72
M. Hiramoto
3.5 Conclusion
Using percolation to form crystalline–amorphous nanocomposites of blended films
between donor and acceptor molecules (which offers individual transport routes
for electrons and holes) by the elevated substrate temperature during co-deposition
enhances the photovoltaic performance.
The vertical superlattice junctions have ability to collect both excitons and carriers
although the area of the vertical superlattice junction is very small.
The lateral multilayered junctions using high-mobility organic semiconductors
are able to collect both excitons and carriers and have sufficient cell area. Therefore,
the lateral junction can be regarded as an alternative blended junction for organic
solar cells.
Acknowledgements Funding from the New Energy and Industrial Technology Development Organization (NEDO) is appreciated. Financial support from JSPS, KAKENHI (No. 17H02768) is gratefully acknowledged. The author appreciates A. Adachi and S. Ohashi of EpiTech Co. (Kyoto, Japan)
for the design and construction of the movable mask system.
References
1. Hiramoto, M., Fujiwara, H., Yokoyama, M.: Three-layered organic solar cell with a photoactive
interlayer of codeposited pigment. Appl. Phys. Lett. 58, 1062–1064 (1991)
2. Yu, G., Gao, J., Hummelen, J.C., Wudl, F., Heeger, A.J.: Polymer photovoltaic cells enhanced
efficiencies via a network of internal donor-acceptor heterojunctions. Science 270, 1789–1791
(1995)
3. Maennig, B.,Drechsel, J., Gebeyehu, D., Simon, P., Kozlowski, F., Werner, A., Li, F., Grundmann, S., Sonntag, S., Koch, M., Leo, K., Pfeiffer, M., Hoppe, H., Meissner, D., Sariciftci, N.
S.,Riedel, I., Dyakonov, V., Parisi, J.: Organic p-i-n solar cells. Appl. Phys. A,79, 1–14 (2004)
4. Riede, M., Uhrich, C., Widmer, J., Timmreck, R., Wynands, D., Schwartz, G., Gnehr, W.M.,
Hildebrandt, D., Weiss, A., Hwang, J., Sundarraj, S., Erk, P., Pfeiffer, M., Leo, K.: Efficient
organic tandem solar cells based on small molecules. Adv. Funct. Mater. 21, 3019–3028 (2011)
5. Li, W.N., Ye, L., Li, S. S., Yao, H. F., Ade, H., Hou, J. H.:A high-efficiency organic solar cell
enabled by the strong intramolecular electron push-pull effect of the nonfullerene acceptor.
Adv. Mater.,30, 1707170(8 pages) (2018)
6. Osaka, I., Saito, M., Koganezawa, T., Takimiya, K.: Thiophene-thiazolothiazole copolymers: significant impact of side chain composition on backbone orientation and solar cell
performances. Adv. Mater. 26, 331–338 (2014)
7. Kaji, T., Zhang, M., Nakao, S., Iketaki, K., Yokoyama, K., Tang, C.W., Hiramoto, M.: Coevaporant induced crystalline donor:acceptor blends in organic solar cells. Adv. Mater. 23,
3320–3325 (2011)
8. Hiramoto, M.: Organic solar cells incorporating a p-i-n junction and a p-n homojunction. In:
Sun, S.-S., Sariciftci, N.S. (eds.) Organic photovoltaics, Mechanisms, Materials and Devices,
pp. 239–270. CRC Press, New York (2005)
9. Spanggaard, H., Krebs, F.C.: A brief history of the development of organic and polymeric
photovoltaics. Sol. Energy Mater. Sol. Cells 83, 125–146 (2004)
10. Tang, C.W.: Two-layer organic photovoltaic cell. Appl. Phys. Lett. 48, 183–185 (1986)
11. Walzer, K., Maennig, B., Pfeiffer, M., Leo, K.: Highly efficient organic devices based on
electrically doped transport layers. Chem. Rev. 107, 1233–1271 (2007)
M. Hiramoto
3.5 Conclusion
Using percolation to form crystalline–amorphous nanocomposites of blended films
between donor and acceptor molecules (which offers individual transport routes
for electrons and holes) by the elevated substrate temperature during co-deposition
enhances the photovoltaic performance.
