DETAILED ACTION
This is the second Office Action regarding application number 18/599,070, filed on 03/07/2024, which claims priority to application number 17/139,921, filed on 12/31/2020, which is a continuation of application number 16/010,342, filed on 06/15/2018, and which claims priority to provisional application number 62/521,211, filed on 06/16/2017.
This action is in response to the Applicant’s Response received 08/06/2025.
Status of Claims
Claims 1-16, 18, and 20 are currently pending.
Claims 17 and 19 are cancelled.
Claim 1 is amended.
Claims 1-16, 18, and 20 are examined below.
The rejection of claims under 35 U.S.C. § 103 has been withdrawn in light of the Applicant’s amendments.
Upon further examination, the Office has set forth a new ground of rejection.
No claim is allowed.
Response to Arguments
The Applicant’s arguments received 08/06/2025 have been carefully considered but they are moot in light of the Office’s new ground of rejection.
The applicant remarks that the cited prior art references do not teach or suggest the use of cyanine salts (also known as polymethines). The examiner does not rely on the previously cited prior art references to teach the cyanine salts, and adds a new prior art reference to establish a finding of obviousness of the claims.
The applicant does not identify any deficiency in the ground of rejection. The examiner asserts that each reference cited provides comprehensive reasoning and factual background that clearly explains exactly how a skilled artisan would review available references to arrive at the invention claimed.
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 1-16, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over STAUFFER (“Transparent solar cells: Generating power from everyday surfaces”) in view of LUNT (“Transparent, near-infrared organic photovoltaic solar cells for window and energy-scavenging applications”), GUO (“Imide- and Amide-Functionalized Polymer Semiconductors”), FUJIYAMA (US 2007/0219375 A1), ROSSELLI (US 2018/0057492 A1), ROGER (“Core-Tetrosubstituted Naphthalene Diimides: Synthesis, Optical Properties, and Redox Characteristics”), and LUNT-2016 (WO 2016/176008 A1).
Regarding claim 1, STAUFFER describes a visibly transparent photovoltaic device (see image below of solar cell displaying substantial transparency) comprising:
a visibly transparent substrate (“transparent substrate” in the photovoltaic device illustration provided below);
a first visibly transparent electrode (front-most “transparent electrode”) coupled to the visibly transparent substrate;
a second visibly transparent electrode (rear-most “transparent electrode”) above the first visibly transparent electrode;
a first visibly transparent active layer (“UV/NIR Active Layers”) between the first visibly transparent electrode and the second visibly transparent electrode,
wherein the first visibly transparent active layer comprises a first photoactive compound (the UV portion of the UV/NIR Active Layers),
a second visibly transparent active layer (the NIR portion of the UV/NIR Active Layers) between the first visibly transparent electrode and the second visibly transparent electrode and in direct contact with the first visibly transparent active layer (the sample device illustration below shows the UV/NIR active layers are two different layers in direct contact),
wherein the second visibly transparent active layer comprises a second photoactive compound (the Active Layers are described as having two photoactive compounds, one responsive to UV and the other responsive to NIR light).
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STAUFFER does not disclose expressly that the first photoactive compound is a UV electron acceptor having the recited structure, or that the second photoactive compound is an electron donor material, or information related to the absorption strengths.
STAUFFER, however, provides substantial information and direction that would be understood by skilled artisans as a general roadmap for the production of transparent solar cells, an advancement that “would change the rules of the game.”
STAUFFER teaches that a transparent solar cell should absorb all of the energy from the sun except the part that allows humans to see, and specifically describes that the device should absorb well in the near-infrared and the ultraviolet parts of the spectrum while in the visible region, absorption drops off, approaching zero. STAUFFER further reports that the transparent solar cells can transmit “more than 70% of the visible light”. STAUFFER does not report any specific materials used for the absorption and conversion of UV and NIR light. The examiner first asserts that this reference would inform skilled artisans of a general strategy to produce a transparent solar cell and would direct these artisans to pursue materials having the ability to absorb and convert UV and NIR light as instructed by STAUFFER.
