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Polymer Journal (2026)
Organic photovoltaics (OPVs) that operate efficiently under both outdoor and indoor conditions remain challenging because the governing requirements for spectral absorption, energy-level alignment, and recombination suppression differ fundamentally among these conditions. Here, we report a pyrimido[5,4-d]pyrimidine (PyPy)-based π-conjugated polymer, P(PyPy-BDT), as a versatile wide-bandgap donor enabling dual-mode OPVs. The incorporation of the strongly electron-deficient PyPy unit deepens the HOMO level, resulting in high open-circuit voltages of up to 0.93 and 1.21 V when combined with the nonfullerene acceptors IT-4F and IO-4F, respectively. Under standard 1-sun illumination, P(PyPy-BDT):IT-4F-based devices achieved a higher power conversion efficiency (PCE) of 9.3% compared with the corresponding IO-4F-based devices. In contrast, under indoor dim-light conditions, the performance trend was reversed: P(PyPy-BDT):IO-4F-based devices delivered a high PCE of 20.0%, outperforming IT-4F-based devices under a white LED at 1000 lx. This inversion originates from the combined effects of spectral matching, energetic alignment, and recombination dynamics, which govern device operation differently under distinct illumination conditions. These results highlight the illumination-dependent nature of OPV performance and provide a general design guideline for dual-mode OPVs, offering a viable pathway toward high-performance indoor energy harvesting.
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Li S, Xu LD, Zhao S. The internet of things: a survey. Inf Syst Front. 2015;17:243–59.
Article Google Scholar
Lim H-R, Kim HS, Qazi R, Kwon Y-T, Jeong J-W, Yeo W-H. Advanced soft materials, sensor integrations, and applications of wearable flexible hybrid electronics in healthcare, energy, and environment. Adv Mater. 2020;32:1901924.
Article CAS Google Scholar
Shi J, Liu S, Zhang L, Yang B, Shu L, Yang Y, et al. Smart textile-integrated microelectronic systems for wearable applications. Adv Mater. 2020;32:1901958.
Article CAS Google Scholar
Xu C, Song Y, Han M, Zhang H. Portable and wearable self-powered systems based on emerging energy harvesting technology. Microsyst Nanoeng. 2021;7:1–14.
Article CAS Google Scholar
Yu G, Gao J, Hummelen JC, Wudl F, Heeger AJ. Polymer photovoltaic cells: enhanced efficiencies via a network of internal donor-acceptor heterojunctions. Science. 1995;270:1789–91.
Article CAS Google Scholar
Li G, Zhu R, Yang Y. Polymer solar cells. Nat Photonics. 2012;6:153–61.
Article CAS Google Scholar
Huang Y, Kramer EJ, Heeger AJ, Bazan GC. Bulk heterojunction solar cells: morphology and performance relationship. Chem Rev. 2014;114:7006–43.
Article CAS PubMed Google Scholar
Lu L, Zheng T, Wu Q, Schneider AM, Zhao D, Yu L. Recent advances in bulk heterojunction polymer solar cells. Chem Rev. 2015;115:12666–731.
Article CAS PubMed Google Scholar
Hou J, Inganäs O, Friend RH, Gao F. Organic solar cells based on non-fullerene acceptors. Nat Mater. 2018;17:119–28.
Article CAS PubMed Google Scholar
Best Research-Cell Efficiencies, The National Renewable Energy Laboratory (NREL): https://www.nrel.gov/pv/cell-efficiency.html. Accessed Apr 2026.
Li C, Yao G, Gu X, Lv J, Hou Y, Lin Q, et al. Highly efficient organic solar cells enabled by suppressing triplet exciton formation and non-radiative recombination. Nat Commun. 2024;15:8872.
Article CAS PubMed PubMed Central Google Scholar
Zhu L, Zhang M, Zhou G, Wang Z, Zhong W, Zhuang J, et al. Achieving 20.8% organic solar cells via additive-assisted layer-by-layer fabrication with bulk p-i-n structure and improved optical management. Joule. 2024;8:3153–68.
Article CAS Google Scholar
Mathews I, Kantareddy SN, Buonassisi T, Peters IM. Technology and market perspective for indoor photovoltaic cells. Joule. 2019;3:1415–26.
Article CAS Google Scholar
Pecunia V, Occhipinti LG, Hoye RLZ. Emerging indoor photovoltaic technologies for sustainable internet of things. Adv Energy Mater. 2021;11:2100698.
Article CAS Google Scholar
Li M, Igbari F, Wang Z-K, Liao L-S. Indoor thin-film photovoltaics: progress and challenges. Adv Energy Mater. 2020;10:2000641.
Article CAS Google Scholar
Hwang S, Yasuda T. Indoor photovoltaic energy harvesting based on semiconducting π-conjugated polymers and oligomeric materials toward future IoT applications. Polym J. 2023;55:297–316.
