本研究以水熱以及溶劑熱法合成具有形狀控制之鈦酸鋇奈米晶體，以進行光學與壓電晶面效應研究。在改變不同溶劑、前驅物濃度以及反應溫度與時間條件下，尺寸可調之鈦酸鋇立方體(邊長自132奈米至438 奈米)、117奈米之{110}與{111}截角、截邊立方體，以及126奈米之八面體被成功合成。在電子顯微鏡下，此三種形狀之鈦酸鋇奈米晶體皆展現均勻之尺寸與形貌。由X光繞射光譜、穿透式電子顯微鏡，佐以Rietveld結構精算，可得此三種形貌之晶體皆為單晶結構，且具有微幅之晶格常數差異。而拉曼光譜則近一步證實此三種晶體屬正方晶系。在光學性質量測上，鈦酸鋇立方體之吸收峰隨晶體尺寸變小而藍移，而相近體積之鈦酸鋇立方體、截角、截邊立方體與八面體也展現了吸收值位移之現象。此三種形狀之晶體在壓電力顯微鏡量測下，亦展現出不同程度之壓電響應，以及不同程度之矯頑電場強度。此三種鈦酸鋇奈米晶體亦被用於壓電奈米發電機之製作。元件表現上，聚二甲基矽氧烷(Polydimethylsiloxane, PDMS)混合重量百分濃度30之鈦酸鋇八面體粉末之元件，展現了最佳輸出開路電壓與短路電流值，分別為23伏特與324奈安培。此元件亦在串聯60百萬歐姆外加電阻下，達最佳輸出功率3.9微瓦。

In this work, BaTiO3 cubes (132 to 438 nm), 117 nm {110} and {111}-truncated cubes, and 126 nm octahedra have been successfully synthesized for facet-dependent optical and piezoelectric property examination. Electron microscopy images show that the nanocrystals have sharp faces and high size and shape uniformity. PXRD and TEM characterization, supported by Rietveld refinement, were performed to establish the BaTiO3 lattice parameters, showing slight shape-related peak shifts. Raman spectra were used to confirm that the BaTiO3 particles possess a tetragonal crystal structure. Band gaps of the BaTiO3 crystals show both size and facet dependence. Amplitude-voltage butterfly loops and phase-voltage hysteresis loops in the piezo response force microscopy (PFM) measurements on single particles display facet dependence. Additionally, piezoelectric nanogenerators were successfully fabricated by using polydimethylsiloxane (PDMS) polymer and BaTiO3 nanocrystals. The flexible piezoelectric nanogenerator with 30 wt% BaTiO3 octahedra exhibited the highest output performance with an output open-circuit voltage of 23.0 V and a short-circuit current of 324 nA under a periodic mechanical bend-release mode. More importantly, effective power of 3.9 μW was achieved at a load resistance of 60 MΩ.

(1) Huang, M. H.; Kumar, G. Origin and manifestation of semiconductor facet effects. J. Chin. Chem. Soc. 2022.
(2) Ho, J.-Y.; Huang, M. H. Synthesis of Submicrometer-Sized Cu2O Crystals with Morphological Evolution from Cubic to Hexapod Structures and Their Comparative Photocatalytic Activity. J. Phys. Chem. C 2009, 113 (32), 14159-14164.
(3) Lyu, L.-M.; Wang, W.-C.; Huang, M. H. Synthesis of Ag2O nanocrystals with systematic shape evolution from cubic to hexapod structures and their surface properties. Chem. Eur. J. 2010, 16 (47), 14167-141674.
(4) Wu, J.-K.; Lyu, L.-M.; Liao, C.-W.; Wang, Y.-N.; Huang, M. H. Fast synthesis of PbS nanocrystals in aqueous solution with shape evolution from cubic to octahedral structures and their assembled structures. Chem. Eur. J. 2012, 18 (45), 14473-14478.
(5) Hsieh, M.-S.; Su, H.-J.; Hsieh, P.-L.; Chiang, Y.-W.; Huang, M. H. Synthesis of Ag3PO4 Crystals with Tunable Shapes for Facet-Dependent Optical Property, Photocatalytic Activity, and Electrical Conductivity Examinations. ACS Appl. Mater. Interfaces 2017, 9 (44), 39086-39093.
