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 .
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim 1 and 5-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over a publication to Khoram, et al. entitled “Growth and characterization of PDMS-stamped halide perovskite single microcrystals,” Journal of Physical Chemistry, Vol. 120, pp. 6475-81 (2018) (hereinafter “Khoram”) in view of a publication to Chen, et al. entitled “General space-confined on-substrate fabrication of thickness-adjustable hybrid perovskite single-crystalline thin films,” Journal of the American Chemical Society, Vol. 138, pp. 16196-99 (2016) (“Chen”).
Regarding claim 1, Khoram teaches a method of preparing a single crystal perovskite (see the Abstract, Figs. 1-3, and entire reference which teach a method of preparing single crystals of a perovskite), comprising:
applying a perovskite precursor solution onto a substrate (see Fig. 1 and the Experimental Methods section at p. 6476 which teach preparing a halide perovskite solution by mixing PBr2 with CH3NH3Br in dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) and spin-coating the solution onto a fused silica substrate);
covering the perovskite precursor solution with a polymer cover (see Fig. 1 and the Experimental Methods section at p. 6476 which teach that the wet substrate was pressed face down onto a piece of PDMS); and
heat treating the perovskite precursor solution to grow the single crystal perovskite (see Fig. 1 and the Experimental Methods section at p. 6476 which teach heating on a hot plate at 100 °C or 150 °C for 2-5 min until single crystals of CH3NH3PbBr3 formed),
wherein a shape and a size of the grown single crystal vary depending on a type of the substrate (see Fig. 1, the Experimental Methods section at p. 6476, and the Results and Discussion section at pp. 6476-77 which teach that since the precursor is spin-coated on the substrate, the size and type of substrate necessarily causes the shape and size of the grown single crystals to vary due to, for example, limitations in the available real estate based on the size and shape of the substrate as well as van der Waals, chemical, electrical, and/or other forces occurring between the film and substrate).
Khoram does not teach that the substrate is a flexible substrate which includes at least one selected from the group consisting of polyimide (PI), polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyvinylidene-chloride (PVDC). However, in Figs. 1-2 and pp. 16196-97 Chen teaches an analogous method of fabricating perovskite crystals by solution growth in which a precursor solution provided between two substrates is heated to induce the crystallization of a perovskite within the solution. In the first full paragraph on p. 16197 Chen specifically teaches that growth of the perovskite single crystal film did not require lattice matching with the substrate and could be grown on a variety of flat surfaces including flexible plastic substrates such as polyethylene terephthalate (PET). Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Chen and would recognize that a flexible material such as PET may be used as the substrate in the method of Khoram with the motivation for doing so being to produce flexible electronic devices. The combination of prior art elements according to known methods to yield predictable results has been held to support a prima facie determination of obviousness. All the claimed elements are known in the prior art and one skilled in the art could combine the elements as claimed by known methods with no change in their respective functions, with the combination yielding nothing more than predictable results to one of ordinary skill in the art. KSR International Co. v. Teleflex Inc., 550 U.S. 398, __, 82 USPQ2d 1385, 1395 (2007). See also, MPEP 2143(A).
Regarding claim 5, Khoram teaches that the polymer cover includes at least one selected from the group consisting of polyimide (PI), polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyvinylidene-chloride (PVDC) (see Fig. 1 and the Experimental Methods section at p. 6476 which teach that the wet substrate was pressed face down onto a piece of PDMS which functions as the polymer cover).
Regarding claim 6, Khorma teaches applying a pressure to the polymer cover before the heat treating (see Fig. 1 and the Experimental Methods section at p. 6476 which teach that the wet substrate was pressed face down onto a piece of PDMS which necessarily applies pressure to the PDMS; moreover, the application of pressure necessarily occurs before the perovskite solution is heated to the growth temperature of 100 or 150 °C).
Regarding claim 7, Khoram teaches that the heat treating is performed in a temperature range of 60°C to 100°C (see Fig. 1 and the Experimental Methods section at p. 6476 which teach heating on a hot plate at 100 °C for 2-5 min until single crystals of CH3NH3PbBr3 formed).
Regarding claim 8, Khoram teaches that the heat treating is performed in a pressure range of 0.5 bar to 1 bar (See Fig. 1 and the Experimental Methods section at p. 6476 which teach heating on a hot plate at 100 °C for 2-5 min until single crystals of CH3NH3PbBr3 formed. A person of ordinary skill in the art prior to the effective filing date of the invention would recognize that this was performed at atmospheric pressure or 760 Torr which is sufficiently close to the claimed upper limit of 1 bar (750 Torr) that it would be reasonably expected to yield the same result. A prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have the same properties. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985). See also MPEP 2144.05(I). Alternatively, since the pressure during crystal growth influences crystal formation, including the solvent evaporation rate, it is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). It therefore would have been within the capabilities of a person of ordinary skill in the art to utilize routine experimentation to determine the optimal pressure, including within the claimed range of 0.5 to 1 bar, necessary to produce perovskite single crystals in the method of Khoram and Chen which possess the desired materials properties.