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The examiner next asserts that the claimed limitations related to the maximum UV/NIR absorption strengths with respect to visible absorption strengths serve only to restate the inherent function of materials that absorb strongly in the UV/NIR wavelengths. A material that inherently absorbs more in the UV/NIR than the visible range will necessarily read on these respective limitations.
Thus, the only feature recited in claim 1 obviously missing from STAUFFER is the chemical structure of the UV acceptor. The examiner asserts that skilled artisans would immediately search for acceptable materials capable of UV photon conversion and intended for use in optoelectronic applications such as solar cells.
LUNT describes transparent solar cells based upon organic semiconducting materials, and describes in greater detail the concepts taught by STAUFFER (the STAUFFER reference is based largely upon the LUNT reference). For instance, LUNT describes that the active layers include an electron donor and electron acceptor.
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It would have been obvious to skilled artisans familiar with the STAUFFER reference to make necessary modifications and select the structure and materials taught by LUNT in order to construct a transparent solar cell from organic materials.
GUO describes polymer semiconductors favorable for use as active layer materials in organic solar cells. GUO reports that naphthalene diimide (NDI) polymers have potential as acceptor semiconductors in organic solar cells (pg. 8966, section 3.3, left col., para. 1). GUO describes that NDI materials may be structurally modified by varying the N-imide substituent R and functionalizing the aromatic core with different electron-donating or -accepting groups (X and Y) (Figure 8 description).
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GUO also reports that imide-functionalized molecules “constitute the most successful n-type organic semiconductors and enable their applications . . . as electron acceptor semiconductors in [organic solar cells]” (pg. 8951, section 1.4.1, left. col., para. 1).
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GUO also describe a variety of NDI-based polymer semiconductors that function as electron acceptors (Fig. 20), including materials having the claimed structure with numerous bridging groups and R groups comprising heterocyclic substituents. GUO’s P65 is included here simply as an illustrative example of the class of materials available and known to skilled artisans for selection in organic solar cells (Figure 20). As mentioned above, GUO described that the substituents connected to the aromatic core are chosen to acquire desired optical and photo-responsive properties, and that numerous options are available and known to link together the NDI core component and derivatives.
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While GUO expands on other numerous aspects of NDI materials, the authors conclude by emphasizing that NDI polymers are reported to have shown power conversion efficiency of 6.4% in all-polymer solar cells, “which is the highest in this category cell” (pg. 9012, para. bridging cols.).
It would have been obvious to skilled artisans to modify STAUFFER further, along with the teachings of LUNT, and select an electron acceptor molecule taught by GUO, such as the P65 NDI derivative, because the selection of these known NDI materials is known to have exceptional power conversion efficiency in organic solar cells, and also because their chemical structure is well-known to be capable of modification by substituent selection and functionalization in order to produce materials having desired optical and electronic properties.
FUJIYAMA teaches concepts closely related to GUO, specifically NDI compounds for organic solar cells, and reports that the disclosed compounds are superior in the ability of electron transport, have high sensitivity, and high durability (paras. 35-36). FUJIYAMA further reports that R1/R2 may comprise hydrogen (para. 35).
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It would have been obvious to skilled artisans, alternatively, to modify the prior art according to the teachings of FUJIYAMA and incorporate as first photoactive compound materials having the structures and compositions taught by FUJIYAMA, including materials where claimed bridging group B is a direct covalent bond linking together NDI structural units by the nitrogen atoms, in order to form a material having superior charge transport, optical sensitivity, and durability.
The examiner makes special note of the importance of the durability aspects considered by FUJIYAMA, since STAUFFER also notes that “one remaining challenge is longevity” and that “solar cells should be guaranteed to have a commercially viable lifespan” (pg. 24, left col.). The examiner asserts that skilled artisans having both the STAUFFER and FUJIYAMA references would be motivated to construct a transparent solar cell using a photoactive compound according to the chemical structure taught by FUJIYAMA in order to obtain a device with improved durability. With the additional knowledge and instruction provided by GUO, these skilled artisans would be capable to make additional necessary substituent and functional modifications to the NDI cores in order to achieve the desired optical transparency and absorption in the UV range.