The vertical superlattice junctions have ability to collect both excitons and carriers
although the area of the vertical superlattice junction is very small.
The lateral multilayered junctions using high-mobility organic semiconductors
are able to collect both excitons and carriers and have sufficient cell area. Therefore,
the lateral junction can be regarded as an alternative blended junction for organic
solar cells.
Acknowledgements Funding from the New Energy and Industrial Technology Development Organization (NEDO) is appreciated. Financial support from JSPS, KAKENHI (No. 17H02768) is gratefully acknowledged. The author appreciates A. Adachi and S. Ohashi of EpiTech Co. (Kyoto, Japan)
for the design and construction of the movable mask system.
References
1. Hiramoto, M., Fujiwara, H., Yokoyama, M.: Three-layered organic solar cell with a photoactive
interlayer of codeposited pigment. Appl. Phys. Lett. 58, 1062–1064 (1991)
2. Yu, G., Gao, J., Hummelen, J.C., Wudl, F., Heeger, A.J.: Polymer photovoltaic cells enhanced
efficiencies via a network of internal donor-acceptor heterojunctions. Science 270, 1789–1791
(1995)
3. Maennig, B.,Drechsel, J., Gebeyehu, D., Simon, P., Kozlowski, F., Werner, A., Li, F., Grundmann, S., Sonntag, S., Koch, M., Leo, K., Pfeiffer, M., Hoppe, H., Meissner, D., Sariciftci, N.
S.,Riedel, I., Dyakonov, V., Parisi, J.: Organic p-i-n solar cells. Appl. Phys. A,79, 1–14 (2004)
4. Riede, M., Uhrich, C., Widmer, J., Timmreck, R., Wynands, D., Schwartz, G., Gnehr, W.M.,
Hildebrandt, D., Weiss, A., Hwang, J., Sundarraj, S., Erk, P., Pfeiffer, M., Leo, K.: Efficient
organic tandem solar cells based on small molecules. Adv. Funct. Mater. 21, 3019–3028 (2011)
5. Li, W.N., Ye, L., Li, S. S., Yao, H. F., Ade, H., Hou, J. H.:A high-efficiency organic solar cell
enabled by the strong intramolecular electron push-pull effect of the nonfullerene acceptor.
Adv. Mater.,30, 1707170(8 pages) (2018)
6. Osaka, I., Saito, M., Koganezawa, T., Takimiya, K.: Thiophene-thiazolothiazole copolymers: significant impact of side chain composition on backbone orientation and solar cell
performances. Adv. Mater. 26, 331–338 (2014)
7. Kaji, T., Zhang, M., Nakao, S., Iketaki, K., Yokoyama, K., Tang, C.W., Hiramoto, M.: Coevaporant induced crystalline donor:acceptor blends in organic solar cells. Adv. Mater. 23,
3320–3325 (2011)
8. Hiramoto, M.: Organic solar cells incorporating a p-i-n junction and a p-n homojunction. In:
Sun, S.-S., Sariciftci, N.S. (eds.) Organic photovoltaics, Mechanisms, Materials and Devices,
pp. 239–270. CRC Press, New York (2005)
9. Spanggaard, H., Krebs, F.C.: A brief history of the development of organic and polymeric
photovoltaics. Sol. Energy Mater. Sol. Cells 83, 125–146 (2004)
10. Tang, C.W.: Two-layer organic photovoltaic cell. Appl. Phys. Lett. 48, 183–185 (1986)
11. Walzer, K., Maennig, B., Pfeiffer, M., Leo, K.: Highly efficient organic devices based on
electrically doped transport layers. Chem. Rev. 107, 1233–1271 (2007)