(6) Hsieh, P.-L.; Naresh, G.; Huang, Y.-S.; Tsao, C.-W.; Hsu, Y.-J.; Chen, L.-J.; Huang, M. H. Shape-Tunable SrTiO3 Crystals Revealing Facet-Dependent Optical and Photocatalytic Properties. J. Phys. Chem. C 2019, 123 (22), 13664-13671.
(7) Peng, Y.-W.; Wang, C.-P.; Kumar, G.; Hsieh, P.-L.; Hsieh, C.-M.; Huang, M. H. Formation of CsPbCl3 Cubes and Edge-Truncated Cuboids at Room Temperature. ACS Sustainable Chem. Eng. 2022, 10 (4), 1578-1584.
(8) Huang, M. H.; Chiu, C.-Y. Achieving polyhedral nanocrystal growth with systematic shape control. J. Mater. Chem. A 2013, 1 (28), 8081–8092.
(9) Tan, C.-S.; Huang, M. H. Surface-dependent band structure variations and bond-level deviations in Cu2O. Inorg. Chem. Front. 2021, 8 (18), 4200-4208.
(10) Tan, C.-S.; Chen, Y.-J.; Hsia, C.-F.; Huang, M. H. Facet-Dependent Electrical Conductivity Properties of Silver Oxide Crystals. Chem. Asian J. 2017, 12 (3), 293-297.
(11) Hsieh, P.-L.; Madasu, M.; Hsiao, C.-H.; Peng, Y.-W.; Chen, L.-J.; Huang, M. H. Facet-Dependent and Adjacent Facet-Related Electrical Conductivity Properties of SrTiO3 Crystals. J. Phys. Chem. C 2021, 125 (18), 10051-10056.
(12) Tan, C.-S.; Chen, H.-S.; Chiu, C.-Y.; Wu, S.-C.; Chen, L.-J.; Huang, M. H. Facet-Dependent Electrical Conductivity Properties of PbS Nanocrystals. Chem. Mater. 2016, 28 (5), 1574-1580.
(13) Tan, C.-S.; Hsu, S.-C.; Ke, W.-H.; Chen, L.-J.; Huang, M. H. Facet-dependent electrical conductivity properties of Cu2O crystals. Nano Lett. 2015, 15 (3), 2155-2160.
(14) Tan, C.-S.; Hsieh, P.-L.; Chen, L.-J.; Huang, M. H. Silicon Wafers with Facet-Dependent Electrical Conductivity Properties. Angew. Chem. Int. Ed. 2017, 56 (48), 15339-15343.
(15) Hsieh, P.-L.; Lee, A.-T.; Chen, L.-J.; Huang, M. H. Germanium Wafers Possessing Facet-Dependent Electrical Conductivity Properties. Angew. Chem. Int. Ed. 2018, 57 (49), 16162-16165.
(16) Hsieh, P.-L.; Wu, S.-H.; Liang, T.-Y.; Chen, L.-J.; Huang, M. H. GaAs wafers possessing facet-dependent electrical conductivity properties. J. Mater. Chem. C 2020, 8 (16), 5456-5460.
(17) Hsieh, P.-L.; Kumar, G.; Wang, Y.-Y.; Lu, Y.-J.; Chen, L.-J.; Huang, M. H. Facet-dependent electrical conductivity properties of GaN wafers. J. Mater. Chem. C 2021, 9 (42), 15354-15358.
(18) Tan, C.-S.; Huang, M. H. Metal-like Band Structures of Ultrathin Si {111} and {112} Surface Layers Revealed through Density Functional Theory Calculations. Chem. Eur. J. 2017, 23 (49), 11866-11871.
(19) Tan, C.-S.; Huang, M. H. Density Functional Theory Calculations Revealing Metal-like Band Structures for Ultrathin Germanium (111) and (211) Surface Layers. Chem. Asian J. 2018, 1972 –1976.
(20) Tan, C.-S.; Huang, M. H. Surface-dependent band structure variations and bond deviations of GaN. Phys. Chem. Chem. Phys. 2022, 24 (16), 9135-9140.
(21) Y. P. Varshni. Temperature dependence of the energy gap in semiconductors. Physica 1967, 34 (1), 149-155.
(22) Cox, P. A. The electronic structure and chemistry of solids; Oxford 1987.
(23) Yang, Z.-L.; Kumar, G.; Huang, M. H. Synthesis of Zinc Blende-Phased CdSe Nanocrystals with Size-Tunable Optical Properties and Adjustable Valence Band Positions. Langmuir 2022, 38 (8), 2729-2736.