Article CAS Google Scholar
Cui Y, Hong L, Hou J. Organic photovoltaic cells for indoor applications: opportunities and challenges. ACS Appl Mater Interfaces. 2020;12:38815–28.
Article CAS PubMed Google Scholar
Hou X, Wang Y, Lee HKH, Datt R, Miano NU, Yan D, et al. Indoor application of emerging photovoltaics–progress, challenges and perspectives. J Mater Chem A. 2020;8:21503–25.
Article CAS Google Scholar
Saeed MA, Kim SH, Kim H, Liang J, Woo HY, Kim TG, et al. Indoor organic photovoltaics: optimal cell design principles with synergistic parasitic resistance and optical modulation effect. Adv Energy Mater. 2021;11:2003103.
Article CAS Google Scholar
Jahandar M, Kim S, Lim DC. Indoor organic photovoltaics for self-sustaining IoT devices: progress, challenges and practicalization. ChemSusChem. 2021;14:3449–74.
Article CAS PubMed PubMed Central Google Scholar
Arai R, Furukawa S, Hidaka Y, Komiyama H, Yasuda T. High-performance organic energy-harvesting devices and modules for self-sustainable power generation under ambient indoor lighting environments. ACS Appl Mater Interfaces. 2019;11:9259–64.
Article CAS PubMed Google Scholar
Arai R, Furukawa S, Sato N, Yasuda T. Organic energy-harvesting devices achieving power conversion efficiencies over 20% under ambient indoor lighting. J Mater Chem A. 2019;7:20187–92.
Article CAS Google Scholar
Bai F, Zhang J, Zeng A, Zhao H, Duan K, Yu H, et al. A highly crystalline non-fullerene acceptor enabling efficient indoor organic photovoltaics with high EQE and fill factor. Joule. 2021;5:1231–45.
Article CAS Google Scholar
Zheng B, Huo L, Li Y. Benzodithiophenedione-based polymers: recent advances in organic photovoltaics. NPG Asia Mater. 2020;12:3.
Article CAS Google Scholar
An C, Hou J. Benzo[1,2-b:4,5-b′]dithiophene-based conjugated polymers for highly efficient organic photovoltaics. Acc Mater Res. 2022;3:540–51.
Article CAS Google Scholar
Cevher D, Cevher SC, Cirpan A. Recently developed benzodithiophene based organic solar cells: A review on materials and strategies. Mater Today Commun. 2023;37:107524.
Article CAS Google Scholar
Zhou D, Wang Y, Yang S, Quan J, Deng J, Wang J, et al. Recent advances of benzodithiophene-based donor materials for organic solar cells. Small. 2024;20:2306854.
Article CAS Google Scholar
Wei M, Perepichka DF. Benzodithiophene-based polymer donors for organic photovoltaics. J Mater Chem A. 2025;13:12785–807.
Article CAS Google Scholar
Xu X, Yu T, Bi Z, Ma W, Li Y, Peng Q. Realizing over 13% efficiency in green-solvent-processed nonfullerene organic solar cells enabled by 1,3,4-thiadiazole-based wide-bandgap copolymers. Adv Mater. 2018;30:1703973.
Article Google Scholar
Zhang T, An C, Bi P, Lv Q, Qin J, Hong J, et al. A thiadiazole-based conjugated polymer with ultradeep HOMO level and strong electroluminescence enables 18.6% efficiency in organic solar cell. Adv Energy Mater. 2021;11:2101705.
Article CAS Google Scholar
Zhang T, Cui Y, Zhang J, Bi P, Yang C, Zhang S, et al. A universal nonhalogenated polymer donor for high-performance organic photovoltaic cells. Adv Mater. 2022;34:2105803.
Article CAS Google Scholar
Guo B, Li W, Meng X, Ma W, Zhang M, Li Y. A wide-bandgap conjugated polymer for highly efficient inverted single and tandem polymer solar cells. J Mater Chem A. 2016;4:13251–113258.
Article CAS Google Scholar
Guo B, Li W, Guo X, Meng X, Ma W, Zhang M, et al. High efficiency polymer solar cells with thick active layer and large area. Adv Mater. 2017;29:1702291.
Article Google Scholar
Wu J, Li G, Fang J, Guo X, Zhu L, Guo B, et al. Random terpolymer based on thiophene-thiazolothiazole unit enabling efficient non-fullerene organic solar cells. Nat Commun. 2020;11:4612.
Article CAS PubMed PubMed Central Google Scholar
Yamanaka K, Mikie T, Osaka I. A strategically designed easily-synthesized polymer donor for efficient organic photovoltaics. Adv Energy Mater. 2025;15:2502173.
