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(s) 1-2, 5-7, 10, 14-15, 17-18, 20, 23, and 26-28 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Appl. Publ. No. 2023/0242812 to Grenet, et al. (hereinafter “Grenet”) in view of U.S. Patent Appl. Publ. No. 2018/0277365 to Burst, et al. (“Burst”) and further in view of a publication to Murata, et al. entitled “Effect of high-temperature post-deposition annealing on cesium lead bromide thin films deposited by vacuum evaporation,” AIP Advances, Vol. 10, p. 045031 (2020) (“Murata”) and still further in view of a publication to Rakita, et al. entitled “Low-temperature solution-grown CsPbBr3 single crystals and their characterization,” Crystal Growth & Design, Vol. 16, pp. 5717-25 (2016) (“Rakita”).
Regarding claim 1, Grenet teaches a method for depositing a film on a substrate (see, e.g., the Abstract, Figs. 1-7, and entire reference), the method comprising:
preparing a source material, the source material comprising single crystals (see Fig. 6 and ¶¶[0173]-[0218] which teach the use of a target (20) comprised of single crystals of CsPbBr3 as a source material which has been prepared by a process which includes, inter alia, grinding and pressing a powder);
providing the source material on a first heater (see, e.g., Figs. 4-5 and ¶¶[0142]-[0152] which teach providing the source material (20) on a heater in the form of susceptor (106)),
providing the substrate on a second heater (see, e.g., Figs. 4-5 and ¶¶[0142]-[0152] which teach that the substrate is provided on a cover (108) which is in the form of a susceptor and, hence, is considered a heater),
the substrate being disposed a first distance from the source material, the first distance being less than 10 millimeters (mm) (see, e.g., Figs. 4-5 and ¶[0150] which teach that the substrate (10) is 0.5 to 5 mm from the target (20));
performing a close space sublimation (CSS) process to deposit the film of the source material on the substrate by simultaneously heating the source material with the first heater to a first temperature and heating the substrate with the second heater to a second temperature (see, e.g., Figs. 4-5 and ¶¶[0154]-[0169] which teach that CSS is used to deposit a film (1) comprised of source material from the target (20) by heating the target (20) to a first temperature and hearing the substrate (10) to a second temperature);
after performing the CSS process, allowing the substrate to cool to room temperature (see, e.g., ¶[0170] which teaches that the substrate is allowed to cool after deposition is complete; moreover, the sample is necessarily cooled to room temperature in order to facilitate safe handling),
wherein the film has the same stoichiometry as the source material (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)), and
wherein the film has a thickness in a range of from 100 nanometers (nm) to 100 micrometers (um) (see, e.g., ¶[0076] and ¶[0215] which teach that the thickness may be from 100 nanometers to 100 micrometers).
Grenet does not teach that the first temperature, second temperature, and a time of the CSS process are controlled such that a grain size of the film is the same as a thickness of the film. However, in ¶[0154] Grenet teaches that the temperature of the substrate (10) and target (20) as well as the temperature gradient therebetween can be adjusted to control the morphology of the deposited thin film (1), including the size of the crystal grains formed thereupon while ¶[0166] of Grenet further teaches that grain growth occurs via the process of germination, nucleation, and then growth which necessarily is time-dependent which means that one of the variables controlling the grain size is the duration of film growth. Then in Figs. 1-7 and ¶¶[0018]-[0028] Burst teaches an analogous method of producing large-grained polycrystalline Group II-VI semiconductors such as CdTe by CSS. This is achieved by, for example, controlling the temperature of the source material and the substrate, the growth ambient, and the duration of growth such that a single crystal or large-grained polycrystalline material is deposited. This is specifically disclosed in ¶[0018] which teaches that the average grain size may be greater than twice a thickness of the layer as well as Fig. 7 and ¶[0028] which teach an embodiment where a large-grained polycrystalline CdTe layer in which the grain size is the same as the film thickness is obtained by adjusting the CSS growth conditions. It therefore would have been within the capabilities of a person of ordinary skill in the art prior to the effective filing date of the invention to utilize routine experimentation to determine the optimal temperatures for the substrate (10) and target (20) as well as the growth duration necessary to produce a grain size in the film that is the same as a thickness of the film with the motivation for doing so being to produce a thin film having the desired materials properties for a particular application.
