Macroscopic versus microscopic photovoltaic response of heterojunctions based on mechanochemically prepared nanopowders of kesterite and n-type semiconductors

• Published in: Semiconductor Physics Quantum Electronics & Optoelectronics
• Date: 2017
• Main Authors: Dimitriev, O.P., Grynko, D.O., Fedoryak, A.M., Doroshenko, T.P., Kratzer, M., Teichert, C., Noskov, Yu.V., Ogurtsov, N.A., Pud, A.A., Balaz, P., Balaz, M., Tesinsky, M.
• Format: Article
• Language: English
• Published: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2017
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/215000
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Macroscopic versus microscopic photovoltaic response of heterojunctions based on mechanochemically prepared nanopowders of kesterite and n-type semiconductors / O.P. Dimitriev, D.O. Grynko, A.M. Fedoryak, T.P. Doroshenko, M. Kratzer, C. Teichert, Yu.V. Noskov, N.A. Ogurtsov, A.A. Pud, P. Balaz, M. Balaz, M. Tesinsky // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2017. — Т. 20, № 4. — С. 418-423. — Бібліогр.: 19 назв. — англ.

Mechanochemically prepared nanopowder of selenium-free kesterite Cu₂ZnSnS₄ (CZTS) in combination with n-type semiconductors, i.e., CdS, ZnO, and TiO₂, was tested in planar and bulk-heterojunction solar cells. The samples have been studied by macroscopic current-voltage (I-V) measurements and Kelvin-probe atomic force microscopy (KPFM). KPFM images taken under light illumination showed the distribution of the potential across the surface, with negative potential on the n-type semiconductor domains and positive potential on the CZTS domains, which indicated charge separation at the interface of the counterparts. The best result was found for the CdS-CZTS composition, which showed a potential difference between the domains up to 250 mV. These results were compared with planar heterojunctions of CdS/CZTS and TiO₂/CZTS, in which CZTS nanopowder was pressed/deposited directly onto the surfaces of films of the corresponding n-type semiconductors. Again, I-V characteristics showed that cells based on CdS/CZTS heterojunctions have the best performance, with a photovoltage up to 200 mV and photocurrent densities up to 0.1 mA/cm². However, the carrier generation was found to occur mainly in the CdS semiconductor, while CZTS showed no photo-response and served as the hole-transporting layer only. It is concluded that sensitization of the kesterite powder obtained by the mechanochemical method is necessary to improve the performance of the corresponding solar cells.