Article CAS Google Scholar
Wu J, Fan Q, Xiong M, Wang Q, Chen K, Liu H, et al. Crboxylate substituted pyrazine: A simple and low-cost building block for novel wide bandgap polymer donor enables 15.3% efficiency in organic solar cells. Nano Energy. 2021;82:105679.
Article CAS Google Scholar
Ren J, Zhang S, Bi P, Chen Z, Zhang T, Wang J, et al. An over 16% efficiency organic solar cell enabled by a low-cost pyrazine-based polymer donor. J Mater Chem A. 2022;10:25595–601.
Article CAS Google Scholar
Xu X, Feng K, Bi Z, Ma W, Zhang G, Peng Q. Single-junction polymer solar cells with 16.35% efficiency enabled by a platinum(II) complexation strategy. Adv Mater. 2019;31:1901872.
Article Google Scholar
Xu L, Tao W, Guan M, Yang X, Huang M, Chen H, et al. ACS Appl Energy Mater. 2021;4:11624–33.
Article CAS Google Scholar
Yamamoto T, Lee B-L. New soluble, coplanar poly(naphthalene-2,6-diyl)-type π-conjugated polymer, poly(pyrimido[5,4-d]pyrimidine-2,6-diyl), with nitrogen atoms at all of the o-positions. Synthesis, solid structure, optical properties, self-assembling phenomena, and redox behavior. Macromolecules. 2002;35:2993–9.
Article CAS Google Scholar
Lee B-L, Yamamoto T. Synthesis of light-emitting π-conjugated poly(pyrimido[5,4-d]pyrimidine-2,6-diyl) with bulky side chains and high molecular weight. Polymer. 2002;43:4531–4.
Article CAS Google Scholar
Fukumoto H, Takatsuki S, Lee B-L, Yamamoto T. π-Conjugated poly(pyrimido[5,4-d]pyrimidine-2,6-diyl)s with two different alkylamino groups: Synthesis, chemical properties, and structure. Synth Met. 2009;159:900–4.
Article CAS Google Scholar
Zhao W, Li S, Yao H, Zhang S, Zhang Y, Yang B, et al. Molecular optimization enables over 13% efficiency in organic solar cells. J Am Chem Soc. 2017;139:7148–51.
Article CAS PubMed Google Scholar
An analog (IO-4Cl) bearing terminal Cl groups instead of the F groups has been initially reported. See, Cui Y, Wang Y, Bergqvist J, Yao H, Xu Y, Gao B, et al. Wide-gap non-fullerene acceptor enabling high-performance organic photovoltaic cells for indoor applications. Nat Energy. 2019;4:768–75.
Article Google Scholar
Xian K, Cui Y, Xu Y, Zhang T, Hong L, Yao H, et al. Efficient exciton dissociation enabled by the end group modification in non-fullerene acceptors. J Phys Chem C. 2020;124:7691–8.
Article CAS Google Scholar
Fiduccia I, Ricci D, Rizzo C, Pibiri I. Non-canonical σ-hole interactions: halogen, chalcogen, and pnictogen bonds in biomolecular structure and drug design. Coord Chem Rev. 2026;552:217515.
Article CAS Google Scholar
Yasuda T, Sakai Y, Aramaki S, Yamamoto T. New coplanar (ABA)n-type donor-acceptor π-conjugated copolymers constituted of alkylthiophene (unit A) and pyridazine (unit B): synthesis using hexamethylditin, self-organized solid structure, and optical and electrochemical properties of the copolymers. Chem Mater. 2005;17:6060–8.
Article CAS Google Scholar
Sato N, Hwang S, Tsuchii Y, Yasuda T. Fused polycyclic lactam-based π-conjugated polymers for efficient nonfullerene organic solar cells. J Mater Chem A. 2023;11:9840–5.
Article CAS Google Scholar
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This work was supported in part by Grant-in-Aid for JSPS KAKENHI (Grant No. JP24K21248 and JP25K01848), JST CREST (Grant No. JPMJCR21O5), JFE 21st Century Foundation, Murata Science and Education Foundation, and Kuma Science Engineering and Culture Promotional Foundation. The authors thank the Cooperative Research Program of Network Joint Research Center for Materials and Devices (NJRC), the Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM) of the MEXT, and the computer facilities at the Research Institute for Information Technology, Kyushu University for their generous research support.
Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
Jiahui Duan & Takuma Yasuda
Institute for Advanced Study, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
Asumi Sueyasu & Takuma Yasuda
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Correspondence to Takuma Yasuda.
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Duan, J., Sueyasu, A. & Yasuda, T. Efficient indoor and outdoor organic photovoltaics enabled by a pyrimido[5,4-d]pyrimidine-based π-conjugated polymer. Polym J (2026). https://doi.org/10.1038/s41428-026-01199-w
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DOI: https://doi.org/10.1038/s41428-026-01199-w
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Polymer Journal (Polym J)
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