Grenet and Burst do not teach after allowing the substrate to cool to room temperature, performing a post-deposition annealing on the film by heating it to a third temperature for a predetermined period of time, wherein the third temperature is at least 450 °C and the predetermined period of time is at least 1 hour. However, in Figs. 1-5 and the Results and Discussion section at pp. 045031-2 to 045031-5, Murata teaches that by performing a post-deposit anneal (PDA) at temperatures of up to 500 °C for 60 min or more, the materials properties of a deposited CsPbBr3 are improved. This results in, for example, a larger grain size, an increase in the carrier diffusion length, and improved conversion efficiencies in solar cells. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Murata and would be motivated to perform a post-deposition anneal on the perovskite produced in the method of Grenet at a temperature of at least 450 °C for at least 1 hour in order to improve the materials properties of the deposited thin film for the production of higher quality electronic devices therefrom.
Grenet, Burst, and Murata do not teach that the source material is prepared using an antisolvent vapor crystallization process. However, in the Abstract, Fig. 1, and the section on Protocol for Crystal Growth at pp. 5718-20 Rakita teaches a low-temperature method of growing high-quality CsPbBr3 single crystals by an antisolvent vapor crystallization process from CsBr and PbBr2 powders that were initially dissolved in a solution of DMSO under ambient air at a temperature of 50 °C. This solution was then titrated with MeOH or MeCN and then filtered. The filtered precursor solution is then crystallized into CsPbBr3 using MeOH or MeCN as an antisolvent. X-ray diffraction (Fig. 2), SHG spectroscopy (Fig. 3), EDS, and thermal analysis (Fig. 4) results show that the solution-grown CsPbBr3 crystals are single crystals and exhibit properties similar to melt-grown and spin-coated CsPbBr3 crystals. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Rakita and would recognize that the CsPbBr3 single crystals utilized in the method of Grenet, Burst, and Murata may be produced by an antisolvent vapor crystallization process with the motivation for doing so being to utilize a lower cost and readily available method to quickly produce high quality CsPbBr3 single crystals as the source material. 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 2, Grenet teaches that the first distance is no more than 3 mm (see, e.g., Figs. 4-5 and ¶[0150] which teach that the substrate (10) is 0.5 to 5 mm from the target (20) and in a preferred embodiment may be 2 mm).
Regarding claim 5, Grenet teaches that the source material is a perovskite material and the film is a perovskite film (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Regarding claim 6, Grenet teaches that the source material is CsPbBr3 and the film is a CsPbBr3 film (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Regarding claim 7, Grenet teaches that the film has a thickness in a range of from 1 mm to 50 mm (see, e.g., ¶[0076] and ¶[0215] which teach that the thickness may be from 100 nanometers to 100 micrometers which encompasses the entirety of the claimed range).
Regarding claim 10, Grenet teaches that the source material comprises a powder of the single crystals ground up (see, e.g., Fig. 6 and ¶¶[0173]-[0218] which teach that the target (20) may be comprised of single crystals of CsPbBr3 obtained by grinding the source materials).
Regarding claim 14, Grenet teaches that the substrate is glass (see, e.g., ¶[0116] which teaches that the substrate (10) may be glass).
Regarding claim 15, Grenet teaches that the substrate is in direct physical contact with the second heater (see, e.g., Figs. 4-5 and ¶¶[0142]-[0152] which teach that the substrate (10) is in direct physical contact with the cover (108) which functions as a susceptor (i.e., a heater) that is heated by the heater (104)).
Regarding claim 17, Grenet teaches that the first temperature is higher than the second temperature (see, e.g., Figs. 4-5 and ¶¶[0159]-[0164] which teach that the temperature of the substrate (10) is lower than the temperature of the target (20)).
Regarding claim 18, Grenet teaches that the first temperature is at least twice the second temperature (see, e.g., Figs. 4-5 and ¶¶[0159]-[0164] which teach that the target (20) temperature may be up to 500 °C while the substrate (10) temperature is 250 °C).
