TY - JOUR
T1 - 80% Fill Factor in Organic Solar Cells with a Modified Nickel Oxide Interlayer
AU - Garcia Romero, David
AU - Bontekoe, Gerbrand
AU - Pinna, Jacopo
AU - Di Mario, Lorenzo
AU - Ibarra-Barreno, Carolina M.
AU - Kardula, Jane
AU - Ersek, Gabor
AU - Portale, Giuseppe
AU - Rudolf, Petra
AU - Loi, Maria Antonietta
N1 - Publisher Copyright:
© 2025 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH.
PY - 2025/1/5
Y1 - 2025/1/5
N2 - The efficiency of organic solar cells has raised drastically in the past years. However, there is an undeniable lack of hole transport layers that can provide high carrier selectivity, low defect density, and high processing robustness, simultaneously. In this work, this issue is addressed by studying defect generation and surface passivation of nickel oxide (NiOx). It is revealed that the generation of high oxidation state species on NiOx surface lowers contact resistance but hinders charge extraction when employed as transport layer in organic solar cells. By using them as coordination centers, a straightforward surface modification strategy is implemented using (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) that enhances charge extraction and increases the solar cell efficiency from 11.46% to 17.12%. Additionally, the robustness of this modification across different deposition methods of the carbazole molecule is demonstrated. Finally, by fine-tuning the Fermi level using various carbazole-based molecules, and in particular with ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (4PADCB), a power conversion efficiency of 17.29% is achieved, with an outstanding combination of a VOC of 0.888 V and a fill factor of 80%.
AB - The efficiency of organic solar cells has raised drastically in the past years. However, there is an undeniable lack of hole transport layers that can provide high carrier selectivity, low defect density, and high processing robustness, simultaneously. In this work, this issue is addressed by studying defect generation and surface passivation of nickel oxide (NiOx). It is revealed that the generation of high oxidation state species on NiOx surface lowers contact resistance but hinders charge extraction when employed as transport layer in organic solar cells. By using them as coordination centers, a straightforward surface modification strategy is implemented using (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) that enhances charge extraction and increases the solar cell efficiency from 11.46% to 17.12%. Additionally, the robustness of this modification across different deposition methods of the carbazole molecule is demonstrated. Finally, by fine-tuning the Fermi level using various carbazole-based molecules, and in particular with ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (4PADCB), a power conversion efficiency of 17.29% is achieved, with an outstanding combination of a VOC of 0.888 V and a fill factor of 80%.
KW - charge extraction
KW - defect passivation
KW - hole transport layer
KW - nickel oxide
KW - organic solar cells
UR - http://www.scopus.com/inward/record.url?scp=85214125465&partnerID=8YFLogxK
U2 - 10.1002/aenm.202404981
DO - 10.1002/aenm.202404981
M3 - Article
AN - SCOPUS:85214125465
SN - 1614-6832
JO - Advanced Energy Materials
JF - Advanced Energy Materials
ER -