With rapid advances in the development of new conjugated polymers, non-fullerene acceptors, the power conversion efficiency (PCE) of OPVs has been increased over 14%. However, a major drawback for the commercialization of OPVs is their long-term stability under continuous operation. Especially, OPVs suffer from a rapid decrease in PCE during initial device operation, which is known as the “burn-in loss”. It is considered that the origin of the burn-in loss is mainly related with the instability of the BHJ morphology and/or interface rather than the photooxidation of the photoactive layer. We find that the photoactive layer prepared by a sequential solution deposition is more stable than that prepared by blend solution deposition. We also find that the burn-in loss is closely related with stability of photoactive layer / electron transporting layer interface.
{"title":"Reducing burn-in loss in organic photovoltaics by enhancing the morphological and interfacial stability (Conference Presentation)","authors":"Kyungkon Kim","doi":"10.1117/12.2531612","DOIUrl":"https://doi.org/10.1117/12.2531612","url":null,"abstract":"With rapid advances in the development of new conjugated polymers, non-fullerene acceptors, the power conversion efficiency (PCE) of OPVs has been increased over 14%. However, a major drawback for the commercialization of OPVs is their long-term stability under continuous operation. Especially, OPVs suffer from a rapid decrease in PCE during initial device operation, which is known as the “burn-in loss”. It is considered that the origin of the burn-in loss is mainly related with the instability of the BHJ morphology and/or interface rather than the photooxidation of the photoactive layer. We find that the photoactive layer prepared by a sequential solution deposition is more stable than that prepared by blend solution deposition. We also find that the burn-in loss is closely related with stability of photoactive layer / electron transporting layer interface.","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123033838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuan Xiong, Eshwar Ravishankar, Jennifer E. Swift, H. Ade, Ronald E Booth, Melodi Charles, Reece Henry, B. O’Connor, J. Rech, C. Saravitz, H. Sederoff, L. Ye, W. You
Semi-transparent Organic Solar Cells for Greenhouse Application Yuan Xiong1*, Eshwar Ravishankar2, Jennifer Swift3, Harald Ade1*, Ronald Booth2, Melodi Charles4, Reece Henry1, Brendan O’Connor2, Jeromy James Rech5, Carole Saravitz3, Heike Sederoff4, Long Ye1, Wei You5 1. Department of Physics, Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh, NC 27695, USA 2. Department of Mechanical and Aerospace Engineering and ORaCEL, North Carolina State University, Raleigh, NC 27695, USA 3. Department of Plant Biology, North Carolina State University, Raleigh, NC 27695, USA 4. Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA 5. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA E-mail: yxiong8@ncsu.edu; hwade@ncsu.edu Semitransparent organic solar cells (ST-OSCs) show great potential in building-integrated photovoltaics due to the advantages in solution processability, flexibility, and transparency. Herein, we present a systematic study on the application of high-performance ST-OSC filters in a greenhouse by utilizing three representative systems with different spectral responses, namely, FTAZ:PC71BM[1], FTAZ:IT-M[2, 3], and PTB7-Th:IEICO-4F[4]. Specifically, the cultivation of red leaf lettuce is conducted in a controlled environment growth chamber, which is possible to duplicate any climate, and under different ST-OSC filters. In principle, the ST-OSCs absorb a portion of the solar spectrum for power generation and lettuce utilizes the penetrated light for photosynthesis. Furthermore, we quantitatively investigate the leaf area and number profiles, plant biomass, and photosynthetic rate under the as-prepared ST-OSC filters treatments. On the base of statistical analysis after the growth cycle, we can identify the best ST-OSC for plant growth. These results thus pave the way to integrate ST-OSCs with greenhouses. [1] S. C. Price, A. C. Stuart, L. Yang, H. Zhou, W. You, Journal of the American Chemical Society 2011, 133, 4625. [2] L. Ye, Y. Xiong, Q. Zhang, S. Li, C. Wang, Z. Jiang, J. Hou, W. You, H. Ade, Advanced Materials 2018, 30, 1705485. [3] Y. Xiong, L. Ye, A. Gadisa, Q. Zhang, J. J. Rech, W. You, H. Ade, Advanced Functional Materials 2019, 29, 1806262. [4] X. Song, N. Gasparini, L. Ye, H. Yao, J. Hou, H. Ade, D. Baran, ACS Energy Letters 2018, 3, 669.