ROSSELLI teaches concepts closely related to FUJIYAMA, specifically NDI dimer compounds for organic solar cells (paras. 21 and 25), and reports that the disclosed compounds are superior in electron mobility, have high sensitivity, and high thermal durability, excellent photostability (paras. 249-256). ROSSELLI further recognizes expressly that the energy levels and thin film morphology are directly affected by the type of substituents in the bridge component (para. 249).
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It would have been obvious to skilled artisans, alternatively, to modify the prior art according to the teachings of ROSSELLI and incorporate as first photoactive compound materials having the structures and compositions taught by ROSSELLI, including materials where claimed bridging group B is one of ROSSELLI’s bridge units linking together NDI structural units by the nitrogen atoms, in order to form a material having superior charge mobility, optical sensitivity, durability, and photostability. This would be a logical and straightforward modification of the N—N covalent bond to instead include of the bridge groups taught by ROSSELLI. Skilled artisans would recognize that this modification would allow for the fine-tuning of the energy levels and film morphology because the prior art expressly recognizes this effect.
ROGER teaches core-tetrasubstituted naphthalene diimides (NDIs) substantially similar to those recited by the other cited references and claimed by the applicant, and further describes the addition of NHC6H13 units at the various X positions (e.g., NDI 8). ROGER reports that in order to achieve the most red-shifted absoption maximum known for NDIs, one should add multiple NHC6H13 units (pg. 8074, conclusion section).
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Skilled artisans would have found it obvious to further modify the aforementioned references and add at least three or more NHC6H13 units at the X positions off the naphthalene core as taught by ROGER because it was known that these functional groups affect and increase the absorption maximum.
A skilled artisan having the references cited would, more likely than not, possess all of the teachings, suggestions, and motivation required to construct the visible transparent photovoltaic device recited by claim 1. The examiner concludes that the content and direction of the prior art references provide sufficient guidance to optimize, select, and substitute the known chemical compositions according to known methods to generate appropriate materials useful to improve the performance and appearance of the prior art transparent solar cells—specifically, a solar cell “transparent” to visible light that also absorbs and converts incoming UV and NIR wavelengths.
The examiner also asserts that the substituent selection and functionalization of NDI materials are considered “known techniques” to improve similar materials, and that the prior art identifies NDI materials are “ready for improvement” for the purpose of increasing conversion efficiency in transparent organic solar cells. MPEP 2143(C) and (D).
Further, it would have been obvious to skilled artisans to select the ultraviolet electron acceptor as the first photoactive compound for the first visible transparent active layer because there are only three apparent configurations available and obvious to try: (1) UV acceptor first, IR donor second, (2) IR donor first, UV acceptor second, and (3) UV acceptor and IR donor blended together. MPEP 2143(E).
The examiner notes that it is well-established that one of ordinary skill in the art is not a mindless worker capable only of rotely performing tasks from explicit instructions, but is instead a person of ordinary creativity and skill capable of critical thinking and technical analysis. See KSR, 550 U.S. at 421 (“A person of ordinary skill is also a person of ordinary creativity, not an automaton.”); see also In re Sovish, 769 F.2d 738, 743 (Fed. Cir. 1985) (presuming skill on the part of one of ordinary skill in the art); see MPEP 2141.03. Furthermore, the examiner notes that a reference is not limited to only the explicit or direct teachings set forth therein, but also inferences that one of ordinary skill in the art would be reasonably expected to draw from its teachings. See In re Preda, 401 F.2d 825, 826, 159 USPQ 342, 344 (CCPA 1968) (holding that a reference stands for all of the specific teachings thereof as well as the inferences one of ordinary skill in the art would have reasonably been expected to draw therefrom); see also MPEP 2141.03 and 2144.01.