(24) Wu, S.-H.; Hsiao, C.-H.; Hsieh, P.-L.; Huang, X.-F.; Huang, M. H. Growth of CeO2 nanocubes showing size-dependent optical and oxygen evolution reaction behaviors. Dalton Trans. 2021, 50 (42), 15170-15175.
(25) Huang, Y.-C.; Wu, S.-H.; Hsiao, C.-H.; Lee, A.-T.; Huang, M. H. Mild Synthesis of Size-Tunable CeO2 Octahedra for Band Gap Variation. Chem. Mater. 2020, 32 (6), 2631-2638.
(26) Chang, C.-H.; Madasu, M.; Wu, M.-H.; Hsieh, P.-L.; Huang, M. H. Formation of size-tunable CuI tetrahedra showing small band gap variation and high catalytic performance towards click reactions. J. Colloid Interface Sci. 2021, 591, 1-8.
(27) Hsiao, C.-H.; Chen, C.-W.; Chen, H.-S.; Hsieh, P.-L.; Chen, Y.-A.; Huang, M. H. Formation of size-tunable CdS rhombic dodecahedra. J. Mater. Chem. C 2021, 9 (18), 5992-5997.
(28) Huang, M. H. Facet-Dependent Optical Properties of Semiconductor Nanocrystals. Small 2019, 15 (7), 1804726.
(29) Huang, M. H. Semiconductor nanocrystals possessing broadly size‐ and facet‐dependent optical properties. J. Chin. Chem. Soc. 2020, 68 (1), 45-50.
(30) Ke, W.-H.; Hsia, C.-F.; Chen, Y.-J.; Huang, M. H. Synthesis of Ultrasmall Cu2O Nanocubes and Octahedra with Tunable Sizes for Facet-Dependent Optical Property Examination. Small 2016, 12 (26), 3530–3534.
(31) Huang, J.-Y.; Madasu, M.; Huang, M. H. Modified Semiconductor Band Diagrams Constructed from Optical Characterization of Size-Tunable Cu2O Cubes, Octahedra, and Rhombic Dodecahedra. J. Phys. Chem. C 2018, 122 (24), 13027-13033.
(32) Yang, Y.-C.; Peng, Y.-W.; Lee, A.-T.; Kumar, G.; Huang, M. H. CsPbBr3 and CsPbI3 rhombic dodecahedra and nanocubes displaying facet-dependent optical properties. Inorg. Chem. Front. 2021, 8 (21), 4685-4695.
(33) Tan, C. S.; Hsu, S. C.; Ke, W. H.; Chen, L. J.; Huang, M. H. Facet-dependent electrical conductivity properties of Cu2O crystals. Nano Lett. 2015, 15 (3), 2155-2160.
(34) Jona, F.; Shirane, G. Ferroelectric Crystals; Oxford, 1962.
(35) Huan, Y.; Wang, X.; Fang, J.; Li, L. Grain size effect on piezoelectric and ferroelectric properties of BaTiO3 ceramics. J. Eur. Ceram. Soc. 2014, 34 (5), 1445-1448.
(36) Frey, M. H.; Payne, D. A. Grain-size effect on structure and phase transformations for barium titanate. Phys. Rev. B 1996, 54, 3158–3168.
(37) McCauley, D.; Newnham, R. E.; Randall, C. A. Intrinsic Size Effects in a Barium Titanate Glass-Ceramic. J. Amer. Ceram. Soc. 1998, 81 (4), 979–987.
(38) Zhao, Z.; Buscaglia, V.; Viviani, M.; Buscaglia, M. T.; Mitoseriu, L.; Testino, A.; Nygren, M.; Johnsson, M.; Nanni, P. Grain-size effects on the ferroelectric behavior of dense nanocrystalline BaTiO3 ceramics. Phys. Rev. B 2004, 70, 024107.
(39) Shaw, T. M.; Trolier-McKinstry, S.; McIntyre, P. C. The Properties of Ferroelectric Films at Small Dimensions. Annu. Rev. Mater. Sci. 2000, 30, 263-298.
(40) Takaaki, T. T., Hoshina Hiroaki, Takeda Youichi, Mizuno Hirokazu, Chazono. Size Effect of Barium Titanate and Computer-Aided Design of Multilayered Ceramic Capacitors. IEEE Trans. Ultraso. Ferroelectr. Freq. Control 2009, 56 (8),1513-1522.