应用于温室的透明有机太阳能电池:袁雄1*，Eshwar Ravishankar2, Jennifer swif3, Harald Ade1*， Ronald Booth2, Melodi Charles4, Reece Henry1, Brendan O 'Connor2, jerome James Rech5, Carole Saravitz3, Heike Sederoff4，叶龙1，优伟51。北卡罗来纳州立大学物理系，有机与碳电子实验室(ORaCEL)，北卡罗来纳州罗利27695，美国a22 .北卡罗来纳州立大学机械与航空航天工程系与ORaCEL，美国北卡罗来纳州罗利27695美国北卡罗来纳州立大学植物生物系，罗利276954 .北卡罗来纳州立大学植物与微生物学系，北卡罗来纳州罗利27695北卡罗来纳大学教堂山分校化学系，美国北卡罗来纳教堂山27599 e -mail: yxiong8@ncsu.edu;hwade@ncsu.edu半透明有机太阳能电池(ST-OSCs)由于其在溶液可加工性、灵活性和透明度方面的优势，在建筑集成光伏发电中显示出巨大的潜力。本文采用FTAZ:PC71BM[1]、FTAZ:IT-M[2,3]和PTB7-Th:IEICO-4F[4]三个具有代表性的光谱响应系统，系统研究了高性能ST-OSC滤波器在温室中的应用。具体而言，红叶莴苣的培养是在可控环境的生长室内进行的，可以复制任何气候，并在不同的ST-OSC过滤器下进行。原则上，ST-OSCs吸收一部分太阳光谱用于发电，生菜利用穿透的光进行光合作用。此外，我们定量研究了制备的ST-OSC过滤器处理下的叶面积和叶数分布、植物生物量和光合速率。在生长周期结束后的统计分析基础上，我们可以确定植物生长的最佳ST-OSC。这些结果为将ST-OSCs与温室相结合铺平了道路。[1] s c价格,a·c·斯图亚特·l·杨h .周w .你,2011年美国化学学会杂志》,133年,4625年。[2]叶磊，熊艳，张强，李树生，王超，蒋志强，侯建军，游伟，阿德红，2018 .[3]熊艳，叶丽丽，张强，李建军，尤伟，阿德华，高性能材料，2019,29 (4):662 - 662 .[4]宋晓霞，叶丽丽，姚海燕，侯俊杰，艾德H.，巴兰D.，能源工程学报，2018,36,669。
{"title":"Semi-transparent organic solar cells for greenhouse application (Conference Presentation)","authors":"Yuan Xiong, Eshwar Ravishankar, Jennifer E. Swift, H. Ade, Ronald E Booth, Melodi Charles, Reece Henry, B. O’Connor, J. Rech, C. Saravitz, H. Sederoff, L. Ye, W. You","doi":"10.1117/12.2529997","DOIUrl":"https://doi.org/10.1117/12.2529997","url":null,"abstract":"Semi-transparent Organic Solar Cells for Greenhouse Application\u0000\u0000Yuan Xiong1*, Eshwar Ravishankar2, Jennifer Swift3, Harald Ade1*, Ronald Booth2, Melodi Charles4, Reece Henry1, Brendan O’Connor2, Jeromy James Rech5, Carole Saravitz3, Heike Sederoff4, Long Ye1, Wei You5\u00001. Department of Physics, Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh, NC 27695, USA\u00002. Department of Mechanical and Aerospace Engineering and ORaCEL, North Carolina State University, Raleigh, NC 27695, USA \u00003. Department of Plant Biology, North Carolina State University, Raleigh, NC 27695, USA\u00004. Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA \u00005. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA\u0000E-mail: yxiong8@ncsu.edu; hwade@ncsu.edu\u0000\u0000 Semitransparent organic solar cells (ST-OSCs) show great potential in building-integrated photovoltaics due to the advantages in solution processability, flexibility, and transparency. Herein, we present a systematic study on the application of high-performance ST-OSC filters in a greenhouse by utilizing three representative systems with different spectral responses, namely, FTAZ:PC71BM[1], FTAZ:IT-M[2, 3], and PTB7-Th:IEICO-4F[4]. Specifically, the cultivation of red leaf lettuce is conducted in a controlled environment growth chamber, which is possible to duplicate any climate, and under different ST-OSC filters. In principle, the ST-OSCs absorb a portion of the solar spectrum for power generation and lettuce utilizes the penetrated light for photosynthesis. Furthermore, we quantitatively investigate the leaf area and number profiles, plant biomass, and photosynthetic rate under the as-prepared ST-OSC filters treatments. On the base of statistical analysis after the growth cycle, we can identify the best ST-OSC for plant growth. These results thus pave the way to integrate ST-OSCs with greenhouses. \u0000\u0000[1] S. C. Price, A. C. Stuart, L. Yang, H. Zhou, W. You, Journal of the American Chemical Society 2011, 133, 4625.