Claims 3-4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Khoram in view of Chen and further in view of U.S. Patent Appl. Publ. No. 2021/0062364 to Joglekar, et al. (“Joglekar”).
Regarding claim 3, Khoram and Chen do not teach that the flexible substrate includes a spacer formed on the flexible substrate. However, in Figs. 2-3 and ¶¶[0113]-[0127] as well as elsewhere throughout the entire reference Joglekar teaches an analogous system and method for the growth of perovskite single crystal from a solution. In Figs. 2A & 3A-C and ¶¶[0117]-[0119] Joglekar specifically teaches the use of a spacer formed from sidewalls comprised of a polymeric material such as polydimethylsiloxane (PDMS) to contain the precursor solution within a predefined area with a defined thickness. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Joglekar and would be motivated to incorporate one or more spacers manufactured from a polymeric material such as PDMS in the method of Khoram and Chen in order to precisely define the area and thickness where crystallization of the perovskite solution occurs.
Regarding claim 4, Khoram and Chen do not teach that the spacer includes at least one selected from the group consisting of polyimide (PI), polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyvinylidene-chloride (PVDC). However, as noted supra with respect to the rejection of claim 3, in Figs. 2A & 3A-C and ¶¶[0117]-[0119] Joglekar specifically teaches the use of a spacer formed from sidewalls comprised of a polymeric material such as polydimethylsiloxane (PDMS) to contain the precursor solution within a predefined area with a defined thickness. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Joglekar and would be motivated to incorporate one or more spacers manufactured from a polymeric material such as PDMS in the method of Khoram and Chen in order to precisely define the area and thickness where crystallization of the perovskite solution occurs.
Response to Arguments
Applicants’ arguments filed January 22, 2026, have been fully considered but they are not persuasive.
Applicants argue that Khoram does not teach or suggest that the shape and size of the grown crystal varies depending on a type of flexible substrate as recited in amended claim 1. See applicants’ 1/22/2026 reply, pp. 6-10. Applicants’ argument is noted, but is unpersuasive. First, it is Chen rather than Khoram that is relied upon to teach the use of a flexible substrate. Although Khoram teaches a method which utilizes silica substrates, it is the Examiner’s position that the use of different sizes and types of substrates will necessarily cause the shape and size of the grown crystals to vary. This necessarily is the case since if the substrate is smaller than the crystal size then the thus-produced crystal cannot be any larger than the substrate supporting it which therefore means that the shape and size of the grown single crystal varies depending on the shape and size of the substrate used. Moreover, since the resulting crystals are influenced by variables such as van der Waals, chemical, and electrical forces arising from the nature of the substrate used (i.e., whether it is a ceramic, glass, metal, or a type of polymer), it is the Examiner’s position that the shape and size of the grown single crystal will necessarily vary depending on the materials properties of the substrate that is used.
Applicants then argue that since Chen relates to the general space-confined on-substrate fabrication of thickness-adjustable hybrid perovskite single crystal films, Chen does not teach or suggest that the shape and size of the grown single crystal varies depending on the type of flexible substrate and that the use of different flexible substrates unexpectedly produces crystals of different sizes and shapes. Id. at pp. 10-12. Applicants’ argument is noted, but is unpersuasive. Although the exact procedure utilized in Chen has some differences from Khoram, both processes involve spreading a perovskite solution across the surface of a substrate and then controlling the temperature in order to induce crystallization. As such, the teachings of both Chen and Khoram are considered both analogous art and reasonably pertinent to the problem to be solved, which is that of crystallization of perovskite thin films onto a substrate from a solution. Since the first full paragraph on p. 16197 of Chen teach that growth of a perovskite single crystal film does not require lattice matching and may occur on flexible plastic substrates such as PET, a person of ordinary skill in the art would be motivated to utilize a flexible plastic substrate such as PET in place of the silica glass utilized in the method of Khoram in order to, for example, produce flexible electronic devices. Moreover, for the same reasons as noted supra, the use of different shapes, sizes, and types of flexible plastic substrates will necessarily cause the shape and size of the grown single crystal to depend on the shape, size, and type of flexible plastic substrate that is used.
Applicants then argue that Joglekar does not remedy the above-noted deficiencies in claim 1. Id. at pp. 12-14. Applicants’ argument is noted, but is moot as it is the Examiner’s position that the limitations recited in claim 1 are fully taught by the combination of Khoram and Chen. In this case Joglekar is merely introduced to teach the limitations relating to the use of a spacer as recited in dependent claims 3 and 4.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714