(41) Hu, D.; Yao, M.; Fan, Y.; Ma, C.; Fan, M.; Liu, M. Strategies to achieve high performance piezoelectric nanogenerators. Nano Energy 2019, 55, 288-304.
(42) Bhavanasi, V.; Kumar, V.; Parida, K.; Wang, J.; Lee, P. S. Enhanced Piezoelectric Energy Harvesting Performance of flexible PVDF-TrFE Bilayer Films with Graphene Oxide. ACS Appl. Mater. Interfaces 2016, 8 (1), 521-529.
(43) Guo, J.; Zhao, X.; Herisson De Beauvoir, T.; Seo, J. H.; Berbano, S. S.; Baker, A. L.; Azina, C.; Randall, C. A. Recent Progress in Applications of the Cold Sintering Process for Ceramic–Polymer Composites. Adv. Funct. Mater. 2018, 28 (39), 1801724
(44) Jin, W.; Wang, Z.; Huang, H.; Hu, X.; He, Y.; Li, M.; Li, L.; Gao, Y.; Hu, Y.; Gu, H. High-performance piezoelectric energy harvesting of vertically aligned Pb(Zr,Ti)O3 nanorod arrays. RSC Adv. 2018, 8 (14), 7422-7427.
(45) Ni, X.; Wang, F.; Lin, A.; Xu, Q.; Yang, Z.; Qin, Y. Flexible Nanogenerator Based on Single BaTiO3 Nanowire. Sci. Adv. Mater. 2013, 5 (11), 1781-1787.
(46) Wang, Q.; Yang, D.; Qiu, Y.; Zhang, X.; Song, W.; Hu, L. Two-dimensional ZnO nanosheets grown on flexible ITO-PET substrate for self-powered energy-harvesting nanodevices. Appl. Phys. Lett. 2018, 112 (6), 063906.
(47) Wang, Z. L.; Song, J. Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays. Science 2006, 312 (5771), 242-246.
(48) Xu, Q.; Wen, J.; Qin, Y. Development and outlook of high output piezoelectric nanogenerators. Nano Energy 2021, 86, 106080.
(49) Park, K. I.; Jeong, C. K.; Kim, N. K.; Lee, K. J. Stretchable piezoelectric nanocomposite generator. Nano Converg. 2016, 3 (1), 12.
(50) Yang, R.; Qin, Y.; Dai, L.; Wang, J.; Wang, Z. L. Power generation with laterally packaged piezoelectric fine wires. Nat. Nanotechnol. 2009, 4 (1), 34-39.
(51) Wu, W.; Bai, S.; Yuan, M.; Qin, Y.; Wang, Z. L.; Jing, T. Lead Zirconate Titanate Nanowire Textile Nanogenerator for Wearable Energy-Harvesting and Self-Powered Devices. ACS Nano 2012, 6 (7), 6231-6235.
(52) Bai, S.; Xu, Q.; Gu, L.; Ma, F.; Qin, Y.; Wang, Z. L. Single crystalline lead zirconate titanate (PZT) nano/micro-wire based self-powered UV sensor. Nano Energy 2012, 1 (6), 789-795.
(53) Park, K.-I.; Xu, S.; Liu, Y.; Hwang, G.-T.; Kang, S.-J. L.; Wang, Z. L.; Lee, K. J. Piezoelectric BaTiO3 thin film nanogenerator on plastic substrates. Nano Lett. 2010, 10 (12), 4939–4943.
(54) Lin, Z.-H.; Yang, Y.; Wu, J. M.; Liu, Y.; Zhang, F.; Wang, Z. L. BaTiO3 Nanotubes-Based Flexible and Transparent Nanogenerators. J. Phys. Chem. Lett. 2012, 3 (23), 3599-3604.
(55) Khan, A.; Ali Abbasi, M.; Hussain, M.; Hussain Ibupoto, Z.; Wissting, J.; Nur, O.; Willander, M. Piezoelectric nanogenerator based on zinc oxide nanorods grown on textile cotton fabric. Appl. Phys. Lett. 2012, 101 (19), 193506.
(56) Zhu, G.; Yang, R.; Wang, S.; Wang, Z. L. Flexible high-output nanogenerator based on lateral ZnO nanowire array. Nano Lett. 2010, 10 (8), 3151-3155.