\u0000[2] L. Ye, Y. Xiong, Q. Zhang, S. Li, C. Wang, Z. Jiang, J. Hou, W. You, H. Ade, Advanced Materials 2018, 30, 1705485.\u0000[3] Y. Xiong, L. Ye, A. Gadisa, Q. Zhang, J. J. Rech, W. You, H. Ade, Advanced Functional Materials 2019, 29, 1806262.\u0000[4] X. Song, N. Gasparini, L. Ye, H. Yao, J. Hou, H. Ade, D. Baran, ACS Energy Letters 2018, 3, 669.","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127910997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huawei Hu, L. Ye, Masoud Ghasemi, Nrup Balar, J. Rech, W. You, Samuel J. Stuard, B. O’Connor, H. Ade
{"title":"Rational strategies to stabilize the morphology of non-fullerene organic solar cells (Conference Presentation)","authors":"Huawei Hu, L. Ye, Masoud Ghasemi, Nrup Balar, J. Rech, W. You, Samuel J. Stuard, B. O’Connor, H. Ade","doi":"10.1117/12.2529990","DOIUrl":"https://doi.org/10.1117/12.2529990","url":null,"abstract":"","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116834290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Gahlmann, K. Brinkmann, C. Tückmantel, T. Becker, Junjie He, Johannes Bahr, C. Kreusel, T. Riedl
Aqueous dispersions of silver nanowires state an environmentally friendly avenue for highly conductive, yet transparent top electrodes for semi-transparent perovskite solar cells. However, for the well-known chemical instability of halide perovskites upon exposure to water, there are no reports of successful aqueous processing on top of perovskite devices. Here, we show that electron extraction layers of AZO/SnOx [1,2], with the SnOx grown by low temperature atomic layer deposition, provide outstanding protection layers, which even afford the spray coating of AgNW electrodes (sheet resistance Rsh =15 Ohm/sq and a transmittance of 90%) from water-based dispersions without damage to the perovskite. The layer sequence of the inverted cells is ITO/PTAA/perovskite/PCBM/AZO/SnOx/top-electrode. In devices without the ALD SnOx, aqueous spray processing decomposes the perovskite layers. Interestingly, the direct interface of Ag-NW/SnOx comprises a Schottky barrier, with characteristics strongly dependent on the charge carrier density of the SnOx. For a carrier density below 10^18 cm^-3, S-shaped J-V characteristics are found, that successively vanish upon UV-light soaking. For our low-T SnOx with 10^16 cm^-3, the insertion of a thin interfacial layer with a high charge carrier density (10^20 cm^-3), e.g. 10nm of ITO, is found to afford high performance semitransparent PSCs with an efficiency of 15%. Most importantly, compared to ITO electrodes Ag-NW based electrodes provide a key to achieve a higher transmittance in the IR, which is desirable for tandem Si/PSCs. [1] K. Brinkmann et al., Nat. Commun. 8, 13938 (2017). [2] L. Hoffmann et al. ACS Applied Mater. & Interfaces 10, 6006 (2018).