Regarding claim 20, Grenet teaches that the first temperature and the second temperature are controlled by a first thermocouple and a second thermocouple, respectively (see, e.g., Figs. 4-5 and ¶¶[0153]-[0154] which teach that the temperature of the susceptor (106) and cover (108) is controlled by separate thermocouples (114)).
Regarding claim 23, Grenet teaches that the film has the same composition as the source material (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Regarding claim 26, Grenet teaches a film deposited by the method according to claim 1 (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Regarding claim 27, Grenet teaches that the film is a perovskite film (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Regarding claim 28, Grenet teaches that the film is a CsPbBr3 film (see, e.g., Figs. 6-7 and ¶¶[0199]-[0218] which teach that a CsPbBr3 film (1) is deposited using CsPbBr3 as the source material (20)).
Claims 11 and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Grenet in view of Burst and further in view of Murata and still further in view of U.S. Patent Appl. Publ. No. 2017/0268128 to Qi, et al. (“Qi”).
Regarding claim 11, Grenet teaches that the source material is provided on the first heater in a container (see, e.g., Figs. 4-5 and ¶¶[0142]-[0152] which teach that the target (20) is provided on the susceptor (106) which is shaped like a container). Alternatively, in Figs. 2-5 and ¶¶[0033]-[0050] Qi teaches an analogous system and method for depositing perovskite thin films by a vapor deposition technique. In ¶[0034] Qi specifically teaches that the evaporation unit (212) may be in the form of a crucible which is capable of holding a source material in the form of a powder. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Qi and would be motivated to place the powdered source material in a crucible placed on the susceptor (106) during sublimation growth according to the method of Grenet in order to provide a means for containing the powdered source material such that it can be readily inserted and removed from the deposition system.
Regarding claim 13, Grenet, Burst, and Murata do not teach that the container is in direct physical contact with the first heater. However, in Figs. 2-5 and ¶¶[0033]-[0050] Qi teaches an analogous system and method for depositing perovskite thin films by a vapor deposition technique. In ¶[0034] Qi specifically teaches that the evaporation unit (212) may be in the form of a crucible which is capable of holding a source material in the form of a powder. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Qi and would be motivated to place the powdered source material in a crucible placed on the susceptor (106) during sublimation growth according to the method of Grenet in order to provide a means for containing the powdered source material such that it can be readily inserted and removed from the deposition system.
Claim(s) 29 is/are rejected under 35 U.S.C. 103 as being unpatentable over Grenet in view of Burst and further in view of Murata and still further in view of Rakita and even further in view of U.S. Patent No. 3,969,182 to Richard C. Carlston (“Carlston”).
Regarding claim 29, Grenet, Burst, and Murata do not teach the antisolvent vapor crystallization process as claimed. However, as noted supra with respect to the rejection of claim 1, Rakita teaches an antisolvent vapor crystallization process which comprises:
dissolving a starting material in a first solvent with continuous stirring for a predetermined amount of time to form a solution, the starting material comprising elements of the single crystals of the source material (see the Precursor Solution Preparation at p. 5718 and Figs. S1-S2 which teach CsBr and PbBr2 powders are dissolved in a solvent of DMSO while stirring at 50 °C in air);
filtering the solution (see the Precursor Solution Preparation at p. 5718 and Figs. S1-S2 which teach that the saturated precursor solutions are filtered with PTFE 0.2 mm pore-size syringe filters or, alternatively, an ordinary artisan would be motivated to filter the solution in order to remove undesired particles and other potential contaminants at each stage of the process),
followed by titrating the solution with a second solvent to form a titrated solution (see the Precursor Solution Preparation at p. 5718 and Fig. S1 which teach that after cooling to room temperature the DMSO solution was titrated with MeCN or MeOH);
filtering the titrated solution to obtain a precursor solution (see the Precursor Solution Preparation at p. 5718 and Fig. S1 which teach that the saturated precursor solutions are filtered with PTFE 0.2 mm pore-size syringe filters or, alternatively, an ordinary artisan would be motivated to filter the solution in order to remove undesired particles and other potential contaminants at each stage of the process);
placing the precursor solution in a first container and covering the first container with filter paper (see the Crystal Growth protocol at pp. 5718-19 and Fig. S2 which teach that the filtered precursor solution is placed in a clean flask and covered with filter paper);
placing the first container covered with filter paper in a second container that comprises an antisolvent, and sealing the second container with the first container covered with filter paper therein (see the Crystal Growth protocol at pp. 5718-19 and Fig. S2 which teach that the covered flask was placed in a deeper, flat-bottomed glass dish which contained MeCN or MeOH as an antisolvent and sealing the top of the glass dish with filter paper);
placing the sealed second container in a furnace at a predetermined temperature, wherein the single crystals grow in the first container (see the Crystal Growth protocol at pp. 5718-20 and Fig. S2 which teach that the glass dish is placed on a hot plate and heated to a predetermined temperature in order to grow CsPbBr3 single crystals); and
removing the first container from the second container, thereby giving the prepared single crystals of the source material (after the crystal growth process as detailed in the Crystal Growth protocol at pp. 5718-19 and Fig. S2 the crystallization flask is necessarily removed from the glass dish in order to recover the grown CsPbBr3 single crystals).
Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Rakita and would recognize that the CsPbBr3 single crystals utilized in the method of Grenet, Burst, and Murata may be produced by the antisolvent vapor crystallization process as claimed with the motivation for doing so being to utilize a lower cost and readily available method to quickly produce high quality CsPbBr3 single crystals as the source material.
Grenet, Burst, Murata, and Rakita do not explicitly teach that the single crystals in the first container are washed with a third solvent. However, in col. 2, l. 9 to col. 4, l. 13 Carlston teaches an analogous method of growing single crystals by a process which involves precipitation and growth from a heated solution comprised of DMSO. In col. 3, ll. 5-22 Carlston specifically teaches that after crystal growth has completed the grown crystals can be removed from solution by a decantation process which involves, inter alia, washing the crystals with an inert solvent such as xylene and drying on filter paper. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to remove the CsPbBr3 crystals produced in the method of Grenet, Burst, Murata, and Rakita from the growth solution after the completion of crystal growth using a process which involves washing the crystals using a third inert solvent followed by drying on filter paper in order to provide a source of clean and dry CsPbBr3 single crystals which are free of potential contaminants.
Response to Arguments
Applicants’ arguments filed January 13, 2026, have been fully considered, but they are not persuasive and are moot in view of the new grounds of rejection set forth in this Office Action. Rakita and Carlston are introduced to teach the limitations in amended claim 1 and new claim 29.
Applicants repeat their argument that Burst does not teach controlling a first temperature, a second temperature, and a time of a CSS process such that a grain size of a film is the same as the thickness of the film. See applicants’ 1/13/2026 reply, pp. 6-7. Applicants’ argument is noted, but remains unpersuasive. As explained at pp. 9-10 of the Response to Arguments section of the August 13, 2025, non-final Office Action, even if Burst does not explicitly come out and state that the grain size is controlled via the duration of film growth, this is a process which is inherent to the growth of polycrystalline materials. The preferential growth of larger-sized grains and those with preferred crystal structures or crystallographic planes necessarily occurs with increasing thickness due to the occurrence of processes such as Ostwald ripening where larger particles are more energetically favored than smaller particles due to, inter alia, the reduced surface area of larger particles. This is evident from, for example, at least ¶[0166] of Grenet which teaches that grain growth occurs via the process of germination, nucleation, and then growth. This process is time-dependent which means that one of the variables controlling the grain size is the duration of film growth. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Grenet and Burst and would recognize that the grain size during CSS growth of a polycrystalline thin film may be controlled by adjusting the temperature of the substrate and the target as well as the duration of film growth and that these may be optimized through routine experimentation in order to produce a film having the desired thickness and grain size, including a grain size the same as the thickness as recited in the context of claim 1.
Applicants arguments that the cited references do not teach the use of an antisolvent vapor crystallization process are noted. Id. at p. 7. However, these arguments are moot in view of the introduction of Rakita and Carlston to teach the newly added claim limitations.
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