Lastly, the examiner has reviewed the applicant’s disclosure and finds no evidence or other experimental results that suggest criticality or unexpected results of the variously claimed B, X, or R groups beyond what is already known in the art—that the selection and modification of these groups strongly influences the optical and electrical properties of NDI-based materials, and that these modifications are well-understood in the art and would be the primary focus for routine experimentation as result effective variables. MPEP 2144.05. Similarly, the compounds described by GUO have very close structural similarities and similar utilities (similar and/or expected UV absorption properties) to the composition claimed by the applicant, and therefore the examiner concludes that the claimed compositions are prima facie obvious. MPEP 2144.09; no superior or unexpected results described by the applicant’s specification.
STAUFFER also does not disclose expressly that the second photoactive compound comprises a cyanine salt.
LUNT-2016 lauds polymethines/cyanine salts as “one of the most promising classes of molecules to satisfy the need for efficient, NIR-harvesting and visibly transparent NIR- harvesting compounds. Polymethines are a class of ionic organic salts that have gained attention for photovoltaic applications due to their tunable absorption, high extinction coefficients, and high solubility. Recently, polymethines with absorption maxima in the near-infrared have been employed in OPV devices with efficiencies of 1 .5 - 2.8% for opaque devices, 0.9 - 2.2% for semitransparent devices, and transparent luminescent solar concentrators.” (para. 5).
Skilled artisans would have found it obvious to modify STAUFFER and add a cyanine salt as a second photoactive compound because cyanine salts were very well-known and appreciated for their satisfactory performance for NIR-harvesting as taught by LUNT-2016.
Regarding claim 2, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, but does not disclose expressly that the first maximum visible absorption strength is between 0.1% and 10% of the first maximum ultraviolet absorption strength.
However, the device taught by the combined prior art references is substantially, if not entirely, identical to the device recited by these dependent claim (see rejection of claim 1 above). Regarding product and apparatus claims, when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. It is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. In re Schreiber, 128 F.3d at 1478, 44 USPQ2d at 1478, 44 USPQ2d at 1432 (Fed. Cir. 1997) (see MPEP 2112.01).
Since the examiner does not have proper means to conduct experiments, the burden of proof is now shifted to applicants to show otherwise. In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977); In re Fitzgerald, 205 USPQ 594 (CCPA 1980).
Additionally, ROGER describes that the NDI 8, which possesses a chemical structure substantially identical to the claimed composition, exhibits absorption strengths at wavelengths in the visible and UV ranges that most likely fall within the relationship ranges claimed (Fig. 3).
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Regarding claim 3, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 2, but does not disclose expressly that the first maximum visible absorption strength is between 0.1% and 5% of the first maximum ultraviolet absorption strength.
However, the device taught by the combined prior art references is substantially, if not entirely, identical to the device recited by these dependent claim (see rejection of claim 1 above). Regarding product and apparatus claims, when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. It is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. In re Schreiber, 128 F.3d at 1478, 44 USPQ2d at 1478, 44 USPQ2d at 1432 (Fed. Cir. 1997) (see MPEP 2112.01).
Since the examiner does not have proper means to conduct experiments, the burden of proof is now shifted to applicants to show otherwise. In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977); In re Fitzgerald, 205 USPQ 594 (CCPA 1980).
Additionally, ROGER describes that the NDI 8, which possesses a chemical structure substantially identical to the claimed composition, exhibits absorption strengths at wavelengths in the visible and UV ranges that most likely fall within the relationship ranges claimed (Fig. 3).
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Regarding claim 4, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the first visibly transparent active layer and the second visibly transparent active layer correspond to separate, mixed, or partially mixed layers (GUO, Fig. 5 illustrates and describes the finite number of identified configurations). It would have been obvious to skilled artisans to select from the finite options and yield a solar cell with a reasonable expectation of success. MPEP 2143(E).
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Regarding claim 5, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the first photoactive compound is visibly transparent (STAUFFER reports that all of the layers and compounds are visibly transparent; ROGER provides data showing that the absorption of the material within the visible range is extremely limited, and thus would likely be visible transparent).
