Application-Targeted Metal Grid-Enhanced Transparent Electrodes for Organic Photovoltaics

N. Burridge, G. Burwell, O. J. Sandberg, A. Armin, P. Meredith, Adv. Electron. Mater. 2024, 2400645. https://doi.org/10.1002/aelm.202400645

This work explores a promising solution to the scalability limitations of organic photovoltaics (OPVs): transparent conducting electrodes (TCEs) enhanced with a metallic grid (g-TCEs).

● The high sheet resistance (Rsheet) of conventional TCE materials like indium tin oxide (ITO) hinders the performance of large-area OPV devices.

● This study examines the potential of g-TCEs to overcome this issue, focusing on their performance under different irradiance levels and TCE Rsheet values.

A key contribution of this research is the introduction of a new figure of merit (FOMTCE) that goes beyond traditional TCE metrics and allows researchers to benchmark TCEs specifically for PV applications.

To demonstrate the practical application of g-TCEs, the researchers fabricated devices using aluminum-doped zinc oxide (AZO) as the TCE material.

● Remarkably, the resulting g-TCEs achieved an Rsheet equivalent to 0.5 Ω □−1 while maintaining an average visible transmittance exceeding 77%.

● This performance surpasses all state-of-the-art monolithic TCE materials, highlighting the potential of g-TCEs to enable the development of large-area, solution-processed PV devices.

How Laoss Simulation Software Was Used

The researchers used LAOSS (version 4.1.3) software by Fluxim AG to simulate large-area (25 and 100 cm2) OPV devices with both monolithic (m-TCE) and gridded (g-TCE) configurations.

● The software allowed them to model the impact of varying TCE Rsheet and grid parameters (like width and inner radius) on device performance metrics such as fill factor, maximum power point voltage, and power conversion efficiency.

● The simulations provided insights into the scalability of OPV devices under different conditions, demonstrating the superior performance of g-TCEs, particularly at larger areas.

● The simulations also helped to validate analytical expressions developed for the FOMTCE and device scalability.

By combining experimental fabrication and characterisation with sophisticated device modelling using LAOSS, the researchers provide a comprehensive assessment of g-TCEs as a viable pathway for scaling up OPV technology.