(57) Kumar, B.; Lee, K. Y.; Park, H.-K.; Chae, S. J.; Lee, Y. H.; Kim, S.-W. Controlled Growth of Semiconducting Nanowire, Nanowall, and Hybrid Nanostructures on Graphene for Piezoelectric Nanogenerators. ACS Nano 2011, 5 (5), 4197-4204.
(58) Shin, S.-H.; Choi, S.-Y.; Lee, M. H.; Nah, J. High-Performance Piezoelectric Nanogenerators via Imprinted Sol-Gel BaTiO3 Nanopillar Array. ACS Appl. Mater. Interfaces 2017, 9 (47), 41099-41103.
(59) Zhang, Y.; Liu, C.; Liu, J.; Xiong, J.; Liu, J.; Zhang, K.; Liu, Y.; Peng, M.; Yu, A.; Zhang, A.; et al. Lattice Strain Induced Remarkable Enhancement in Piezoelectric Performance of ZnO-Based Flexible Nanogenerators. ACS Appl. Mater. Interfaces 2016, 8 (2), 1381-1387.
(60) Liu, C.; Yu, A.; Peng, M.; Song, M.; Liu, W.; Zhang, Y.; Zhai, J. Improvement in the Piezoelectric Performance of a ZnO Nanogenerator by a Combination of Chemical Doping and Interfacial Modification. J. Phys. Chem. C 2016, 120 (13), 6971-6977.
(61) Hsu, C.-L.; Su, I. L.; Hsueh, T.-J. Sulfur-doped-ZnO-nanospire-based transparent flexible nanogenerator self-powered by environmental vibration. RSC Adv. 2015, 5 (43), 34019-34026.
(62) Wang, X. B.; Song, C.; Li, D. M.; Geng, K. W.; Zeng, F.; Pan, F. The influence of different doping elements on microstructure, piezoelectric coefficient and resistivity of sputtered ZnO film. Appl. Surf. Sci. 2006, 253 (3), 1639-1643.
(63) Zhu, D.; Hu, T.; Zhao, Y.; Zang, W.; Xing, L.; Xue, X. High-performance self-powered/active humidity sensing of Fe-doped ZnO nanoarray nanogenerator. Sens. Actuators B: Chem. 2015, 213, 382-389.
(64) Sinha, N.; Ray, G.; Bhandari, S.; Godara, S.; Kumar, B. Synthesis and enhanced properties of cerium doped ZnO nanorods. Ceram. Int. 2014, 40 (8), 12337-12342.
(65) Jing, Y.; Young, G. J. High Performance Flexible Piezoelectric Nanogenerators based on BaTiO3 Nanofibers in Different Alignment Modes. ACS Appl. Mater. Interfaces 2016, 8 (24), 15700-15709.
(66) Lee, S.; Lee, J.; Ko, W.; Cha, S.; Sohn, J.; Kim, J.; Park, J.; Park, Y.; Hong, J. Solution-processed Ag-doped ZnO nanowires grown on flexible polyester for nanogenerator applications. Nanoscale 2013, 5 (20), 9609-9614.
(67) Park, K. I.; Lee, M.; Liu, Y.; Moon, S.; Hwang, G. T.; Zhu, G.; Kim, J. E.; Kim, S. O.; Kim, D. K.; Wang, Z. L.; et al. Flexible nanocomposite generator made of BaTiO3 nanoparticles and graphitic carbons. Adv. Mater. 2012, 24 (22), 2999-3004, 2937.
(68) Zhao, Y.; Liao, Q.; Zhang, G.; Zhang, Z.; Liang, Q.; Liao, X.; Zhang, Y. High output piezoelectric nanocomposite generators composed of oriented BaTiO3 NPs@PVDF. Nano Energy 2015, 11, 719-727.
(69) Zhang, M.; Gao, T.; Wang, J.; Liao, J.; Qiu, Y.; Xue, H.; Shi, Z.; Xiong, Z.; Chen, L. Single BaTiO3 nanowires-polymer fiber based nanogenerator. Nano Energy 2015, 11, 510-517.
(70) Meng, X.; Zhang, Z.; Lin, D.; Liu, W.; Zhou, S.; Ge, S.; Su, Y.; Peng, C.; Zhang, L. Effects of particle size of dielectric fillers on the output performance of piezoelectric and triboelectric nanogenerators. J. Adv. Ceram. 2021, 10 (5), 991-1000.