{"title":"Aqueous processing of Ag-nanowire electrodes on top of semi-transparent perovskite solar cells (Conference Presentation)","authors":"T. Gahlmann, K. Brinkmann, C. Tückmantel, T. Becker, Junjie He, Johannes Bahr, C. Kreusel, T. Riedl","doi":"10.1117/12.2529331","DOIUrl":"https://doi.org/10.1117/12.2529331","url":null,"abstract":"Aqueous dispersions of silver nanowires state an environmentally friendly avenue for highly conductive, yet transparent top electrodes for semi-transparent perovskite solar cells. However, for the well-known chemical instability of halide perovskites upon exposure to water, there are no reports of successful aqueous processing on top of perovskite devices. Here, we show that electron extraction layers of AZO/SnOx [1,2], with the SnOx grown by low temperature atomic layer deposition, provide outstanding protection layers, which even afford the spray coating of AgNW electrodes (sheet resistance Rsh =15 Ohm/sq and a transmittance of 90%) from water-based dispersions without damage to the perovskite.\u0000The layer sequence of the inverted cells is ITO/PTAA/perovskite/PCBM/AZO/SnOx/top-electrode. In devices without the ALD SnOx, aqueous spray processing decomposes the perovskite layers. Interestingly, the direct interface of Ag-NW/SnOx comprises a Schottky barrier, with characteristics strongly dependent on the charge carrier density of the SnOx. For a carrier density below 10^18 cm^-3, S-shaped J-V characteristics are found, that successively vanish upon UV-light soaking. For our low-T SnOx with 10^16 cm^-3, the insertion of a thin interfacial layer with a high charge carrier density (10^20 cm^-3), e.g. 10nm of ITO, is found to afford high performance semitransparent PSCs with an efficiency of 15%. Most importantly, compared to ITO electrodes Ag-NW based electrodes provide a key to achieve a higher transmittance in the IR, which is desirable for tandem Si/PSCs. \u0000[1] K. Brinkmann et al., Nat. Commun. 8, 13938 (2017).\u0000[2] L. Hoffmann et al. ACS Applied Mater. & Interfaces 10, 6006 (2018).","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116469170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
All solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved distinguished power conversion efficiency (PCE) to over 23% and further improvements are expected up to 25%. These novel organometal halide perovskite absorbers which possess exceptionally strong and broad light absorption enable to approach the performances of the best thin film technologies. To commercialize these great solar cells, there are many bottlenecks such as long-term stability, large scale fabrication process, and environmental issues. In this presentation, we introduce our recent efforts to improve long term stability and solve environmental issues, which will facilitate commercialization of Perovskite photovoltaic system. For examples, we introduce a recycling technology of perovskite solar cells, which will facilitate the commercialization as well as solve the environmental issues of perovskite solar cells. Also, we are going to show new interfacial layers and highly crystalline SnO2 nanoparticle layers for electron transport layer. Also, we will show a large scale coating methodology for enabling large size module fabrication by using a new solvent extractor, anisole. Also, stability issue of perovskite materials regarding charge generation and extraction will be discussed.