Regarding claim 6, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the first visibly transparent active layer is coupled to the first visibly transparent electrode or wherein the first visibly transparent active layer is coupled to the second visibly transparent electrode (STAUFFER illustrates the claimed arrangement where the active layer is coupled to either the first/front or second/rear electrode).
Regarding claim 7, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein absorption of UV light by the first photoactive compound drives formation and separation of electron-hole pairs, and wherein absorption of NIR light by the second photoactive compound drives formation and separation of electron-hole pairs (LUNT reports that the UV and NIR compounds are both sensitive to light and create charge carriers).
Regarding claim 8, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, further comprising: a first buffer layer in direct contact with the first visibly transparent active layer; or a second buffer layer in direct contact with the second visibly transparent active layer (LUNT describes the appropriateness of including an MoO3 and BCP layer in direct contact with the active layers and the electrodes, and would be obvious to add for their respect charge carrier functions).
Regarding claim 9, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the second photoactive compound comprises a boron-dipyrromethene compound, a phthalocyanine, a naphthalocyanine, a nickel dithiolate compound, a dicyano-indandione, a benzothiadiazole, a benzo-bis-thiadiazole, a diketopyrrolopyrrole diphenythienylamine, or a combination thereof (LUNT describes that a phthalocynanine is utilized in the active layer as an electron donor, pg. 113305-1).
Regarding claim 10, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein B is a phenyl linker, a 1,4 phenylenediamine linker, a thiophene linker, or a C1-C4 alkyl linker (ROSSELLI describe a variety of phenyl linkers).
Regarding claim 11, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 10, wherein at least three of X1-X8 or X9-X14 is independently NHC6H13 and each R is –H (ROGER teaches that all four of the X positions can be NHC6H13 for maximum red-shift; FUJIYAMA discloses examples where and X/R are hydrogen).
Regarding claim 12, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein each one of X1-X8 or X9-X14 is independently NHC6H13 (ROGER teaches that all four of the X positions can be NHC6H13 for maximum red-shift).
Regarding claim 13, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 12, wherein each R is independently --H or … (FUJIYAMA discloses examples where R is hydrogen).
Regarding claim 14, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein each R is independently --H, … (FUJIYAMA discloses examples where R is hydrogen).
Regarding claim 15, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 14, wherein each one of X1-X8 or X9-X14 is independently NHC6H13 (ROGER teaches that all four of the X positions can be NHC6H13 for maximum red-shift).
Regarding claim 16, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the first photoactive compound has a structure of
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The rejection grounds for claim 1 conclude that the prior art suggests the structure of claim 16.
Regarding claim 18, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, wherein the first photoactive compound has a structure of… (GUO presents materials that read on the claimed structure; ROSSELLI also describes that the bridge component may be alternatively employed elsewhere in the NDI dimer composition).
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As ROSSELLI only describes two options for the bonding bridge group of the NDI dimer (either using the nitrogen positions or the other bridgeable carbon positions), the examiner concludes that skilled artisans would find it obvious to try to modify the bridge group location to the position claimed by the applicant.
Regarding claim 20, modified STAUFFER teaches or would have suggested the visibly transparent photovoltaic device of claim 1, but does not disclose expressly that the first visibly active layer further comprises an additional photoactive compound selected from the group consisting of a naphthalenetetracarboxylic diimide, a naphthalenetetracarboxylic diimide derivative, a bisimide coronene, a bisimide coronene derivative, a fluoranthene, a fluoranthene derivative, a corannulene, a corannulene derivative, and combinations thereof.
It would have been obvious to skilled artisans to duplicate the photoactive compound in the first active layer and include another ultraviolet electron acceptor because this modification requires only a simple duplication of parts, and has no patentable significance as no new or unexpected result is produced according to the applicant’s disclosure. The prior art already describes NDI-based materials, and the simple change of incorporating another similar NDI material is considered only a duplication of parts.
Conclusion
No claim is allowed.
The 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). The Applicant is reminded of the extension of time policy as set forth in 37 C.F.R. § 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 extension fee 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.
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