Aqueous-solution-processable metal oxides for high-performance organic and perovskite solar cells

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Poly(3,4-ethylene dioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is a common hole-transporting material (HTM) in organic solar cells (OSCs) and perovskite solar cells (PSCs).
• The hygroscopic nature of PEDOT:PSS limits its application in high-performance photovoltaic devices.
• Development of stable and effective alternative HTMs is crucial for advancing photovoltaic technology.

Purpose of the Study:

• To explore solution-processed metal oxide thin films (MoO3, GeO2, V2O5, CrO3) as alternative HTMs.
• To evaluate the performance of these novel HTMs in OSCs and PSCs.
• To investigate the potential of these materials for green and low-cost photovoltaic applications.

Main Methods:

• Facile deposition of MoO3, GeO2, V2O5, and CrO3 thin films via direct dissolution of commercial powders in deionized water.
• Characterization of film properties, including work function and hydrophobicity (contact angle).
• Fabrication and performance testing of OSCs and PSCs utilizing the solution-processed HTMs.

Main Results:

• Solution-processed V2O5 (sV2O5) exhibited the highest work function (5.2 eV) and best hydrophobicity (77.2° contact angle).
• sV2O5-based OSCs and PSCs achieved power conversion efficiencies (PCEs) of 8.36% and 14.13%, respectively.
• A composite HTM of PEDOT:PSS and V2O5 achieved a maximum PCE of 18.03% with a V_oc > 1.0 V.

Conclusions:

• Aqueous-solution-processed metal oxide thin films, particularly V2O5, are promising alternatives to PEDOT:PSS as HTMs.
• These materials offer improved hydrophobicity and high performance in photovoltaic devices.
• The simple, eco-friendly preparation method supports the development of green and cost-effective solar cells.