{"title":"Novel materials and process toward commercialization of perovskite solar cells (Conference Presentation)","authors":"H. Jung","doi":"10.1117/12.2529907","DOIUrl":"https://doi.org/10.1117/12.2529907","url":null,"abstract":"All solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved distinguished power conversion efficiency (PCE) to over 23% and further improvements are expected up to 25%. These novel organometal halide perovskite absorbers which possess exceptionally strong and broad light absorption enable to approach the performances of the best thin film technologies. To commercialize these great solar cells, there are many bottlenecks such as long-term stability, large scale fabrication process, and environmental issues. \u0000In this presentation, we introduce our recent efforts to improve long term stability and solve environmental issues, which will facilitate commercialization of Perovskite photovoltaic system. For examples, we introduce a recycling technology of perovskite solar cells, which will facilitate the commercialization as well as solve the environmental issues of perovskite solar cells. Also, we are going to show new interfacial layers and highly crystalline SnO2 nanoparticle layers for electron transport layer. Also, we will show a large scale coating methodology for enabling large size module fabrication by using a new solvent extractor, anisole. Also, stability issue of perovskite materials regarding charge generation and extraction will be discussed.","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121738129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, non-fullerene n-type organic semiconductors (n-OS) have attracted significant attention as acceptors in organic photovoltaics (OPVs) due to their great potential to realize high power conversion efficiencies (PCEs). In this regard, a rational design of central fused ring unit of the n-OS molecules is crucial to maximize the state-of-the-art PCEs. Here, we report a new class of n-OS acceptor, Y series, that employ a ladder-type electron-deficient-core-based central fused ring to fine tune its absorption and energy levels. Among these new acceptors, the Y6-based OPVs exhibit a high efficiency of 15.7 % (both in conventional or inverted structures), and a certified efficiency of 14.9 % by an inverted structure. The electron-deficient-core-based fused ring reported in this work opens a new way in the molecular design of high performance n-OS acceptors for OPVs. References: [1] Nat. Commun., 2019, 10: 570 [2] Adv.Mater., 2019, 31: 1807577 [3] Joule, 2019, 4:1140-1151
{"title":"New molecular design towards high performance single junction organic solar cell (Conference Presentation)","authors":"Y. Zou","doi":"10.1117/12.2542105","DOIUrl":"https://doi.org/10.1117/12.2542105","url":null,"abstract":"Recently, non-fullerene n-type organic semiconductors (n-OS) have attracted significant attention as acceptors in organic photovoltaics (OPVs) due to their great potential to realize high power conversion efficiencies (PCEs). In this regard, a rational design of central fused ring unit of the n-OS molecules is crucial to maximize the state-of-the-art PCEs. Here, we report a new class of n-OS acceptor, Y series, that employ a ladder-type electron-deficient-core-based central fused ring to fine tune its absorption and energy levels. Among these new acceptors, the Y6-based OPVs exhibit a high efficiency of 15.7 % (both in conventional or inverted structures), and a certified efficiency of 14.9 % by an inverted structure. The electron-deficient-core-based fused ring reported in this work opens a new way in the molecular design of high performance n-OS acceptors for OPVs.\u0000\u0000 \u0000\u0000References:\u0000[1] Nat. Commun., 2019, 10: 570\u0000[2] Adv.Mater., 2019, 31: 1807577\u0000[3] Joule, 2019, 4:1140-1151","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129936558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exciton binding energy and dielectric effect in small molecular and polymeric photovoltaic materials (Conference Presentation)","authors":"S. Tsang","doi":"10.1117/12.2528570","DOIUrl":"https://doi.org/10.1117/12.2528570","url":null,"abstract":"","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124850656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Rech, N. Bauer, David Dirkes, J. Kaplan, Huotain Zhang, Zhengxing Peng, L. Ye, Shubin Liu, H. Ade, F. Gao, W. You
Newly developed fused-ring electron acceptors (FREAs) have proven to be an effective class of materials for extending the absorption window and boosting the efficiency of organic photovoltaics (OPVs). While numerous FREA small molecules have been developed, there is surprisingly little structural diversity among high performance FREAs in literature. For example, of the high efficiency electron acceptors reported, the vast majority utilize derivatives of 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (INCN) as the acceptor moiety. It has been postulated that the high electron mobility exhibited by FREA molecules with INCN end groups is a result of close π-π stacking between the neighboring planar INCN groups, forming an effective charge transport pathway between molecules. To explore this as a design rationale for electron acceptors, we synthesized a new fused-ring electron acceptor, IDTCF, which has methyl substituents out of plane to the conjugated acceptor backbone. These methyl groups hinder packing and expand the π-π stacking distance by ~ 1 A, but this change doesn’t affect the optical or electrochemical properties of the individual acceptor molecule. Overall, our results show that intermolecular interactions (especially π-π stacking between end groups) play a crucial role in performance of FREAs. We demonstrated that the planarity of the acceptor unit is of paramount importance as even minor deviations in end group distance are enough to disrupt crystallinity and cripple device performance.
