provide a PTAA contact layer (that would be p-type) according to the recited thicknesses and heating apparatuses in order to produce a device having reduced carrier recombination and improved device performance as taught by QIN (paras. 65 and 73).
Conclusion
No claim is allowed.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANGELO TRIVISONNO whose telephone number is (571) 272-5201 or by email at <angelo.trivisonno@uspto.gov>. The examiner can normally be reached on MONDAY-FRIDAY, 9:00a-5:00pm EST.
If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, ALLISON BOURKE, can be reached at (303) 297-4684.
/ANGELO TRIVISONNO/
Primary Examiner, Art Unit 1721