Selectively patterned TiO2 nanorods as electron transport pathway for high performance perovskite solar cells

• Published in: Nano research Vol. 12; no. 3; pp. 601 - 606
• Main Authors: Huh, Daihong, Oh, KyoungSuk, Kim, Minjin, Choi, Hak-Jong, Kim, Dong Suk, Lee, Heon
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01-03-2019; Springer Nature B.V
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Carrier transport; Chemistry and Materials Science; Circuits; Coating effects; Condensed Matter Physics; Current efficiency; Efficiency; Electron transport; Energy conversion efficiency; Fabrication; Holes (electron deficiencies); Incident light; Materials Science; Nanorods; Nanotechnology; Open circuit voltage; Perovskites; Photoluminescence; Photons; Photovoltaic cells; Photovoltaics; Research Article; Solar cells; Spectroscopy; Substrates; Titanium dioxide; patterned TiO; nanoimprint lithography; nanorods; perovskite solar cells
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-018-2263-x

Organic-inorganic hybrid perovskite solar cells (PSCs) are attracting tremendous attention for new-generation photovoltaic devices because of their excellent power conversion efficiency and simple fabrication process. One of the various approaches to increase the efficiency of PSCs is to change the material or structure of the carrier transport layer. Here, optically long and electrically short structural concept is proposed to enhance the characteristics of a PSC by employing selectively grown single crystalline TiO
2
nanorods. The approach has the merit of increasing the electron-hole separation effectively and enables a thicker active layer to be coated without electrical loss by using TiO
2
nanorods as an electron pathway. Moreover, selectively grown TiO
2
nanorods increase the optical path of the incident light via scattering effects and enable a smooth coating of the active layer. Nanoimprint lithography and hydrothermal growth were employed to fabricate selectively grown TiO
2
nanorod substrates. The fabricated solar cell exhibits an efficiency of 19.86% with a current density, open-circuit voltage, and fill factor of 23.13 mA/cm
2
, 1.120 V, and 76.69%, respectively. Time-resolved photoluminescence, ultraviolet-visible (UV–Vis) spectroscopy, and the incident photon to current efficiency (IPCE) analysis were conducted to understand the factors responsible for the improvement in characteristics of the fabricated PSCs.