(71) Park, K. I.; Bae, S. B.; Yang, S. H.; Lee, H. I.; Lee, K.; Lee, S. J. Lead-free BaTiO3 nanowires-based flexible nanocomposite generator. Nanoscale 2014, 6 (15), 8962-8968.
(72) Yao, M.; Li, L.; Wang, Y.; Yang, D.; Miao, L.; Wang, H.; Liu, M.; Ren, K.; Fan, H.; Hu, D. Mechanical Energy Harvesting and Specific Potential Distribution of a Flexible Piezoelectric Nanogenerator Based on 2-D BaTiO3-Oriented Polycrystals. ACS Sustain. Chem. Eng. 2022, 10 (10), 3276-3287.
(73) Toby, B. H.; Von Dreele, R. B. GSAS-II: the genesis of a modern open-source all purpose crystallography software package. J. Appl. Cryst. 2013, 46 (2), 544-549.
(74) Crystallography Open Database. http://www.crystallography.net/cod/search.html (accessed July 2022).
(75) Blanco-López, M. C.; Fourlaris, G.; Rand, B.; Riley, F. L. Characterization of barium titanate powders: Barium carbonate identification. J. Am. Ceram. Soc. 1999, 82 (7), 1777–1786.
(76) Usher, T.-M.; Kavey, B.; Caruntu, G.; Page, K. Effect of BaCO3 Impurities on the Structure of BaTiO3 Nanocrystals: Implications for Multilayer Ceramic Capacitors. ACS Appl. Nano Mater. 2020, 3 (10), 9715-9723.
(77) Miot, C.; Husson, E.; Proust, C.; Erre, R.; Coutures, J. P. X-ray photoelectron spectroscopy characterization of barium titanate ceramics prepared by the citric route. Residual carbon study. J. Mater. Res. 1997, 12 (9), 2388-2392.
(78) XRD pattern of Barium Titanate BaTiO3 Nanopowder / Nanoparticles (BaTiO3, 99.9%, 500nm, Tetragonal). https://www.us-nano.com/inc/sdetail/416 (accessed 2022 July).
(79) Young, R. A. The Rietveld Methods; Oxford University Press Inc., 1993.
(80) Begg, B. D.; Finnie, K. S.; Vance, E. R. Raman Study of the Relationship between Room-Temperature Tetragonality and the Curie Point of Barium Titanate. J. Am. Ceram. Soc. 1996, 79 (10), 2666-2672.
(81) Asiaie, R.; Zhu, W.; Akbar, S. A.; Dutta, P. K. Characterization of Submicron Particles of Tetragonal BaTiO3. Chem. Mater. 1996, 8 (1), 226-234.
(82) Shiratori, Y.; Pithan, C.; Dornseiffer, J.; Waser, R. Raman scattering studies on nanocrystalline BaTiO3 Part I—isolated particles and aggregates. J. Raman Spectrosc. 2007, 38 (10), 1288-1299.
(83) Fontana, M. P.; Lambert, M. Linear disorder and temperature dependence of Raman scattering in BaTiO3. Solid State Commun. 1972, 10 (1), 1-4.
(84) Quittet, A. M.; Lambert, M. Temperature dependence of the Raman cross section and light absorption in cubic BaTiO3. Solid State Commun. 1973, 12 (10), 1053-1055.
(85) Zhang, H.; Cheng, B.; Li, Q.; Liu, B.; Mao, Y. Morphology-Tuned Phase Transitions of Horseshoe Shaped BaTiO3 Nanomaterials under High Pressure. J. Phys. Chem. C 2018, 122 (9), 5188-5194.
(86) Makula, P.; Pacia, M.; Macyk, W. How To Correctly Determine the Band Gap Energy of Modified Semiconductor Photocatalysts Based on UV-Vis Spectra. J. Phys. Chem. Lett. 2018, 9 (23), 6814-6817.
(87) Kim, H. S.; Lee, D. W.; Kim, D. H.; Kong, D. S.; Choi, J.; Lee, M.; Murillo, G.; Jung, J. H. Dominant Role of Young's Modulus for Electric Power Generation in PVDF-BaTiO3 Composite-Based Piezoelectric Nanogenerator. Nanomaterials (Basel) 2018, 8 (10), 777
(88) Yang, R.; Qin, Y.; Li, C.; Dai, L.; Wang, Z. L. Characteristics of output voltage and current of integrated nanogenerators. Appl. Phys. Lett. 2009, 94 (2), 022905