{"title":"The crucial role of end group planarity for fused-ring electron acceptors in organic solar cells (Conference Presentation)","authors":"J. Rech, N. Bauer, David Dirkes, J. Kaplan, Huotain Zhang, Zhengxing Peng, L. Ye, Shubin Liu, H. Ade, F. Gao, W. You","doi":"10.1117/12.2529500","DOIUrl":"https://doi.org/10.1117/12.2529500","url":null,"abstract":"Newly developed fused-ring electron acceptors (FREAs) have proven to be an effective class of materials for extending the absorption window and boosting the efficiency of organic photovoltaics (OPVs). While numerous FREA small molecules have been developed, there is surprisingly little structural diversity among high performance FREAs in literature. For example, of the high efficiency electron acceptors reported, the vast majority utilize derivatives of 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (INCN) as the acceptor moiety. It has been postulated that the high electron mobility exhibited by FREA molecules with INCN end groups is a result of close π-π stacking between the neighboring planar INCN groups, forming an effective charge transport pathway between molecules. To explore this as a design rationale for electron acceptors, we synthesized a new fused-ring electron acceptor, IDTCF, which has methyl substituents out of plane to the conjugated acceptor backbone. These methyl groups hinder packing and expand the π-π stacking distance by ~ 1 A, but this change doesn’t affect the optical or electrochemical properties of the individual acceptor molecule. Overall, our results show that intermolecular interactions (especially π-π stacking between end groups) play a crucial role in performance of FREAs. We demonstrated that the planarity of the acceptor unit is of paramount importance as even minor deviations in end group distance are enough to disrupt crystallinity and cripple device performance.","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115301316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A critical component of any donor-acceptor (D-A) bulk heterojunction organic solar cell is the appearance of inter-molecular charge-transfer (CT) electronic states at their D-A interfaces. These electronic states play a determining role in the photo-physical processes that transform the energy of the absorbed sunlight into electrical power. Here, through integrated multiscale theoretical simulations, we have illustrated how factors such as the details of the molecular packing at the D-A interfaces, the electronic polarization effects, and the extent of electron/hole delocalization around the interface impact the nature of the CT states. Moreover, we have also discussed how the hybridization between the CT and local-exciton (LE) states impacts the spectroscopy characteristics of D-A blends, the recombination rates and consequently the voltage losses, which need to be minimized.
{"title":"The role of donor-acceptor interfacial charge-transfer (CT) electronic states in photoelectric energy conversion in organic solar cells (Conference Presentation)","authors":"Xian-Kai Chen","doi":"10.1117/12.2528967","DOIUrl":"https://doi.org/10.1117/12.2528967","url":null,"abstract":"A critical component of any donor-acceptor (D-A) bulk heterojunction organic solar cell is the appearance of inter-molecular charge-transfer (CT) electronic states at their D-A interfaces. These electronic states play a determining role in the photo-physical processes that transform the energy of the absorbed sunlight into electrical power. Here, through integrated multiscale theoretical simulations, we have illustrated how factors such as the details of the molecular packing at the D-A interfaces, the electronic polarization effects, and the extent of electron/hole delocalization around the interface impact the nature of the CT states. Moreover, we have also discussed how the hybridization between the CT and local-exciton (LE) states impacts the spectroscopy characteristics of D-A blends, the recombination rates and consequently the voltage losses, which need to be minimized.","PeriodicalId":342552,"journal":{"name":"Organic, Hybrid, and Perovskite Photovoltaics XX","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122509017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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